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Good job!!!!

Nice find. Thanks for the info.



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Not sure if anyone is following this post anymore, but I returned to the store the next morning, 7-24 to find the store at 75 and very comfortable.

Checked the high pressure switches I installed, non tripped. Cycled on and off a few times just to test everything and as I was about to throw in the towel the condensor fans start winding down, then off, followed by comps tripping on HPS.

I found the relay for the CFMS with a intermittently open contact. 24v at coil leg 1 closed leg 2 open.... replaced and tested again and all is well. odd how the previous time the contacts " reset" themselves and both CFMS were running at full speed.

Right place at the right time sure is helpful

Thanks to everyone for the info on the CLOs and the other input

Previous post is right probably bad cfm works in morning late afternoon gets hot trip out. Check case temp to see how hot its getting.

Cond Fan Motor

I'd recommend checking for condenser fan motor bearing play. If the shaft moves side to side even a tiny amount, it will overheat and shut off after running a few hours on a hot day.

Regarding tattle tales: Instead, you can wire a very small fuse, such as 1/100 amp or slightly larger in parallel with each safety that will lock out the circuit. When you return and the CLO locked it off, see which fuse blew. If they're all good, then most likely the compressor was not drawing amperage on a call for cooling.

If safeties are on common side of contactor swap wiring to put them on hot side and then maybe a tattle tale will trip.

I am going the route of an overheating condenser fan.

Originally Posted by anthonyac1

i seen one doing the same thing. the one i was working on had one freeze stat wired in series with both contactors. so once it opens it will lock out both.
make sure the evap coil is clean not just the face of the coil but inside. 68 low with 88 inside the space maybe at night your lo side is dropping lower and cutting out both circuits on freeze stat. just an issue i ran into. i put tattle tales also but the clo would pick up the fault not allowing the tattle tale to trip.

I agree the freeze stat is on the common side of the compressor contactors.

i seen one doing the same thing. the one i was working on had one freeze stat wired in series with both contactors. so once it opens it will lock out both.
make sure the evap coil is clean not just the face of the coil but inside. 68 low with 88 inside the space maybe at night your lo side is dropping lower and cutting out both circuits on freeze stat. just an issue i ran into. i put tattle tales also but the clo would pick up the fault not allowing the tattle tale to trip.

Originally Posted by mpr73

stat at 72, clean filters installed today, belt in good condition and tensioned right

What does the economiser board look like?

Originally Posted by Six

It also has a CT on that lockout board thats looking for a current signal.

If you get a signal at Y1,2 and that board doesnt see a current indication it will lock out the circuit.

A chattering relay will lock those things out.

An intermittant fan signal will lock them out causing the freeze stat to trip.

Could be a bad lockout board too

Two bad CLO`s?

It also has a CT on that lockout board thats looking for a current signal.

If you get a signal at Y1,2 and that board doesnt see a current indication it will lock out the circuit.

A chattering relay will lock those things out.

An intermittant fan signal will lock them out causing the freeze stat to trip.

Could be a bad lockout board too

Originally Posted by Dallas Duster

What the stat set for? Filters clean , belt good? Airflow?

stat at 72, clean filters installed today, belt in good condition and tensioned right

Maybe put a tattle tale on the safeties that aren't manual reset. Low press and freeze stat.

What the stat set for? Filters clean , belt good? Airflow?

Originally Posted by mpr73

Carrier
m: 48hjd012-h-571hy
I have gone through the site and found countless threads about these relays. And I think i get them and what causes them to trip.

The issue i didnt see addressed is I am having both clos lock out. I reset unit and cycled. both stages were running 68/325psi. split coils and washed out. 68/245 after coils dried out. Got called back to site later in day, find both locked out again. pressures 72/285, ambient 95 store at 88. I have installed manual switches on discharge line to test overnight. If one locks out it shouldnt lock out the second stage( unless a cond. fan motor is dropping out while Im away) cond fan motors running at 1.3 each rated at 1.3
comps running at 17.6 and 15.2 both rated at 17.6.... form the ambient I wasnt concerned it was running at RLA.....

Anything I may be missing. Will be returning to the site in the morning for a revisit and to dig a lil deeper.

Thanx guys

The only things that can cause the close to drop is high pressure, low pressure, freeze state on evaporator or internal compressor protection. Usually these have both fans running off stage 1 contractors so If it goes. Stage 2is right behind it. I would thoroughly check stage 1 wiring to and from clo. A loose 24v connection or bad #1clo can do this too. Good luck

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carrier clo

Carrier
m: 48hjd012-h-571hy
I have gone through the site and found countless threads about these relays. And I think i get them and what causes them to trip.

The issue i didnt see addressed is I am having both clos lock out. I reset unit and cycled. both stages were running 68/325psi. split coils and washed out. 68/245 after coils dried out. Got called back to site later in day, find both locked out again. pressures 72/285, ambient 95 store at 88. I have installed manual switches on discharge line to test overnight. If one locks out it shouldnt lock out the second stage( unless a cond. fan motor is dropping out while Im away) cond fan motors running at 1.3 each rated at 1.3
comps running at 17.6 and 15.2 both rated at 17.6.... form the ambient I wasnt concerned it was running at RLA.....

Anything I may be missing. Will be returning to the site in the morning for a revisit and to dig a lil deeper.

Thanx guys