unit needs resetting over and over??

[garytulsa]

Can anyone help with this one? I have this 12 ton carrier package unit that has a call for cooling but compressors arent running or outdoor fans. I got voltage but contactors are not engaging. I was told to just hit the disconnect and give it five minutes and turn it back on and it will run. I took a look at it and and found the contactors wont pull in, with a little nudge they suck right in. any ideals what i can look for. model number 48 HJF 012 571HQ thank you for any help.

[ACFIXR]

Check your voltage drop to contactor. Check conductor size.

[invisiblecollar]

Sounds like a bad contactor coil to me.

[garytulsa]

i have high voltage and good low voltage to contactor and its not just one contactor its both compressors and outdoor fan contactor

[KY-kid]

i have high voltage and good low voltage to contactor and its not just one contactor its both compressors and outdoor fan contactor

I am not the greatest trouble shooter for sure - but if you have good control voltage, and the coil is not engaging enough to close them, I would think either something wrong with contactor coil -- or more probable as you said someone suggested in your previous post Loose connection somewhere-- possibly the board has a setting of higher than 5 minutes before it can be turned back on ???

[garytulsa]

I have 3 contactors and all of them are not fully engaging. I did ohm out the contactor coils and they tested good. I am getting good voltage at the relay. I didnt ohm out its coil. Today it ran fine. Seems like every other day and up to three times a day i have to pull the disconnect or just push in the coils. i will check out the line voltage at the disconnect and see if i am gettin a full 440. I am not sure where to go from there. thank you for your help so far.

[sdtech]

Most Carrier unit there is Compressor lock out circuit board for each compressor sometimes unit wont come on when its call for cooling your circuit is open check that first. good luck

[DavyB]

Wait, What? Is this a question, or are you teaching us something??

EDIT: Sorry, my browser popped up with thread #7 first sorry 'bout that.

[DavyB]

Sounds like a bad contactor coil to me.

Sounds like low line voltage to me. time for a new transformer?

[garytulsa]

Not tryin to teach anything dave. I will recheck the components mentioned. Thank you for everyones help. It almost seems like weak magnets but on all three contactors? And the issue is not constant. I am just out of school and starting to see how much I dont know lol. again thanks for everyones time. glad i found the site.

[alpha480v]

Sounds like a low voltage problem. One contactor, maybe contactor problem. All three, possible voltage problem. Could be Clo problem also, they act up alot on Carriers.

[hands]

i have high voltage and good low voltage to contactor and its not just one contactor its both compressors and outdoor fan contactor

Just so I have this right. With a call for cooling you have good low voltage at the contactors but they are not pulled in. If this is the case, I would replace one of the contactors and see if it works.
Are you sure you didn't check the voltage at the contactor while it was pulled in?

[VTP99]

First this is a 10 ton unit.
Second fallow the advice of Davy post #9.

[yellowirenut]

i am thinking its your transformer. u may have 24 Volts but the VA may have dropped..Enough voltage to do the job just just not enough ass behind it.

[flange]

define good low voltage, at around 22 you will have trouble pulling in contactors.possibly transformer tapped wrong?

[timebuilder]

Can anyone help with this one? I have this 12 ton carrier package unit that has a call for cooling but compressors arent running or outdoor fans. I got voltage but contactors are not engaging. I was told to just hit the disconnect and give it five minutes and turn it back on and it will run. I took a look at it and and found the contactors wont pull in, with a little nudge they suck right in. any ideals what i can look for. model number 48 HJF 012 571HQ thank you for any help.

This could be more than one issue. The behavior of pushing in the contactors and they hold is the classic reset of the CLO, compressor lockout board. Your unit has two of these little boards, with a power wire passing through a metal sensing loop.

When you look at the unit, and you have a call for cooling at Y1, make sure you have the same voltage coming back from the economizer, if you have one.

Then BEFORE pushing in the contactor, look for the control voltage at the coil terminals. If it is not there, and then, if you push in the contactor and it holds, you have a lockout issue.

If that is the case, start checking everything else. Pressures, superheat, subcooling, condenser and evap delta T, fan operation, etc.

I have seen low suction pressure as the number one cause of compressor lockout on these Carrier units.

If you have voltage at the compressor contactor and it does not pull in, measure the current. Does the current change if you:

a) jump R to Y1 at the terminal strip?

b) eliminate the Y1 circuit from the economizer? (use the economizer plug or jump the terminals on the economizer logic module)

[timebuilder]

i am thinking its your transformer. u may have 24 Volts but the VA may have dropped..Enough voltage to do the job just just not enough ass behind it.

By that, the meaning is that you can have 24 volts all day, but a high resistance in the circuit can limit current flow, and that will keep a contactor from pulling in, even when the CLO is not an issue.

[pdrake65]

I have 3 contactors and all of them are not fully engaging. I did ohm out the contactor coils and they tested good. I am getting good voltage at the relay. I didnt ohm out its coil. Today it ran fine. Seems like every other day and up to three times a day i have to pull the disconnect or just push in the coils. i will check out the line voltage at the disconnect and see if i am gettin a full 440. I am not sure where to go from there. thank you for your help so far.

