ReplyWhy would you leave with a compressor running 225/200 without resolving the issue ?
Of course its going to trip again.
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So I just installed a complete Rheem 5 ton, 14ajm series system ast november. HO tells me its not cooling as good. I arrive to find a loud compressor, 200 psi suction and 275 head. First thing that comes to mind is bad valves. A few minutes later the compressor cuts off on internal overload. I take a hose and cool it off. 10 min later, compressor kicks back on and pressures now seem normal (130/325) 13 subcool , 19 delta t. So I let it run for 20 minutes and take off. An hour later , HO called back and outdoor unit has stoppes running again. Bad txv?
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Why would you leave with a compressor running 225/200 without resolving the issue ?
Of course its going to trip again.
Professional Member
Overfeed. possible loose bulb or poorly insulated, over sized.
Suction pressure high, head pressure low, superheat low, subcooling low, amp low.
I don't see any superheat or subcooling
I dont warranty Tinkeritus
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I was planning on going back to replace the txv. Just wanted some feedbackOriginally Posted by Six
when life throws me a banjo, i play it
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Is the suction line very cold? If not I would suspect the internal releif valve in the compressor.
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My above question applies when the unit is malfunctioning. I'm assuming the condenser fan was running? Condenser fan shutting off, when your not there? Check fan amps and the cap.
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Ah...ok.
Well someone mentioned a week internal relief that sounds reasonable.
Even if your txv was wide open you wouldnt be equalizing like that.
It almost sounds like its a scroll running backwards.
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bad valves or internal releaf open
a stupid question is a question you wont to ask, but don't
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If bad valves, it wouldn't have returned to normal pressures.
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Exactly
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Ok this makes sense. IRV pops, compressor gets hot, then goes off on internal overload? Ive never had one do that but logical...
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Sounds like a scroll running backwards to me as well. I was working on unit the other day and we had a little power brown out and the neighbors rheem unit started running backwards. I reset the breaker and it started up fine. Maybe they have a bad connection or floatswitch that is causing the unit to short cycle. Install a time delay and check your wiring inside and and out.
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Its single phase. You mean its running backwards on overload?
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During a very brief power interruption (brown out) the expansion of gas in the compressor can start moving the rotor in reverse. If power is applied during that rotation it is possible for the motor to start running backwards until it overheats and it can do damage to the scroll. It can't pump so the motor isn't cooled by the suction vapor anymore. I had heard that Copeland fixed this issue at some point, but I still see it on equipement built in the last 5 years. For the record, I have only seen this happen to Copeland scrolls.
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I'm with Dave.
I'd take the proactive step of installing a time delay.
For me, the "loud compressor" you mentioned right out of the box, along with the pressures, suggests to me it is getting started in the wrong direction. A time delay will help inhibit that effect.
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2 Tim 3:16-17
RSES CMS, HVAC Electrical Specialist
Member, IAEI
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Thougjt the visionpro stat had a time delay but it very well could be disabled. Thanks.
when life throws me a banjo, i play it
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It has it, and it is adjustable in installer setup.
BUT, it works based on when it (the stat) turns the compressor off ITSELF, or when it "wakes up" from a full power down.
If power is lost, the backup batteries don't let the stat know the compressor stopped, so it will come back on as soon as power is restored.
I think the time delay is a better choice than taking out the batteries, as most HO's would not like to have to reprogram the stat for time whenever the power goes off.
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2 Tim 3:16-17
RSES CMS, HVAC Electrical Specialist
Member, IAEI
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I had one do that same exact thing tuesday. 11 year old Ruud 3 ton. Except it was running great, good pressures, subcool, superheat, delta T. It never shut off. Pressures went to about 200/275 compressor got REALLY hot. Was rated for 16.5 amps and was pulling 11.5 on one hot leg 3.5 on another. It had a leak in the evap coil and HO just wanted a whole new system
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What about installing a 5-2-1 on the unit ? Wouldn't it increase starting torque ?
Also a delay on make timer is cheap too if you want a no fail delay.
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older scrolls had a habit of starting up and running backwards due to a momentary loss of power. newer ones are not supposed to do that but it sounds like yours might be.
i would try putting a delay on break timer right before the contactor, only needs to be set for 15 seconds or so to prevent reverse running from happening.
something to try and much easier than a txv.
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