True-Air compressor #2-help!

Izzyblueye · 02-04-2005, 04:31 PM

Need some advice. While running my heat pump the other morning, everything was running fine. Both compressors were engaged. Wife turned on an electric skillet. The "on line energy mgmt system" shut down switcher started making stuttering noises. I shut the heat pump down. Noise stopped, now compressor #2 doesn't engage under any thermostat setting. #1 is running OK and it is heating. I have reset the breakers. Is there an inline fuse or breaker that may have tripped? All other systems are working OK. Even if I can't fix it, I would like to know what it might be. I'm on a 30 Amp system. Appreciate any input.

Izzyblueye · 02-04-2005, 04:31 PM

Need some advice. While running my heat pump the other morning, everything was running fine. Both compressors were engaged. Wife turned on an electric skillet. The "on line energy mgmt system" shut down switcher started making stuttering noises. I shut the heat pump down. Noise stopped, now compressor #2 doesn't engage under any thermostat setting. #1 is running OK and it is heating. I have reset the breakers. Is there an inline fuse or breaker that may have tripped? All other systems are working OK. Even if I can't fix it, I would like to know what it might be. I'm on a 30 Amp system. Appreciate any input.

DriVer · 02-04-2005, 05:25 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Homer:
Noise stopped, now compressor #2 doesn't engage under any thermostat setting. #1 is running OK and it is heating. <HR></BLOCKQUOTE>This is curious and counter to what was told to me by the Mach people at Louisville.

They said that when the unit is in heat pump mode that both compressors will run. Question I have is will the unit provide any heat on only one compressor?

I've been running mostly electric heat here for about a month. Running furnace below 40 but so far that's been rare. I have to admit I do believe that the 50A service does give me a lot of flexibility especially when I'm running everything but the stove off of electric.

BucknJeff · 02-04-2005, 07:29 PM

The first thing I suggest you check is the incoming voltage from the park pedestal. Once it is known, start checking it in the coach at outlets (presuming the inverter is off), and look for relatively the same levels. If everything is over 115V, and stable, then consider below.

If you are very comfortable with working on line voltage electrical, I would suggest disconnecting the coach from power, and shutting down the inverter. Once all power is off, remove the cover of the circuit breaker/Energy Management System main panel (where the circuit breakers are.)

Next, use a screwdriver to loosen the set screw on the circuit breaker, and remove and inspect the wire. Note if the set screw seems loose when you begin to unscrew it. Be certain that the wire, and lugs are clean. If they are at all "burned" or discolored, trim away a little wire so that clean copper is exposed. Next, reinsert the wires and be sure they are good and tight. Also, I'd check the neutral buss bonding to be sure that its tight as well.

Then, CAREFULLY, and only if you are certain you know what you are doing with 220 volts, and with the cover still off, re-connect the shore power. With a multi-meter, check the voltage at each A/C compressor circuit breaker, where the wire leads out of the breaker, and note the voltage. On 30 amp service, and with everything else on the coach off (don't forget the fridge) the voltage readings should be very close. IF they are, go ahead and start the heat pump, and check the voltages as each compressor starts. IF the second compressor attempts to start, or there is any "funny noise" in the circuit breaker box, quickly check the voltage at the #2 A/C breaker, and then shut that circuit breaker off. If the voltage remains constant while the second compressor attempts to start, the trouble may be in the A/C unit. If, however, the voltage drops more than say 10 volts from the other compressor for more than a few seconds, or drops off, or behaves oddly in any way, the issue is with the power supply or the EMS system. In my experience, EMS failure is very rare.

Next, I would begin to trace the power path back to the pedestal, paying VERY close attention to the transfer switch buss bar, giving it the same inspection and re-torque as the circuit breakers. Many times, this is the problem.

Hope this helps.

Izzyblueye · 02-05-2005, 03:26 AM

Driver & Buck & Jeff: I am getting pretty good heat out of the system on heat pump. Not as good as it was. I am basing my determination concerning #2 compressor on this fact, I am not pulling the number of amps that I was previous to the malfunction. I am now pulling about 16 amps with nothing else running, previous pull was 26. It does not shut down power to the w/h, which it did previously. It never did kick the breakers at the main breaker panel. I will follow as much of Buck & Jeff's suggestion as I am comfortable with. I should not encounter 220V any where, but I treat 110V with a great deal of care. Do either of you or any one else know of a sure fire way to determine if # 2 is running, the distribution panel shows power is going to it. Which makes me suspect of yet another fuse or breaker. Thanks for your help.

BucknJeff · 02-05-2005, 04:00 AM

Homer,

Thanks for pointing out that you are, in fact, only on 110V due to the 30 amps. I guess I was tired!

Indeed, you are only running one compressor. While the amp load varies by line voltage (slightly), 16amps is only one of the compressors. If you have not already, perhaps you should check the coach 110V circuit breakers and be certain they are on by flipping them off and then on.

Aside from that, I'd check the voltage at the breakers.

Hope this helps.

DriVer · 02-05-2005, 04:23 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Homer:
Do either of you or any one else know of a sure fire way to determine if # 2 is running, the distribution panel shows power is going to it. <HR></BLOCKQUOTE>Absolutely! You can meter each leg off the main panel with an induction meter and directly read the amps on the instrument. See if you can get your hands on an Amp Probe

Cruzer · 02-05-2005, 06:13 AM

The EMS shouldn't be making a stuttering noise, it's electronic. The stuttering noise may have come from a relay on the heat pumps themselves but another possibility is the transfer switch.