Did you check the contactor voltage at the coil before or after pushing them in? Have you checked the voltage with the wires off of the coil? My first guess would be the CLO because when you reset the unit ,it works. check all while it is running and hopefully you will find why it is locking out.

[DavyB]

i am thinking its your transformer. u may have 24 Volts but the VA may have dropped..Enough voltage to do the job just just not enough ass behind it.

Right, you need va. behind your voltage and if the transformer doesn't have the balls anymore, you know what you gotta do.

[Paul Bee]

Does this unit use semi-hermetic compressors? Also I had a carrier about the size you describe doing the same thing after I rinsed the condenser on a cold day. Somehow when the low pressure switch opens it keeps the contactor from pulling in on it's own. But if you push in the contactor it stays in. Another tech told me that is how carrier locks out some of their gaspacks (CLO board). Check your pressure switches or put tattle tales across them and come back later. I agree with timebuilder and pdrake65.

[pdrake65]

i am thinking its your transformer. u may have 24 Volts but the VA may have dropped..Enough voltage to do the job just just not enough ass behind it.

Transformer would be my second guess.

[Randy S.]

Check the line voltage. If it's within spec, then find the voltage drop on the low voltage.
Even in this age of high tech DMMs, a 28V test lamp can be a good friend on the low voltage side, especially dealing with triac or other semiconductor outputs on stuff. Sometimes the high impedance DMMs can lie to you, simply because they are so high impedance.

[garytulsa]

i have 27v from step down transformer also at relay coil and contactor coil. Thank you all for pointing me in a good direction come monday i'll get back on the roof and see what happens. Again thank you everybody for your help!

[ascj]

i have 27v from step down transformer also at relay coil and contactor coil. Thank you all for pointing me in a good direction come monday i'll get back on the roof and see what happens. Again thank you everybody for your help!

You CLO's are locking out, as others have said. I normally check airflow first, since I see more freezestat's locking them out the most.

Also when checking voltage at contactor, check across the two contactor terminals. Not one and ground.

[timebuilder]

i have 27v from step down transformer also at relay coil and contactor coil. Thank you all for pointing me in a good direction come monday i'll get back on the roof and see what happens. Again thank you everybody for your help!

Just make sure you come back and post what you found to this thread until this is resolved, so that there is a beginning, a middle, and yes, an end to the thread.

And you are welcome. We are all here to learn and share.

[VTP99]

i have 27v from step down transformer also at relay coil and contactor coil. Thank you all for pointing me in a good direction come monday i'll get back on the roof and see what happens. Again thank you everybody for your help!

Gary,
Come monday disable two contactors and leave one to quick test transformer.
Or turn unit off and turn I.D. blower on. Provided all are on same transformer.

[timebuilder]

Check the line voltage. If it's within spec, then find the voltage drop on the low voltage.
Even in this age of high tech DMMs, a 28V test lamp can be a good friend on the low voltage side, especially dealing with triac or other semiconductor outputs on stuff. Sometimes the high impedance DMMs can lie to you, simply because they are so high impedance.

So true. High impedance is the way to go on low current electronic circuits, but not always so good in our applications.

[trouble time]

One of the contactor coils is bad. When the contactor tries to pull in it drops the voltage (or va ) in the control circuit. This drop "Hangs up" the other contactors and prevents them from pulling in. Search for the defective contactor, you will find it.

[timebuilder]

One of the contactor coils is bad. When the contactor tries to pull in it drops the voltage (or va ) in the control circuit. This drop "Hangs up" the other contactors and prevents them from pulling in. Search for the defective contactor, you will find it.

I think he has that covered:


I did ohm out the contactor coils and they tested good.


So my money is on the CLO activity.

[ascj]

I have a few techs condemn contactors on Carrier's, because they pushed them in and they held. But they always locked out again.

The CLO's use a triac circuits. By pushing in the contactor, there will be enough current to hold them in.

[sdtech]

I'm a new member trying to help others, Anyway you have your control voltage mostly it is 24VAC. This how the CLO does the s'tats calls for cooling the contactor energized on terminal 3 also energize the CLO logic circuit, must see at least 1.5 amps or the module will lock out. If the sensing loop does not sense amperage its open the contact between 2 and 3 and close contact 2 and X locking out the unit until 24VAC reset. Most Carrier unit has this CLO to monitor one leg of the compressor circuit. good luck

[bamatech]

I see where flange asked in an earlier post if transformer was tapped right.
Have not seen a response ,may have missed it.If so my apologies.
I have seen units do this due to transformer primary not tapped to proper voltage.Usually 208 v unit and trans is tapped to 230v.Doesnt sound like much but it makes a difference when pulling all your low voltage loads at same time.Works sometimes but not always.Has enough voltage to hold your
contactors in but sometimes not pull in last stage. Good luck.

