unit needs resetting over and over??

[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