ReplyThe 0.5 amps on the aux winding is way low. My 3.5 ton scroll pulls 7.0 amps. A fractional hp motor might pull 0.5 on the aux winding. All the other theories you have are thin...check the wiring.Originally Posted by Butch1234
Professional Member*
DIY at it's finest!!!! 6 freak'n compressors. All under warranty i assume!!!!!They probally gave him 2 replacements. Then he had to buy the 3rd and maybe the 5th and 6th!!!!
Professional Member
The 0.5 amps on the aux winding is way low. My 3.5 ton scroll pulls 7.0 amps. A fractional hp motor might pull 0.5 on the aux winding. All the other theories you have are thin...check the wiring.
Regular Guest
I agree,,,,, my calculation show that this should be maybe 2-3 amps to a maximum of 7 amps depending on voltage drop across the capacitor (which I will measure) using the following formula one can calculate the expected current in the start winding
C in MFDs= (2654 * Amps)/voltage. where the voltage is the voltage drop across the capacitor...so perhaps this is the problem
no these are not under warranty...the folks that sold this system went out of business...I am the bag holder...
once we figure this out I will post a long story on this system...I appreciate constructive ideas and suggestions....we keep you posted
Professional Member*
Voltage drop across the capacitor? I'm confused!!!As i always read higher voltage across the capacitor!!!!
Professional Member*
Is this a french system?
Are the in ground pipes plastic coated copper?
AOP Committee/Professional Member*
2654 is the value used in a 60 hz system. Are you using 60hz?
[Avatar photo from a Florida training accident. Everyone walked away.]
2 Tim 3:16-17
RSES CMS, HVAC Electrical Specialist
Member, IAEI
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Professional Member
He's no doubt, from Missouri...
Regular Guest
What is the Model number of this unit
What is the complete Model number of the compressor.
What is the total holding charge of refrigerant in this system.
What type of oil are you using.
What is the level of oil in the sight glass when running and when it is off.
What is the temperature of the sump of the compressor and what is the suction pressure.
Have you checked oil for contaminants and has an oil analysis been performed.
What is the Model Number for the Sporlan CPR valve.
What caused the previous compressors to fail and where they opened up to examine failure.
What is the superheat and sub cooling.
Did you install a crankcase heater.
Have you installed a suction clean up filter and how did you clean up the mess.
__________________________________________
Trouble shooting is not part of the repair......understand the symptoms and you will find a solution.
Professional Member
LOL he still hasn't checked voltage yet!!
If You Can Dodge A Wrench You Can Dodge A Ball
Professional Member*
@ butch1234
What is your understanding of the function of a CPR valve?
You say you adjusted it.....do you realize there is a specific way to adjust these valves? You cannot just start cranking around on the adjustment and hope it solves the problem because it won't.
Professional Member*
He won't answer questions so don't waste your time. He won't even post the model # of the compressor.
Regular Guest
yes it is 60hz 3540 Vac
but more importantly
FIXED !!!!!!!!!!!!!
First I want to thank everyone on this board who gave constructive ideas. As most of you know, when you are dealing with a very perplexing problem it helps to have knowledgeable folks to discuss the problem with. Yesterday, after several posters suggested that the current in the starting winding of the compressor was too low, and my own calculations also confirmed that it should be much higher I went back to take another reading of this motor lead. As I stated before, the first time I took the reading with a clamp on, the meter was up under the control panel part of the unit in the shade and it was difficult to see, I thought I read 0.5 amp but it could have been 5 amperes, I just was in a hurry at the time. Well I went back and checked, this time I got an even lower reading (~0.3 amp !). I looked the wiring over one more time and could see nothing wrong. But I figured I will just replace a short (~10”) factory lead from the secondary side of the contactor to the run capacitor.
[Digression …years ago I was working as a startup engineer on two 750 Mw coal plants in MN, we had a large coal conveyor that brought coal into both units that kept tripping. The startup engineer responsible for coal handling was going nuts trying to solve the tripping problem (he was a mechanical engineer by training). Anyway the coal conveyor would run for a day or so then trip, then restart and run for a few hours then trip. No one could figure out what was wrong. Finally I said I would come out and look (I was a backup on this system but had too many other problems to worry about this, if you have ever been involved in starting a large power plant you would understand). Anyway I went out and spoke with the electricians and looked over the control circuit and everything they had tried and I could not think of anything different. Finally, I said well we got to start replacing every wire in this control cabinet. So they replace 3 or 4 “critical” wires in the circuit and we restarted the conveyor and it ran fine. After several days still no trips so it looked like we had fixed it. After a few more days with no trip we all figured well it is fixed and we all had too many other problems to worry about it. However, one of the electricians had the original wires at his work bench and for the heck of it hooked each one up to an ohmmeter and started wiggling them. And BINGO, one of the wires had an internal break that was not apparent to anyone. They called me to the shop and we all looked at each other and agreed that we had found the problem. One of the guys took an EXACTO knife and scraped the plastic insulation away from the spot where we felt the break was. And we found a clean cut in the stranded wires. How that occurred is any body’s guess, but what was happening is the two ends touched enough so when you measured the resistance it showed zero (good continuity), but when current tried to flow the circuit would occasionally open (the reason switch contacts (e.g. relays, starters) all have mechanical pressure on the contacts to make sure they are held tightly together). We only found the problem by replacing wires and as a last resort.]