[jtrouse]

Timebuilder at post #16 got the the best possibility IMO. Several others have chimed in on the CLO controls. Pushing in the contactors and then having them stay engaged makes it seem like the control voltage is weak at the contactor or the contactor is bad. What happens is that the CLO is reset when the contactor is manually pushed in and full control voltage is then applied to the contactor.

I thought the CLO should lock out if:
Too low or no amps on the monitored leg after a predetermined length of time allowed for start-up.
After start-up time, too low amps or too high amps on the monitored leg.

If the monitored leg wire is switched to the wrong compressor wire, the CLO can seem like a real PITA.
If a replacement compressor has a different amps from the factory original, the CLO often gets blamed.

[GT Jets]

Pull the common on the CLO and see if she fires off...The CLO needs the common to lock anything out....Common pulled it uses the safeties as a control circuit...So it could potentially short cycle itself to death...

A Redneck temporary fix is to install a delay on break TDR on the Y1 and Y2 circuits and pull the common until you figure out WTFO...

GT

[ascj]

Timebuilder at post #16 got the the best possibility IMO. Several others have chimed in on the CLO controls. Pushing in the contactors and then having them stay engaged makes it seem like the control voltage is weak at the contactor or the contactor is bad. What happens is that the CLO is reset when the contactor is manually pushed in and full control voltage is then applied to the contactor.

I thought the CLO should lock out if:
Too low or no amps on the monitored leg after a predetermined length of time allowed for start-up.
After start-up time, too low amps or too high amps on the monitored leg.

If the monitored leg wire is switched to the wrong compressor wire, the CLO can seem like a real PITA.
If a replacement compressor has a different amps from the factory original, the CLO often gets blamed.

But if you push in the contactor with the CLO locked out, the contactor will engage and remain engaged.

[trouble time]

I think he has that covered:




So my money is on the CLO activity.

That may be, I have seen this before, same problem, it ended up being a contactor.

[ticotech cayman]

have the tranformer been replaced? maybe the VA ARE TOO SMALL , LOOSE OR RUSTY CONECTION SOMEWHERE

[jtrouse]

But if you push in the contactor with the CLO locked out, the contactor will engage and remain engaged.

The CLO will restore full control voltage to the contactor when the contactor is manually pushed in. The CLO resets when it detects the correct amperage on the monitored wire.

[stevehvac]

Ive seen this happen before when the wrong size contactors are used. Check the amp rating of the contactors. If they are suppose to be 30 amp and someone installed three 50 amp contactors you will loose controll voltage at each contactor.

[VTP99]

I'm a new member trying to help others, Anyway you have your control voltage mostly it is 24VAC. This how the CLO does the s'tats calls for cooling the contactor energized on terminal 3 also energize the CLO logic circuit, must see at least 1.5 amps or the module will lock out. If the sensing loop does not sense amperage its open the contact between 2 and 3 and close contact 2 and X locking out the unit until 24VAC reset. Most Carrier unit has this CLO to monitor one leg of the compressor circuit. good luck

SD,
This is correct. Y1 Blue wire goes thru ecno plug and comes out Gray goes to #2 terminal on 1st CLO. Goes thru CLO to n/c contacts at terminal #3. Then leaves CLO on to HPS than LPS then #1 compressor contactor. Terminal #1 Brown is com. for CLO's & White is x terminal normally open and goes back to connection board. Y2 Yellow wire goes thru ecno plug and comes out Orange goes to #2 terminal on 2nd CLO. And repeats as above.
Question is how can it measure any compressor leg amps if the contactor has never engaged ?
Also if OP has 24 volts @ contactor it already made it thru all the hoops described above.
Now if the contactor engaged then disengaged because of no amp read i would look at the CLO.
Ever have a car with the lights working but when you try to start they dim ? You could read 12 volts @ the battery but have no cranking AMPS.
Just my :.02:

[sdtech]

The CLO is preventing the unit not to run there is other problem in the control circuit like you described like economizer there is a problem not allowing the cooling to run stuck 100% open may be still economizer mode using OA for cooling, and there is temp.disc behind econo actuator may be bad. You can bypass the CLO or putting a jumper wire just see if it work, 100% it works unless you don't have other problem, Carrier put those for safety. to answer your question of course you can not measure comp. amp not energized.

[VTP99]

The CLO is preventing the unit not to run there is other problem in the control circuit like you described like economizer there is a problem not allowing the cooling to run stuck 100% open may be still economizer mode using OA for cooling, and there is temp.disc behind econo actuator may be bad. You can bypass the CLO or putting a jumper wire just see if it work, 100% it works unless you don't have other problem, Carrier put those for safety. to answer your question of course you can not measure comp. amp not energized.

SD,
OP said he had 24v at the contactor coil. So i would think that the CLO is functioning correctly or it would not send 24v thru it on to contactor. Yes or no ?
P.S.
To dis enable the CLO just pull the Brown wire @ terminal # 1 as GT said.

