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Rfriebert · 06-26-2016, 09:28 AM

I'm about to rip my hair out.
I have 2 Dometic HP on my 2008 Cayman (13500 units). The forward unit is fine but the bedroom unit will just run the fan, no compressor. Do i googled everything I could find under the topic and tried them all to diagnose. I'm wondering if anyone out there has any experience with these units.
Model 630035.331 Low profile Penguin HP
Have dual zone CC thermostat. This unit is on zone 2. Zone 1 works just fine with the front HP.
Problem: In either AC or HP mode, only the fan runs, compressor will not kick in. Fan will continue to run in either low or high speed fan. If I put into auto, the fan will shut down by itself after about a minute (still no compressor).
Tests:
1. Took out the capacitors and test. Run capacitor tests fine. Start Capacitor tests fine. PTCR on start capacitor looks fine and tests fine when left on capacitor for testing.
2. all coils look clean
3. performed a compressor "scratch" test and it looks good.
4. took leads off the compressor and did the
common to start = 0.90
common to run = 7.6
total = 8.5
start to run = 8.2 (not sure if this difference is substantial enough to consider compressor bad).
5. checked all wiring on roof top for breaks. No problems found. re-seated all connections.
6. check connections in control board (it is located inside the coach above the filter assembly in the ac unit). Unplug thermo RJ11 cable and reconnected. Fuse is fine.
7. performed an reset on the CC thermostat, no impact.

all that I can think of left is;
a.) the entire control panel may be bad but don't know what to check
b.) Compressor has a reversing switch on it but don't know why that would impact power (i assume it would be stuck in one direction)
c.) there appear to be two sensors on the walls of the coach. One up front and one in the bedroom. Can these go bad and cause an issue?

i would take it in for service after all this but I want to give it one more attempt in the event that someone comes up with something else for me to check. Besides, finding a decent Dometic service place around me is nuts (cleveland OH)

Any help would be greatly appreciated. i'm sure there are some HVAC techs out there that might welcome this challenge.
thanks in advance,
Ray

lass · 06-26-2016, 09:42 AM

I can't help with the diagnosis but if you go on the Dometic web site, it will have a list of certified mobile techs who will come to you.

The initial fee should be about $50 for their travel and inspection.

This is what I did.

YC1 · 06-26-2016, 09:59 AM

Those things on the wall are the remote thermostat sensors. Most likely that is.

I doubt they would keep it from running. I don't understand some of your measurements but are you getting 120 vac to the compressor motor?

Are you connected to 50 amp shorline? If not, it could be your load shedding is taking it off line.

As far as a reset, try turning off your battery banks and disconnection from shoreline for a few minutes.

walt2137 · 06-26-2016, 10:45 AM

Ray try a reboot on the thermostat it may help.

For 5 button reset:

SYSTEM RESET
1. Turn the ON/OFF switch to OFF position.
2. Simultaneously depress and hold the MODE and ZONE push-buttons while turning the ON/OFF switch to ON. FF should appear in the LCD display until the MODE and ZONE push-buttons are released.
3. When a dip switch in the system control board is turned ON or OFF after initial configuration, a system reset will need to be done before the Comfort Control Center will recognize the updated selection. See figure 11.

For 4 button reset:

a. Turn the ON/OFF switch to ON. The display light with
data should come on. If the light and data are not there,
see Section B2 Cable Assembly.
b. Depress mode to activate display light.
c. Depress the bottom two buttons (up & down) together.
d. While still holding the two buttons add the third from the
bottom (mode) , hold all three for a few seconds.
e. Release the third (mode) button.
f. Release the bottom two (up & down) together.
g. Depress the mode button. The display light should be
off. If not, repeat steps 2 through 6.
The control should return to the default setting of 68oF for
heating mode and 72oF for cooling mode.

96 Wideglide · 06-27-2016, 01:12 PM

Quote:

Originally Posted by YC1

Those things on the wall are the remote thermostat sensors. Most likely that is.

I doubt they would keep it from running.

I agree Myron. I had an issue with the remote thermostat on my mid AC. The AC simply ran constantly till I shut it off. Unplugging and re-plugging the thermostat back in solved the issue.

Rfriebert · 06-29-2016, 07:10 AM

Just want to send a big thanks to all that responded. Being completely new to the world of RVing and this community, I am blown away by the amount of people that just jump in and help. I'm in the software industry and I rarely come across this type of support environment.
Looking forward to full timing in about a year. thanks for all the help!!!