So after I replaced this short lead I restarted the unit and it ran smooth. I knew the minute it started that it was working fine. Indeed, the starter winding current was now about 10 amps (the voltage across the run capacitor was about 319 volts, the current agrees with the formula C in MFDs= (2654 * Amps)/voltage, or 80 *319/2654 = 9.6 amps). And the total unit draw was about 24 amps (66 psi suction about 300 psi discharge hot water mode). No more rattle and the correct current. Anyway looking at the wire it looks fine, the connectors (spade female end (slide on)) look fine but there is obviously something wrong with the wire. I want to show this wire to a few folks and eventually we will see where the break is. This was a factory installed wire and as I said, when you look at it you see nothing wrong. I did not spend a lot of time trying to figure out where the problem is but it is obviously intermittent. It measures 0 for resistance (i.e. good continuity) so I suspect there is an internal break that opens when current tries to flow. Anyway, never look a gift horse in the eye, for now the unit is working the way it is supposed to.
When I have some time I will write a long long story of what it has taken to get this geothermal system working. Again thanks for all the help you folks provided.
Regular Guest
type 240 vac
Regular Guest
typo it is a 60 hz 240 Vac system, the model number is ZR61 PFV 950 if my memory serves correctly, in any case thanks for all your suggestions
AOP Committee/Professional Member*
Your fix story is a good example of why one can never assume the wiring is good.
It also underscores the chesnut that Arthur Conan Doyle wrote for his character, Sherlock Holmes, that "... when you have eliminated the impossible, whatever remains, however improbable, must be the truth..."
[Avatar photo from a Florida training accident. Everyone walked away.]
2 Tim 3:16-17
RSES CMS, HVAC Electrical Specialist
Member, IAEI
AOP Forum Rules:
Professional Member*
Also shows why you need to hire a tech. This would have been found and fixed in about 10 mins several compressors ago.
Regular Guest
this did not cause the other compressor failures...as I said it will take a long time to describe all the alterations that we have done to fix this system. Some techs are good some just want to sell you parts. I do not know many who understand this type of system. Few have experince with anything but simple split systems. Sorry that is the way it is in this part of the country.
Professional Member
I got lots of respect for engineers. Had I gone to an engineering school, I might well have been one. But what isn't taught or learned in engineering classes, is all the empirical knowledge one acquires doing service work in the field.
Had one of the experienced guys here been with you, they would have instinctively measured the auxiliary winding current early on, saw it was non-existent, then looked for the cause and discovered the open conductor...in a matter of minutes. You, however, assured us in post #6 that the wiring had been checked, re-checked and couldn't be the problem.
Next time somebody tells you to check the wiring...
Check the frickin' wiring!!!
Professional Member*
And this is not a DIY thread? A service tech andy service tech would have known .5a on a run cap. for a compressor is too low and would have gone the distance to find out why. Not just to SELL YOU PARTS that you you don't need. As if you needed 6 or however many compressors. I like my Industry to be insulted by the homeowners that CAN FIX ALL OF THEIR OWN STUFF becouse we either charge to do the work, are not smart enough to figure out the problem or asre out just to rip people off. Nice Butch1234. Glad you figured it out I guess we should follow your example and become an engineer so we can fix HVAC systems faster and easier.
dogboy
Regular Guest
I learned a long time ago to never argue with a fool, people will not know the difference. Actually, the three lead motor currents were measured several weeks ago and were presented to the manufacturer's "expert" on these compressors and he had nothing to say. I suggest you review Copeland literature and perhaps you can find a place where they discsuss the various currents. When asked about this, the factory rep said that the current was measured in the common leg (black in this case) and when asked what the component parts should be he had no idea. Yes someone might have spotted this problem sooner....but at the time I posted this several days ago we had already fixed several other issues and this one was nagging. The contractor that installed the system did not know because his "manuals" are silent on these readings.
I thank those that gave suggestions....as far as opinions we all have them...second guessing is fun but not always productive.,...thanks
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