[sdtech]

Dear VTP99,
If you do have 24VAC on your contactor coil and line voltage 3ph or 1ph if the coil is good its should pull in and compressor will run i don't see no problem and the answer to your question yes and pulling out brown you can disable it, I apologized did not know you have other question sorry my friend.

[timebuilder]

SD,
OP said he had 24v at the contactor coil. So i would think that the CLO is functioning correctly or it would not send 24v thru it on to contactor. Yes or no ?
P.S.
To dis enable the CLO just pull the Brown wire @ terminal # 1 as GT said.

I know he did say that voltage was good at the coil, but there may be low current due to the CLO.

Not a lot is published about this CLO device, but what I have seen tells me that the unit DOES run when reset by pushing in the contactor, and when that happens, the current sensing loop reacts to the current through that wire that passes through the loop, and the lockout circuit is reset. Then, the unit runs until a fault is detected (let's say a low pressure switch opens) and the contactor opens and, voilà, a lockout.

When I see this behavior, I start looking for safeties that open and lockout the compressor. I've never taken the time to see if a voltage is still measurable at the contactor coil. There may indeed be 24 volts at the coil, and yet, the CLO may limit its current so the coil cannot pull in the contactor.

The bottom line, IMHO, is that this behavior is consistent with a compressor lockout, but more testing is needed. When you are presented with a puzzle like this the first couple of times, you may not be able to think it through clearly. As you come to understand what is actually happening, your approach becomes more clear, and your ability to accurately gather the info and interpret it gets better and better.

[VTP99]

Dear VTP99,
If you do have 24VAC on your contactor coil and line voltage 3ph or 1ph if the coil is good its should pull in and compressor will run i don't see no problem and the answer to your question yes and pulling out brown you can disable it, I apologized did not know you have other question sorry my friend.

No need to apologize. Thank you for your response. Glad you found this site. All of us are here to learn i hope. Also thank you for clarifying. Are you in the trade ? Probably a stupid question. I'm sure you know about Pro Membership.

[VTP99]

I know he did say that voltage was good at the coil, but there may be low current due to the CLO.

Not a lot is published about this CLO device, but what I have seen tells me that the unit DOES run when reset by pushing in the contactor, and when that happens, the current sensing loop reacts to the current through that wire that passes through the loop, and the lockout circuit is reset. Then, the unit runs until a fault is detected (let's say a low pressure switch opens) and the contactor opens and, voilà, a lockout.

When I see this behavior, I start looking for safeties that open and lockout the compressor. I've never taken the time to see if a voltage is still measurable at the contactor coil. There may indeed be 24 volts at the coil, and yet, the CLO may limit its current so the coil cannot pull in the contactor.

The bottom line, IMHO, is that this behavior is consistent with a compressor lockout, but more testing is needed. When you are presented with a puzzle like this the first couple of times, you may not be able to think it through clearly. As you come to understand what is actually happening, your approach becomes more clear, and your ability to accurately gather the info and interpret it gets better and better.

Time, My question is how could the CLO limit. It either allows low voltage to pass thru terminal 2 to 3 or it opens 3 and closes x and goes back to connection board. Now if a lock out is initiated because of a fault there would no longer be 24v @ the contactor. Were as OP says there is voltage there.

[timebuilder]

Time, My question is how could the CLO limit. It either allows low voltage to pass thru terminal 2 to 3 or it opens 3 and closes x and goes back to connection board. Now if a lock out is initiated because of a fault there would no longer be 24v @ the contactor. Were as OP says there is voltage there.

Well, it could be that 1) the voltage was not actually measured at the contactor, or 2) it was measured after being reset, or 3) there is still a voltage present at the coil, but the lockout board limits current so it cannot pull in.

I was able to do a search and find a description of the board operation, and I discovered that a minimum of 1.5 amps must be sensed by the current loop. So, if a refrigerant charge was lost, and current dropped below that point, it would lock out the board. The site was not a Carrier site, and there could be more to it. I'm going to have to grab one of these from a scrapped unit now, and bench test it.

Oh, and the board resets if the 24v feed is lost, and of course, that happens if the power to the unit is turned off or the call for cooling is withdrawn.

That said, I can tell you that it is not difficult to design a lockout that merely reduces current, and allows the voltage to be measurable with a high impedance meter, like most of us use nowadays.

I'm sure the op is going to look at this again, and hopefully, he will come back and post his findings.

[VTP99]

Well, it could be that 1) the voltage was not actually measured at the contactor, or 2) it was measured after being reset, or 3) there is still a voltage present at the coil, but the lockout board limits current so it cannot pull in.

I was able to do a search and find a description of the board operation, and I discovered that a minimum of 1.5 amps must be sensed by the current loop. So, if a refrigerant charge was lost, and current dropped below that point, it would lock out the board. The site was not a Carrier site, and there could be more to it. I'm going to have to grab one of these from a scrapped unit now, and bench test it.

Oh, and the board resets if the 24v feed is lost, and of course, that happens if the power to the unit is turned off or the call for cooling is withdrawn.

