Internal OL tripping

[tonydykes55]

Called back today. Breaker tripped on unit. Amperage has gone up to 85. When I left it was around 63 amps. It ran good for a few days. Voltage is 205 at the disconnect all the way to the compressor, loaded down - no voltage drop. Won't hold but 20 seconds. Reset it a few times to check amps and volts, then left it off for 10 minutes and tried again. Now it kicks within 3 or 4 seconds - pulling over 110 amps. Sounds like valves are sticking.

[Six]

Bottom line is proper charging methods. Focusing on the split as a method to add or remove refrigerant is hack methodology.

Its a mistake. Your low split could be a symptom of several issues.

[timebuilder]

Been up there all day. RLA = 62 on nameplate. All wires and connections clean. No voltage drop across contacts. 210 phase to phase at compressor. Been monitoring amps closely to see what it trips at. Oh, first thing pulled a hose up and cleaned cond coils with cleaner. Started up. Pulling 77 - 80 amps. Cut off after about 5 min. Comp only, not fans. 4 safety switches in series - hi limit, lo limit, internal OL's, and a CLO ( comp lockout) which is on a small ckt bd and that is what was opening, not the Ovlds. So I jumped them (CLO). A ckt breaker on the unit, feeding the compressor (not the disconnect) started tripping at that point. Can't find amp rating on it. Amps got higher as it got hotter - in the low to mid 80s. Won't run long enough at this point to get SH. So I started removing charge. Head pressure was 345. Suction 75 with clean coils. Bumped out all I could. Amps started dropping. Got recovery machine. Kept removing - checking amps. Took out maybe 20 lbs - didn't have scales up there. Factory charge is 19 lbs. got the amps down to 62. Head 235 suction 65. Dont know SH. Haven't checked air temps. All my equip is still on the roof. Had to take another call. It's looking good. I'll be back tomorrow to check air temps. It was running for over an hour when I left.

Nope.

The CLO only locks out the unit when the safety chain opens (and the sensing loop has to see at least 1.5 amps). You WERE tripping something. I'd pull the charge, vac it down, and weigh in. No telling what is in there, including non-condensibles.

[tonydykes55]

True. But I've run across very old units, like this one and have cleaned the coils, properly charged (whether by weighing, sc, or sh) only to find out that they are simply worn out (compressor, bearings, coils, motors - maybe a combination of all - not just one issue), then the only choice is a new unit, therefore the only other option is to get a good split regardless of the charge. Am I wrong. Thanks for the help everyone!

[tonydykes55]

Ok so I'll try sucking her down, pull deep vac and weigh in new charge. It wouldn't be cheap or easy to change compressor. But I'll say this - that compressor sounded grim on that last attempt. All the windings ohmed out good, not grounded either. Maybe there is hope.

[timebuilder]

True. But I've run across very old units, like this one and have cleaned the coils, properly charged (whether by weighing, sc, or sh) only to find out that they are simply worn out (compressor, bearings, coils, motors - maybe a combination of all - not just one issue), then the only choice is a new unit, therefore the only other option is to get a good split regardless of the charge. Am I wrong. Thanks for the help everyone!

Since you are pulling out charge anyway, finish the job and weigh it in. Then, you can eliminate that as a variable.

[tonydykes55]

Will do. Gotta go for now. I'll check back.

[tonydykes55]

Sucked it down today. Pulled deep vac. New charge - weighed in nameplate charge exactly. Same symptoms. Valves sound loud. Pulling excessive amps - 90 - 110. Kicking breaker.

[timebuilder]

How are the SH and SC numbers? This can tell you what the refrigerant is doing.

[tonydykes55]

Trips within a few seconds. Wont run long enough to get sc & sh. Tenfirst time i cut it on with new charge it ran maybe a minute or so - the pressures looked good for the time it was running - suc 75 Head 250. But it was loud. The valves sound like theyre gone - clattering. I plan on ordering a rebuilt comp tomorrow. Comes with full warranty. I even changed the oil today. Got to be bad compressor valves.

[darkbeekeeper]

Wow

[timebuilder]

Trips within a few seconds. Wont run long enough to get sc & sh. Tenfirst time i cut it on with new charge it ran maybe a minute or so - the pressures looked good for the time it was running - suc 75 Head 250. But it was loud. The valves sound like theyre gone - clattering. I plan on ordering a rebuilt comp tomorrow. Comes with full warranty. I even changed the oil today. Got to be bad compressor valves.

Well, keep us informed about the new compressor. I take it you heard the same noise initially, when you would reset the compressor, and it would run for a day, right? Or is the noise new? Did the suction line temp drop when it ran, and did the space cool for the 24 hours or so when it would run?

[tonydykes55]

As stated earlier, my very first call (when it was still cooling) was a noise problem. And it's gone downhill since. I'm headed out today, thanks. Oh and being my pressures look good I have no reason to suspect a bad txv, right?

[Push It]

If it is an 06D did you check the oil level. I have read (never experienced it) that a high oil level can cause increased amp draw on the semihermetic because the crank is sumerging in it. A high oil level could also have caused the compressor to bust something interally. Does anyone else see this as possible? Again I have never run into it yet myself.

[tonydykes55]

Sight glass was very dark. Could see no oil, although it had a good bit?..I drained and replaced with 115 oz to specs

[carmon]

oh boy...... troubles abound

[tonydykes55]

Set the new compressor tues. it rained for two days so I got back up today and started it. Pulled vac & weighed charge. Running beautiful. Head 235, suction 65. Has a txv. Sc = 12 Sh = 25. Haven't checked air temp. Suction line was very cool & sweating, which it never did before. Started up nice and quiet. Amps dropped to 50. Sounds much better. Thanks again for all the help. Oh by the way this was my first semi-hermetic changeout - and my first comp changeout above a 5 ton.

[Six]

Does that 06d have an unloader ?

And if it has a mechanical unloader did you check the cut in and cut out SPs

Hell even if it has a electrical unloader it operation needs to be confirmed.

I always try to run down what killed the comp in the first place.

It might have slugged on start-up if it had internal mechanical damage.

I have a couple of 06ds in an old theater that were put in in 1974.

Still pumping.

Carlyse 06Ds

[tonydykes55]

The old one had unloader. I wasn't sure if there was a problem with the old one or not so I called manufacturer. He explained that depending on how the system was set up determined whether it was needed it or not. He said if the suction ever ran low the unloader would keep the pressure up. That's what I understood. I haven't hooked it up. It came width a sleeve that holds the valve open, if I'm correct, in the event that an unloader is not installed. That is how I left it. I'm glad you brought this up. Can you tell me more about it? Should I install it and if so how do I check it's operation? There is a low pressure switch.

[Push It]

I would most certainly hook it up if it had it OEM. I will let one of the more experienced guys on here help you with the set up but they will need to know if it is electric or pressure. If it is electric I would not trust that is is already set up right either.

Did you check the oil level again. If you had oil stuck in the evap cause of the failed compressor you will be over charge once it comes back. I would check for acid also due to they way you described the oil color. A high acid drier might of helped you out here also.