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11-04-2012, 09:21 PM #1Regular Guest
- Join Date
- Dec 2009
Grounded Copeland Hermetic New Install
2 months ago I installed a 1HP 3Ph 404a walk in cooler. I did a test run for 2 days, no problem. Unit was shut down, today construction of restaurant is over and inspector coming tomorrow (health inspector). Owner turned all the stuff on but the cooler didn't work. I found the compressor grounded, what did it? I shut it down (2 months ago) from a pump down switch inside the cooler that shuts down the solenoid and fans. In the mean time we had a bad storm around here, but owner said they didn't lose power. I will replace compressor in the morning, but I just don't want to believe that **** happens. So, any suggestions? Voltage is good all across, protector was opened and never reset itself, I bypassed it to see what happens, nothing happened, I was getting voltage all across 3 terminals but no amperage, that's what makes me scratch my balls, breaker didn't trip, all connections tight, no acid, I kicked (boot kicked) the compressor, checked for ground and now was no more. I checked resistance and I had none across 2 winding terminals (must've moved brains out of the comp with my kick). What happened here? What caused it to get grounded in off cycle? Any suggestions would be nice, would really jump start my brain, I ran out of ideas, Thanks and cheers guys.
11-04-2012, 10:07 PM #2
it happens..... single phased maybe.... who knows......it was working.... played with it.... now its broke.... whats the going hourly rate for HVAC repair
11-07-2012, 10:47 PM #3Regular Guest
- Join Date
- Dec 2009
Here is what I found: at the compressor we have black yellow red terminal wires. the black goes through an external overload, there is also an internal overload. I followed the wires to the main electric panel. This is a 3 phase panel feeds are black red blue. What I did find was at the breaker the wires didn't correspond to right color: had red to black, white to blue, black to red. I rewired the breaker so I have from the main feed black to black, red to red, blue to yellow all the way to the compressor. I have to learn more about the phase thing (panel wise), but so far I believe that was what went wrong, wrong voltage to compressor winding, like I said, I have to look more into this for the future, any suggestions? I replaced compressor and it runs as was intended to, nice all around.
11-08-2012, 07:40 AM #4Professional Member*
- Join Date
- Oct 2002
Coplawelds recips can run either direction. Coplamatic, I believe, can run in either direction too, but once run in one direction, it doesn't do well when reversed.
Copelawelds depend on refrigerant to cool the motor,coplamatic doesn't. So extended pump down will overheat the motor. Maybe a leaking solenoid?
12-08-2012, 01:19 PM #5
How many wires in the panel?
3 or 4?
What is the voltage measurement from each leg to ground?
Red to Ground = ?
Black to Ground = ?
Blue to Ground = ?
White to Ground = ?
The reason I ask is that if someone played with the power at the panel and switched a powerleg for a neutral, then the compressor pumped down due to eventual pressure buildup to activate the pump down circuit/LP Control, compressor could have single phased and possibly shorted to ground.
It's a stretch but the "white to blue" statement has me wondering...:what:
12-08-2012, 01:37 PM #6
12-08-2012, 02:35 PM #7
If you truly think it was a power issue and want to make sure it doesn't happen again, add a phase monitor to it. Won't take very long and save you a ton of headache.
12-08-2012, 02:46 PM #8
12-08-2012, 03:42 PM #9Professional Member
- Join Date
- Jul 2011
- Lehigh Valley, PA
3p 208 I am assuming? I do not think what you found is the issue. L1, L2, L3 can be wired in any order at the compressor so why would changing the wiring at the breaker make a difference? In addition, you are saying you have a grounded compressor. But you are not tripping the breaker. What is the resistance reading from the motor legs to ground? I think you have an open windings in the motor. Not a short or grounded compressor. (In fact, you compressor better be grounded.) Otherwise you would trip the breaker. What were the resistance readings across the compressor terminals? This is basic electrical troubleshooting.
12-08-2012, 09:01 PM #10Mistakes are a part of being human. Appreciate your mistakes for what they are: precious life lessons that can only be learned the hard way. Unless it's a fatal mistake, which, at least, others can learn from. Al Franken, "Oh, the Things I Know", 2002
12-08-2012, 09:22 PM #11
I assume there were builders in the place for the duration who would have liked nothing better than a nice cold room to store their lunch and cold drinks in.
If you're going to leave a room for a long period of time under the described conditions, do yourself a favour and pump the machine down from the receiver outlet valve, valve off the suction service valve at the compressor and disconnect power from the condensing unit and lock off or at least tag off the isolator.
That way if you return to the site and find the tag / lock gone and or the valves open, you know that someone has been playing silly buggers and sorry, no warranty.
no resistance across 2 winding terminals as in the ohm meter read 0? Or do you mean you had infinite resistance between the 2 terminals? (as in no circuit)
And once more, as you weren't there for 2 months and only switched it off at the fan switch in the room, you have no way of knowing if it was off or not. Particularly when the afore mentioned storm came through and you only have yourself to blame for that.
Hope that helps. Oh, and you may want to get some powder for that itch.Mistakes are a part of being human. Appreciate your mistakes for what they are: precious life lessons that can only be learned the hard way. Unless it's a fatal mistake, which, at least, others can learn from. Al Franken, "Oh, the Things I Know", 2002
12-08-2012, 09:37 PM #12
Out of curiosity, when you found the old compressor not working, was it hot?
And is it a scroll? What's its model number?Mistakes are a part of being human. Appreciate your mistakes for what they are: precious life lessons that can only be learned the hard way. Unless it's a fatal mistake, which, at least, others can learn from. Al Franken, "Oh, the Things I Know", 2002
12-08-2012, 10:05 PM #13