Rear HVAC compressor will not come on Suncruiser 37F

bobder41 · 06-27-2015, 12:51 PM

On my coach I have the thermostat calling for cooling on the 2 zones. The duct fan will start for both units and the front compressor. The rear compressor and fan will not start on the unit. I breakers are on since when I flip the rear one off its fan duct motor turns off also. My question is on a roof top unit with the ducted system how do you get to the junction box or controls of the unit. I'm pretty sure Coleman would not design a unit that would require removal from the coach to check it out.
Coleman heat pump Model 47073a879 13500 BTU

Thanks in Advance

grtharris · 06-28-2015, 08:05 AM

bobder41, on top of the coach remove the outer cover then the inter cover and you will find the connections. Note I have cleaned up the wiring. The 4 x 4 box setting down in the duct is a delay unit to keep both compressor from starting at the same time on power up only on the rear unit.

bobder41 · 06-28-2015, 08:46 PM

Thanks again for the help. My rig was built 12/14 and it must of been built the last day before Christmas vacation.
Some interesting things I found.
There is a control box located under the condenser fan by the compressor. I found the wires loose on the relay that turns on the compressor and fan. The relay will sometimes stick and not make the connection to the compressor and fan motor at times. (will call dealer for another relay)
When I pulled the evaporator cover off like your picture, I found the front of the coil coated with Styrofoam so very little air passed through it. After I corrected these 2 problems I put everything together and ran it. After 30 minutes of running I noticed water dripping off the roof. So back up I go

and check the condensate pump line and could not blow through it. Looked around and found Winnebago did not trim the hose to length and it was kinked shut so it never could work. I fixed that and thought I was done.
Well when I went into the bedroom below the rear HVAC unit I found the ceiling fan blades where off the fan and on the bed with the nut, washers and snap ring washer that secures the blade assembly in place. As I was putting the fan back together my son went to use the rear bathroom and he couldn't close the door.

Checking it I noticed that the 2 screws that attach the door to the sliding hinge are missing and the only thing holding this end of the door up was the lock pin. I had to dig up to screws to fix the hinge.
Like I said it must of been built the week of Christmas. A lot of work to do to a new coach that I have owned 3 weeks and has less than 300 miles on from me driving it home from the dealer.

grtharris · 06-28-2015, 09:59 PM

bobder41, there was a lot of styrofoam on my evaporator coil in both units. And like I said I did a lot of work getting the wires cleaned up and out of the air flow. Was the delay box installed? I have a long story about the delay box. They starting installing them about two months after our coach was build. Without the delay the generator cannot not start both AC units at the same time. Which happens sometimes.
I cannot not believe some of the things I have found that were just not installed correctly.

bobder41 · 06-29-2015, 06:00 AM

Yes it has one it is running a 20 sec delay. We are taking it out for the first time on this weekend. When I get it home I plan on bringing a vacuum up there and cleaning up the Styrofoam in both units.

KWD · 06-29-2015, 10:31 AM

I have a rear A/c on a 97 Adventurer that will not run on shore power, but runs great on the generator along with the front unit, could that be the problem, is it the fact that it is a 30 amp system and it just will not pull two A/cs. Why on generator and not on shoreline?
______
KWD
1997 Adventurer
2008 Jeep Wrangler

bobder41 · 06-30-2015, 05:11 AM

something is preventing your unit from coming on. If you have an energy management system on your unit I would start there. My 2 13,500 BTU HVAC units when on pull 24 amps with nothing else on using a 30 amp service. It is possible that if you are pulling more than 30 amps at times kicking it out.
How many watts is the generator? What size HVAC units do you have?
Also you did not state that it use to come on when connected to a 30 amp service in the past or not.
Please let me know your answers and maybe we can help.

grtharris · 06-30-2015, 09:25 AM

KWD looks like with a 30 amp system you can only run one AC unit at a time when connected to shore power. There is a AC selector switch to choice which one you wish to run. When you run the generator one power leg feeds the breaker panel and the other feeds one of the AC units through the AC selector switch which must be in the front position to run both AC units.