That said, I can tell you that it is not difficult to design a lockout that merely reduces current, and allows the voltage to be measurable with a high impedance meter, like most of us use nowadays.

I'm sure the op is going to look at this again, and hopefully, he will come back and post his findings.

Time,
OP said he had good voltage at contactor in post #4. I see the CLO as a protection device to monitor compressor power supply. On 3 phase to protect against single phasing. The unit already has protection for high & low pressure. Just to clarify my writing here, I'm am just thinking this from looking at the wiring diagram. You could very well be right that that board limits low voltage current. I just don't see that from the wiring drawing. So i guess the real question is does this device limit or just turn on turn off. Test that board and lets find out.:)

[timebuilder]

Time,
OP said he had good voltage at contactor in post #4. I see the CLO as a protection device to monitor compressor power supply. On 3 phase to protect against single phasing. The unit already has protection for high & low pressure. Just to clarify my writing here, I'm am just thinking this from looking at the wiring diagram. You could very well be right that that board limits low voltage current. I just don't see that from the wiring drawing. So i guess the real question is does this device limit or just turn on turn off. Test that board and lets find out.:)

Ok. The only problems I have had with compressor lockout were due to low charge.

I see what he said in post #4. I'm suggesting that may not be correct.

Talk to you guys later. :angel:

[Dallas Duster]

But if you push in the contactor with the CLO locked out, the contactor will engage and remain engaged.

You know I have never seen this happen on this kind of unit. Can you explain more on how this can happen? TIA

[sdtech]

Dear VTP99,
You asked me if i'am on the trade yes, from San Diego area this is good site thank you for asking friend

[timebuilder]

Welcome. I'd say that most of us enjoy the sharing of ideas. I try to learn something new every day.

[ascj]

You know I have never seen this happen on this kind of unit. Can you explain more on how this can happen? TIA

It you push the contactor in......you now have current running through the compressor wire on the clo. So clo, now will send 24v to the contactor and keep it energized until it trips out on safety again.

[Dallas Duster]

It you push the contactor in......you now have current running through the compressor wire on the clo. So clo, now will send 24v to the contactor and keep it energized until it trips out on safety again.

And this resets the lockout relay ? I just have never seen this before except on some older RTU's the a circuit board with the clo protection built into it. Just saying. I will try this when I get a chance.

[ascj]

And this resets the lockout relay ? I just have never seen this before except on some older RTU's the a circuit board with the clo protection built into it. Just saying. I will try this when I get a chance.

Another tech went to a no A/C on a 5 ton Carrier. Found bad condenser fan motor, replaced it. Two days later, no A/C. Another tech went out and diagnosed bad contactor. He measured 24v from the contactor to ground and when he pushed it in, it stay pulled in and ran.
Next day, no A/C. I went there with the second tech. We find the unit locked out. I reset it. Checked charge, air flow, and amperages. I find the condenser fan drawing a little high amps. Kept checking the temp of the motor. It kept climbing. 25 minutes later the motor quits on thermal. Come to find out the original 1/3hp 825rpm motor was replaced with a 1/3hp 1075rpm. Installed right motor....all good.

http://hvac-talk.com/vbb/showthread.php?t=307882&highlight=motor

[timebuilder]

And this resets the lockout relay ? I just have never seen this before except on some older RTU's the a circuit board with the clo protection built into it. Just saying. I will try this when I get a chance.


I remember the first time I saw one of these CLO thingies. I pushed the contactor in and the thing ran. I'm thinking, what the...

So I called the service manager, and he told me I had just reset the lockout. I'm like, I did whaaat? :D

[jtrouse]

Another tech went to a no A/C on a 5 ton Carrier. Found bad condenser fan motor, replaced it. Two days later, no A/C. Another tech went out and diagnosed bad contactor. He measured 24v from the contactor to ground and when he pushed it in, it stay pulled in and ran.
Next day, no A/C. I went there with the second tech. We find the unit locked out. I reset it. Checked charge, air flow, and amperages. I find the condenser fan drawing a little high amps. Kept checking the temp of the motor. It kept climbing. 25 minutes later the motor quits on thermal. Come to find out the original 1/3hp 825rpm motor was replaced with a 1/3hp 1075rpm. Installed right motor....all good.

http://hvac-talk.com/vbb/showthread.php?t=307882&highlight=motor


ascj, looks like the CLO did a good job, just what it is there for.

[timebuilder]

Can anyone help with this one? I have this 12 ton carrier package unit that has a call for cooling but compressors arent running or outdoor fans. I got voltage but contactors are not engaging. I was told to just hit the disconnect and give it five minutes and turn it back on and it will run. I took a look at it and and found the contactors wont pull in, with a little nudge they suck right in. any ideals what i can look for. model number 48 HJF 012 571HQ thank you for any help.


Gaaaaary.....

time for an update.........

[VTP99]

Gaaaaary.....

time for an update.........

