unit needs resetting over and over??

[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!

[timebuilder]

Good logic!

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!!!!

[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.

[timebuilder]

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

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....