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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have a coleman mach 6536A871 rv basement heat pump. The unit

Customer Question

I have a coleman mach 6536A871 rv basement heat pump. The unit appears to be running with slight cooling, but in only drawing 7 amps per energy management panel. When it first starts, it is drawing 14-15 amps, but settles down to about 7. Specs indicate running should be about 14. I am running on the generator. Should I be concerned with the low current draw?
Submitted: 2 years ago.
Category: HVAC
Expert:  Phil replied 2 years ago.
Welcome! We keep going until you have all of the information you need.[b/]. Extensive training & coaching also available.
set the thermostat on cooling and down to 60F, then tell me what the temperature at the cold air vents, and tell me what the temperature is at the return air grill.
So far it sounds like there is a refrigerant leak.
We can go from there.
Customer: replied 2 years ago.
Startup current 14-15 amps and drops to 11 amps steady until second compressor starts, then drops to 8 amps. Temp at cold air vent about 58 and room temp is 68. Also, compressors are making a pulsing sound as they run.
Expert:  Phil replied 2 years ago.
Hello again, your amp measurements are not making sense. I want to take a different approach.
Make 100% sure that you have set the thermostat to 60F for this test, and open the door to the RV.
Both compressors should be running, each compressor has 3 heavy power wires attached directly to spade terminals on the compressor marked C, S and R.
Check the amp reading on each of those wires *separately for each compressor and do it after the compressors have been running for 3 minutes. Write down the color of each wire and the amp reading you got.
Next feel the fattest copper tube attached to each compressor tell me if it is warm, cool, or sweating.
You will have to remove one or two service access panels to access the compressors to do this.
Amp reads taken at the power connections for the AC will not do us any good.
Let me know about all that, we can go from there.
Note: I will be at the dentist getting a root canal starting in 15 minutes then back later in the day to pick up your response... I will be in until 10 pm midwest time... and all day tomorrow.
Customer: replied 2 years ago.
Will have to wait to get information. Relative to answer that did not make sense, one piece of missing info is that while on the generator, only ac unit 1 is going through the energy management system. Second ac unit is not visible unless rv is plugged into external 30 amp power source.Also, will not be able to check copper tubing for relative temperatures as this ac unit is a "basement ac" by Winnebago. Can pull unit, but trying to understand issue before deciding to go this route. You can google to understand why.
Expert:  Phil replied 2 years ago.
Hello again, so far we have not gotten to any sort of an answer... I am still digging for the information I need to get you one.
I have worked on these before, accessing the compressors is not at all easy, neither is diagnosis without getting to the compressors... its a tough situation.
Any attempt to diagnose such a complex system from here is more than a long shot, I will opt out in case there is someone else here who wants to attempt it.
Ihis situation will be difficult even for one of the best HVAC techs that Camping World or other RV shop has on staff..
Customer: replied 2 years ago.
Was able to get some of the information you requested. The wiring is tight and short, but I think the numbers highlight a problem.Comp 1: 5.9 A on line into control circuit. 2.3 A on common line.
Comp 2: 8.9 A on line into control circuit. 5.5 A on common line.Does this limited data help. Also looks like next stop is the AC shop. Comp 2 looks better. Until I get it into shop, could I bypass Comp 1 and control Comp 2 with Comp 1 circuit? Scary question right.