He's still pushing the contactors in. :eek:

[timebuilder]

I know, I'm just looking for a miracle....:angel:

[VTP99]

I know, I'm just looking for a miracle....:angel:

Or a Paul Harvey :yes:

[sdtech]

Time,
Last time VTP99 posted and explained it real good and how the circuit connected to economizer to CLO. This morning i'm looking at the wiring diagram and we want to make sure there is no open circuit each one of those components parts. If we go back how the circuit connected and follow each components in a circuit you can find some may be open that's why C1 coil not pulling in. Here is the circuit connection that VTP99 laid out last posted, Y1 Blue to economizer plug in #2 connected #5 Gray to CLO1 terminal #2 to NC contact terminal #3 to HPS to LPS to C1 contactor coil make sure no open circuit there. And the common wire of C1 coil is Brown connected to FPT (Freeze up Protection Thermostat) which is Black wire connected to Brown common side of the 24VAC transformer. Let say the 24VAC RED make and passed to Y1 and you follow each connection should catch the open circuit as you go. And the FPT is common side make sure not open. I think we are good there, Thanks

[sdtech]

VTP99,
Any luck on that Carrier unit yet!

[VTP99]

VTP99,
Any luck on that Carrier unit yet!

Sd,
Time put a shout out for Gary in Tulsa but so far no post yet. Sometimes you get that here. No end to the story :mad: It was Gary in post #1 that was pushing the contactors in.
Time,
Did you dig up a old board to bench test ?

[Jettaknight]

Sounds like low line voltage to me. time for a new transformer?
I remember once where the unit was rated for 208v or 240v. The transformer had spade connectors that could be set for either voltage. Same problem as the OP described was happening. Turned out it was the transformer. 208v was supplied but the transformer was wired for 240v. Not enough voltage to pull in the contactors.

However this one is a 12 ton so its probably 208 or 575 3ph. I'd still be looking at the transformer...

[sdtech]

VTP99,
Yeah I understand how things out there alright men hope Gary come back and tell us. Thanks...

[sdtech]

JettaKnight,
Yes it can happen my friend

[VTP99]

I remember once where the unit was rated for 208v or 240v. The transformer had spade connectors that could be set for either voltage. Same problem as the OP described was happening. Turned out it was the transformer. 208v was supplied but the transformer was wired for 240v. Not enough voltage to pull in the contactors.

However this one is a 12 ton so its probably 208 or 575 3ph. I'd still be looking at the transformer...

Jetta,
It's a 10 ton unit 012 equals 10 ton by Carrier's nomenclature. ( It's a carrier thing ) Your right about the trasformer line taps. I see that mistake often. Also i believe he said it was 480 volt 3 phase.

[timebuilder]

Sd,
Time put a shout out for Gary in Tulsa but so far no post yet. Sometimes you get that here. No end to the story :mad: It was Gary in post #1 that was pushing the contactors in.
Time,
Did you dig up a old board to bench test ?

I'm hoping to find one on an upcoming changeout.

[Dallas Duster]

Sd,
Time put a shout out for Gary in Tulsa but so far no post yet. Sometimes you get that here. No end to the story :mad: It was Gary in post #1 that was pushing the contactors in.
Time,
Did you dig up a old board to bench test ?

With all the tornadoes out there in OKlahoma maybe that RTU is not on the roof still and Gary is OK no pun intended.

[VTP99]

With all the tornadoes out there in OKlahoma maybe that RTU is not on the roof still and Gary is OK no pun intended.

thegoodlistener,
I haven't been watching the weather channel lately. Any of those tornadoes touch down by you ? Those things will put the fear of god in ya. :eek2:

[Dallas Duster]

thegoodlistener,
I haven't been watching the weather channel lately. Any of those tornadoes touch down by you ? Those things will put the fear of god in ya. :eek2:

We had a F1 hit my small east Texas town about 3 weeks ago. It didn't hurt anybody but it messed up lots of roofs and older buildings. Plus it really messed up my favorite DQ.

[VTP99]

We had a F1 hit my small east Texas town about 3 weeks ago. It didn't hurt anybody but it messed up lots of roofs and older buildings. Plus it really messed up my favorite DQ.

What no more Tin Roof no pun intended.:)

[timebuilder]

We had a F1 hit my small east Texas town about 3 weeks ago. It didn't hurt anybody but it messed up lots of roofs and older buildings. Plus it really messed up my favorite DQ.

Mmmmm. DQ.

I think I should go out and get a hot fudge sundae after my exam today....

[VTP99]

Mmmmm. DQ.

I think I should go out and get a hot fudge sundae after my exam today....

I read that in the other thread. I have been delaying that test myself because of all the jokes associated with it. Hope all goes well for you and ya might think twice about fudge after that test.

[timebuilder]

I read that in the other thread. I have been delaying that test myself because of all the jokes associated with it. Hope all goes well for you and ya might think twice about fudge after that test.


LOL!!

I'm going to have a real meal first, trust me. I haven't had food since Tuesday night.

