Newbie A/C question

[billhenry58]

Hello,
I’ve got a new-to-me 2005 25’International. It has a Dometic Penguin II a/c (I think). When we bought it in the fall (still warm weather), the a/c blew strong and cold. We just took it out for a 3 nighter and the a/c didn’t work. It would hum, but no fan or cooling. The literature in the AS manual is very inadequate for the a/c and talking to Dometic on the phone had me thinking of violence (the rudest most useless person I’ve talked with in awhile). Anyhow, it’s an un-ducted unit with two knobs. One controls the fan (low, med, high), cooling (low, med, high) and also optional heat (not sure if I even have that). The second knob is a temperature control (warm to cool). The breaker is 20 amp and not tripped. I’m hoping I have a stupid simple solution like a switch I don’t know of? Also, I assume the Atwood thermostat is for the furnace only? Thanks in advance!Any suggestions?

[Belegedhel]

Well, the humming-but-not-starting is usually a dead give-away that your start capacitor is shot or weak. There are other possibilities, like maybe a family of rats has built a nest in the fan area and it is keeping the fan from turning. Also, this could happen if the juice coming in from shore power is not up to snuff (ie., voltage is low). I assume you were plugged into a proper 30 or 50A power supply, not trying to run off of a household 15A circuit.

One thing to try would be to remove the shroud and ensure that the fan is moving freely and that no debris/rodents have collected up there. Next, I would say find a source of shore power (other than the one you used recently) and try it again. If you can't even get the fan to spin in "fan only" mode, then it is very likely your start capacitor is the problem, since many of these units have a start capacitor that is shared by the compressor and the fan. The replacement part is less than $20, and you can do the replacement yourself if you know just enough about electricity to stay safe.

good luck!

[billhenry58]

Thanks for the quick response. I was hooked up to a 30A campsite, but didn't have a meter to test the power. It's a fairly new campground so I would expect it was ok, but you never know I guess. I'll be taking the shroud off this weekend and checking further. Thanks a bunch! I'll not mention the rat comment to my wife, that would be the end to a very short camping lifestyle.

[Belegedhel]

Rat, squirrel, chipmunk, sometimes it is hard to tell--but I just had a friend with essentially the same symptoms, and it was the start capacitor, so I guess sometimes they fail for no discernible reason.

[cwf]

Don't keep trying to "start"'the AC!!! Start checking problems. Careful.. this can injure or kill you... you accept all responsibility in your actions.

If the fan won't run... may have animal damage or obstructions. Remember, rodent droppings are a serious health concern...

To check interior fan for obstruction ...

- shut off power
- Remove plastic "air distribution box" from ceiling... (instructions online)
- try spinning the squirrel cage
- if turns free, power unit on and observe (don't touch) the squirrel cage as you turn on "fan only"
- runs ok?

Now, check compressor part..
- Turn control to "A/C" low.. this will run the compressor (only one speed, no high or low)... does the compressor "hum"?
- turn off AC, remove power, check wiring connections in the AC electrical box
- if all wires ok, check voltage (turn on breaker of course)
- carefully check voltage while AC is trying to start (humming). If voltage drops it may be a frozen (broken) compressor. That will be bad.

Lastly, if all above is ok... the Cap (capacitor) may be bad.

WARNING! The Cap can have life threatening voltage even when defective.. DO NOT touch any terminal without insulated tools!!!

This will require a trip to the roof. Before you jump up there, consider buying a cap before you proceed....to save trips up and down.

- power off by circuit breaker
- remove the cover on the roof side (put in safe place.. best to hand to something ne on the ground)
- verify the fan turns easily
- visually check Cap.. if swollen, it is likely bad...
- with Circuit Breaker Off or trailer unplugged (double check). Use a screwdriver to "short" across Cap terminals to discharge.
- carefully remove one wire at a time from cap and connect to the new cap. It IS important to plug correctly..
- remove old and replace with new Capacitor.
- leave cover off and have helped power up and retry AC... if it works, power off and replace cover... enjoy.

If uncomfortable with these steps, take to a dealer or call out a "mobile tech"!!

Hope it is just a buncha mice made a home or a loose connection...

[billhenry58]

ok. I brought it home from the shop today. Turns out that the fan motors wouldn't turn. The technician stated that they had sorta seized due to light rust from sitting unused too long (all winter). They freed them up, lubricated them a little, cleaned the unit and we are good to go!

[cwf]

Might help to get an AC cover for winter prep