My 2003 Suncruiser 33V's electrical system had the 2nd A/C (or heat pump) compressor breaker on the "Y" side of the breaker panel. All the other breakers were on the "X" side of the panel. On 50 amps the X phase feeds the majority of the breakers while the Y phase feeds the second compressor. There are two seperate contactors in the transfer switch to handle this. When you plug into 30 amps, the 30-50 adaptor wyes the 30 amps to both sides of the breaker panel (after passing through the transfer switch). It is possible that the stuttering you heard was the transfer switch and the contactor that feeds the "Y" side (your 2nd compressor) is no longer making contact. It's something you may want to check out also.

Izzyblueye · 02-05-2005, 12:20 PM

I really appreciate all of your help on this problem. Today, with my limited electrical expertise, I believe I have confirmed the 2nd compressor is not kicking in. It tries, but can't sustain a start. #1 is working pretty good. I also noticed the system is activating the gas furnace on the first start up nearly every time. Even at 71 degrees outside, that is a new twist. I can and do fake it out by doing a second start. Tomorrow, I will check into the transfer box under the cabinets with the power off. I'm also thinking the transfer solenoid has taken a hike. Cruzer, my unit is basically the same unit you had, except I am restricted to 30 amps. This is the first time I have ever had a problem with the True-Aire system, I think it is the best part of my coach.

RKL2 · 02-05-2005, 01:56 PM

Homer...pay close attention to resetting the circuit breakers...I popped one last week and just flipped it back to on...result...Still didn't have power at the outlets....got down on my hands and knee on read the circuit beaker instructions on the breaker iteself....guess what I learned....you have to push it further down (off) and hold it there for a few seconds and then flip it to on....tried it and it worked....ist time ever having to flip a coach breaker...my house breaker just go from off to on without having to press them further off.....don't know if this is your problem, but know I can't run both compressors on AC or HP with just 30 amps, especially if my water heater and/or refrig are on electric.....good luck RKL

coopcolt · 02-06-2005, 02:37 PM

Let me see if I can add some cornfussin?
My 02 Adventure with 30amp. service, has never
done a really cool job, say at the NASCAR Bristol fall race. I took it to the local
winny shop [thats another story] in 03, THEY said it checked out OK, current draw and such.
I was using the genset in 03, Genset HOT air is being sucked into the air cond, and I have a full mud flap in the rear. I try to keep the flap tied up, so as to move the gen air and also the HOT air that is being generated from the A/C. Now we have to move cold air from the basement to a hot attic and cool a 33ft.
M/H on a 95deg. day in full sun. What is wrong with this picture??? The OK check cost $176.

Now for todays thread, I started the Genset, 6.5KW and turned the H/P on, [I know that if the set temp is 4 or 5 deg. higher than the room
temp. the gas furnice will lite off.] So with a 3deg. differance the H/P drew 11 to 12 amps, and for five minutes it drew the same amps.
as if the other #2 comp. did not turn on.

I also have 20amp. line in the RV garage
for lights and to charge the batteries, so I set the same conditions and both compressors came on line, as the amp. draw was 25-26 amps. Only let it run for 15 or 20 sec. and shut it down!

Now is the only differance the transfer sw.?
We will leave for Fla. wed. and when I get to 30amp
service I will check her out!!!

Thank to the powers that be for this and the OTHER
RV site!! Coopcolt

Izzyblueye · 02-06-2005, 03:34 PM

I took the cap off the transfer switch today and found next to nothing to observe. A small plastic relay and nothing else but a couple of wires. I do know it is one heck of a place to access, you work through 3 drawer openings. Took cover off EMS center also, checked slo-blow fuse, it is OK, not smart enough to check all the leads in and out. Will try to find a qualified tech for that.

Coopcolt, it is my understanding when using the Genset, EMS panel meter will not reflect the amp draw of # 2 compressor, doesn't need to, there are plenty of amps available. This was explanation given to me by Winnebago tech. Some one on this foum, with greater electrical credentials than I, might give you a more specific answer.

Buddy & Jenna Kidd · 02-07-2005, 06:44 AM

If compressor #2 tries to start but can not then I would look for a start capacitor as the problem. I had one go out on me. It is located in the box on the left side of the A/C unit. You have to raise the grill to get to it.

Izzyblueye · 02-07-2005, 07:20 AM

BUDDY & JENNA KIDD: I have contacted a certified RV tech right here in the park to look at it. One of the items he mentioned was a start capacitor. It will be a couple of days for him to get to me. I will post back as to what the problem is. Thanks for your input and the location of the start capacitor, that helps.

Cruzer · 02-07-2005, 10:35 AM

Homer,

The EMS system utilizes a transformer pickup coil that wraps around the neutral line from the breaker panel. All amperage that is fed into the system on 20 amp shore power, 30 amp shore power, or generator power must go through this coil so your ammeter will always read the full amps being used. The EMS itself will shed loads in either 20 amp or 30 amp shore power modes but will not shed loads when running on the generator set because the genset can put out plenty of amps. The genset will properly display those amps on the EMS meter though, even though they are not regulated by the EMS.

However, when you are connected to a 50 amp shore power the ammeter will be blanked out and the EMS system will be inactive. When ever you connect to a 4 pole 50 amp service the full current load does not pass through the transformer coil, only the difference between the two phases, therefore it would never be accurate so it is blanked out.

Izzyblueye · 02-16-2005, 01:24 AM

The problem with compressor was found and we are up and running full power again. There was a wire loose on the relay going to #2. The wire actually burned. All capacitors and starters were checked. All electrical values were checked according to specs. Everything appears to be in great shape. The tech feels this loose wire existed over a long period of time, and finally burned the wire. Thanks to Airexcel for furnishing all the specs and schematics for doing the job. Thanks to everyone on this forum who offered your help.