This is my third exam in eight years. The jet co insurance paid for the the first two. This one is out of pocket, since my current co has no health insurance. One of our guys had a heart attack, so we can't afford to insure the rest of us.

Even so, I'm glad that I can pay for this and have it available, rather than have it be free, and not be able to get the care.

I usually tell the Doc that if he finds Jimmy Hoffa, I want the book and movie rights. :yes:

[timebuilder]

1) No problems found

2) Nice steak at Outback.

[timebuilder]

VTP99,
Yeah I understand how things out there alright men hope Gary come back and tell us. Thanks...

Okay, back to the thread.

Gary, give us an update.

[garytulsa]

ok thank you everybody who gave me advise! I found the problem it was going off on CLO. I jumpered and the contactors sucked in put my gauges on and wow high pressure. The hvac tech before me must have charged it beer can cold. I recoverd some refrig and put the correct charge on it. Now it runs fine. The unit conditions a kitchen and there is alot of heat load which may have been why the guy charged it like he did who knows. Being new to the facility I was told to only reset it and not givin the chance to take any time with it. Again thank you everybody you made me look good to the boss! Sorry I didnt post sooner. I had a major problem with a very big York chiller. I got it running seems something wasnt right in the programing. I am clueless on that unit but it's running. Good thing I have you guys as back up lol.

[garytulsa]

Oh thought I would clarify a few. When the unit first went off on my watch. I looked for a call for cooling had 24v to Y1 & Y2. Checked for 24v to relay, good. Checked for line voltage to contactor good. Also ohmed out the contactor coils, little to no resistance. I did check voltage to the contactor coil but after I pushed in the contactor. (Stupid of me) After seeing what time had to say and others I went back and when the unit went off again. I tested it as it sat. 24 to y 24 to relay. No voltage at compressor or outdoor fan contactor coil but voltage to indoor contactor coil. Good line voltage going to contactor. 24v goin to both CLO's but no voltage coming out. I tested voltage at the pressure switches but got nothing. I tested voltage to compressor 112 on each leg. I jumped 2 & 3 at the CLO and it fired up. Then I tested amps to compressor. around 15 amps. put the gauges on and 80 lo side 375 pisg. I had just cleaned both coils earlier. Fans on and good air flow.

[jtrouse]

Oh thought I would clarify a few. When the unit first went off on my watch. I looked for a call for cooling had 24v to Y1 & Y2. Checked for 24v to relay, good. Checked for line voltage to contactor good. I did check voltage to the contactor coil but after I pushed in the contactor. (Stupid of me) After seeing what time had to say and others I went back and when the unit went off again. I tested it as it sat. 24 to y 24 to relay. No voltage at compressor or outdoor fan contactor coil but voltage to indoor contactor coil. Good line voltage going to contactor. 24v goin to both CLO's but no voltage coming out. I tested voltage to compressor 112 on each leg. I jumped 2 & 3 at the CLO and it fired up. Then I tested amps to compressor. around 15 amps. put the gauges on and 80 lo side 375 pisg. I had just cleaned both coils earlier. Fans on and good air flow.


Where you said "Stupid of me" I would disagree. Then all of us would be "stupid"; especially me. I've never in over 45 years of service found any contactor safety devices that reset by manually engaging the contactor relay like these CLO's do. It stumped me for a while too.

Smart of you to know something different was going on.
Smart of you to to try to figure it out and not just walk away from it.
Smart of you to seek an answer and ask others when you don't know yet.
Smart of you to follow through the way you seem to have done here.

Looks like you're doing fine now and will do well in the future.

Also, are you what I would call "in-house maintenance" at the facility you mentioned? That is what I've been doing for the last 10 years.

[garytulsa]

Yes I am in house maintenance guy. I went to HVAC school worked for three differnt companys in install tryin to work my way to service. Then took a possition as heat and air guy on facility maintenance crew.

[VTP99]

[QUOTE=garytulsa;6670832 I tested it as it sat. 24 to y 24 to relay. No voltage at compressor or outdoor fan contactor coil but voltage to indoor contactor coil. Good line voltage going to contactor. 24v goin to both CLO's but no voltage coming out. I tested voltage at the pressure switches but got nothing. I tested voltage to compressor 112 on each leg. I jumped 2 & 3 at the CLO and it fired up. Then I tested amps to compressor. around 15 amps. put the gauges on and 80 lo side 375 pisg. I had just cleaned both coils earlier. Fans on and good air flow.[/QUOTE]

Ok Gary,
Looks like a win win situation for all parties involved.
No voltage at comp. or fan contactor. But voltage to blower contactor because not part of the 2-CLO's. Makes sense so far. Voltage into both CLO's terminals #2 but not out to terminal #3. If you would have checked terminal X you would have found it there. When you checked voltage at the pressure switches of course none there because it has to come from terminal #3 which was open due to CLO. When you jumped 2 & 3 you bypassed the CLO and apparently the high pressure switch had reset to a lower pressure and it fired up. Sooooooooo when the system is operating and one of the two pressure switches opens it kills low voltage to the contactor removing power passing thru the magic CLO loop triggering the CLO to trip.
Wow i hope i never forget this.
Great thread Gary and thanks for following up. I hope we all learned something here.

[seabiscuit]

Great you found the problem, it'll happen again so why don't you throw a delay on break relay in, and use the two wires from CLO. If it does happen again, then it will be automatically reset to what length you dial in.

[timebuilder]

Gary-

This is a common problem on these Carrier units.

Carrier does not use a txv on this design. It's a set of orifices in the header manifold going into the evaporator. Typically, a PM visitor notices some frosting on the headers, and sees high superheat, if he looks at that value at all.

In an attempt to lower the superheat to an acceptable level, or just get rid of the frosting, he adds refrigerant.

The fix for these units is to recover the refrigerant and replace the clogged header. Of course, you first eliminate all other restrictions first, but I have found two of these in the past year on these 1990's vintage Carrier RTU's.

Check back at some point and see if the readings, particularly the superheat, are still good.

Nice job!!!

[sdtech]

Gary'
Thank you for all your hard work that's good job found the problem that's great men.

[Dallas Duster]

Hey Timebuilder you might want to reread the first paragraph of your last post.

[springer ray]

How manny VA is your X-Former and how manny feet is your Tstat wire?

[timebuilder]

Hey Timebuilder you might want to reread the first paragraph of your last post.

I take it you are about to say that you have seen some of these with txv's. I have not.

I see the txv's used on the shorter models with the recessed fans. I believe the older ones were the DR series.

Was that what you were referring to? Or was it the use of "low" instead of "high?" ;)

Must be morning after propofol syndrome....

[pdrake65]

Gary-

This is a common problem on these Carrier units.

Carrier does not use a txv on this design. It's a set of orifices in the header manifold going into the evaporator. Typically, a PM visitor notices some frosting on the headers, and sees high superheat, if he looks at that value at all.

In an attempt to lower the superheat to an acceptable level, or just get rid of the frosting, he adds refrigerant.

The fix for these units is to recover the refrigerant and replace the clogged header. Of course, you first eliminate all other restrictions first, but I have found two of these in the past year on these 1990's vintage Carrier RTU's.

Check back at some point and see if the readings, particularly the superheat, are still good.

Nice job!!!

Timebuilder, You have not had any luck in blowing the clog out of the header? I have had quite a bit of success in doing that in the past.

[timebuilder]

Timebuilder, You have not had any luck in blowing the clog out of the header? I have had quite a bit of success in doing that in the past.

We made a decision that this approach was going to give the most consistent positive result. In many cases, telling a customer that something "might" work is equivalent to saying it "will " work, in the mind of the customer. Then, after trying to blow it out, we "own" it until it works properly.

This way, we quote, repair, and it's done.

[pdrake65]

We made a decision that this rAdrienne Janicwas going to give the most consistent positive result. In many cases, telling a customer that something "might" work is equivalent to saying it "will " work, in the mind of the customer. Then, after trying to blow it out, we "own" it until it works properly.

This way, we quote, repair, and it's done.

Good logic! :yes:

[timebuilder]

Good logic! :yes:


Looks like a computer hiccup. I was watching an old "OverHaulin' " last night, with AJ.

It's the episode where Chip is surprised with his rebuilt pickup at the trade show.

I've edited the post you quoted.

[Dallas Duster]

I take it you are about to say that you have seen some of these with txv's. I have not.

I see the txv's used on the shorter models with the recessed fans. I believe the older ones were the DR series.

Was that what you were referring to? Or was it the use of "low" instead of "high?" ;)

Must be morning after propofol syndrome....

Bingo I didn't want anyone else give you hell but me!!!! :pileon:

[pdrake65]

Looks like a computer hiccup. I was watching an old "OverHaulin' " last night, with AJ.

It's the episode where Chip is surprised with his rebuilt pickup at the trade show.

I've edited the post you quoted.

Got that. I am good at reading between the lines. :D

[timebuilder]

Bingo I didn't want anyone else give you hell but me!!!! :pileon:


You know, it's hard to imagine Michael Jackson taking that Propofol stuff on a regular basis. Even though I was clear headed a few hours after the procedure, I was as still a little slow getting up to speed on Friday morning.

Good of you to notice that!

[Dallas Duster]

You know, it's hard to imagine Michael Jackson taking that Propofol stuff on a regular basis. Even though I was clear headed a few hours after the procedure, I was as still a little slow getting up to speed on Friday morning.

Good of you to notice that!

Well if I know you and me we don't want to lead someone down the wrong path and make someone make a mistake.
It's good that you have a better doc than MJ!!!!!!

[timebuilder]

Well if I know you and me we don't want to lead someone down the wrong path and make someone make a mistake.
It's good that you have a better doc than MJ!!!!!!

Well, I was mentally prepared to wake up in Glory, but I'm glad to have the additional time to help others.

Maybe it was just a little dyslexia....:angel: