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jhenschen · 08-03-2010, 09:20 AM

We took our '67 Overlander out for the first time this weekend and discovered that the OE Dometic fridge won't cool. Wait, let me back up a bit. When we went to pick it up from the PO, he had everything plugged in and working. The only problem with the fridge was that the gasket was bad and the door was a bit wonky. I replaced the gasket and made new hinges. Now the door seals perfectly.

However... when we got to the campsite, we plugged into the power, turned on the A/C and then tried to start the fridge. I followed the directions precisely and after waiting about 30 minutes, noticed that it wasn't cooling at all. So I fiddle with the knobs, etc. and after about 15 minutes my wife says that she flipped the switch to ON and wondered why I hadn't done that. I swore I'd left it in the ON position, but oh well. So we wait another 30 minutes and open the freezer door and its obviously working. Its pretty darned cold. So we're happy. I go back in an hour later to get a drink out of the freezer and its warm in there again. *sigh*

So I give up with that. I decide to try out the propane option. I follow the directions, get the little pilot light lit and knowing that the propane option can take a while, we wait about 3 hours and nothing. Not cold in the slightest. So we go to bed and about 8 hours later I check it again. The pilot light is still lit but its still not cold inside.

What am I missing here? I read in a previous post that weak batteries could be the problem for the electric option. I know my batteries are weak and need to be replaced. In fact, I noticed that when the air is on, one light is on and I try to turn on the radio, no sound issues forth. However, if I turn off the light, I get sound, but the radio display dims. I assume this is battery power issue. Could this be the fridge issue as well? I turned off all of the lights and turned the air down to low during my last electrical fridge test and it didn't seem to matter.

So while weak batteries could be the fridge culprit, could that be the propane problem? I didn't think using propane used electricity, but I could be wrong.... Any help would be greatly appreciated. Thanks!

NicheVintage · 08-03-2010, 09:35 AM

In our 65 we had the same issue. I will say it takes ours around 24 hours to cool off whether on propane or electric. As for the electrical make sure it is properly wired the Po on ours had the wires backwards and it didn't work. It may work on yours just needs more time to cool down.

Good luck

jhenschen · 08-03-2010, 09:46 AM

The thing is, I know the PO didn't have it connected for more than 4 or 5 hours before we came to pick it up, and the fridge was working just fine on shore power. *sigh*

richinny · 08-03-2010, 12:23 PM

can you tell us the voltage from the 12v ssystem?

what is the model number of the fridge?

what do the lights on the fridge display say?

are any of them flashing?

are the 12v lights in the trailer dim?

jhenschen · 08-03-2010, 12:32 PM

I'll have to check on the current voltage... its currently in storage.

No lights on the fridge, its too old. It's a Dometic MA52a from 1967

I assume your asking that if I have the AS running solely on the batteries, are they dim. I would would have to say yes. I know for a fact I need new batteries. The last time I manually charged the batteries, they had a charge of something like 12.06. However, I have a professional battery tester and the units recommendation was to replace the batteries.

I guess my lack of understanding of 12 volt systems combined with a 110 volt system is my problem here. I would have assumed that once you plug in the trailer to the 30amp shore power, it shouldn't matter if you have weak batteries or even NO batteries. Am I wrong in my thinking?

richinny · 08-03-2010, 12:59 PM

from what i know from reading here. if you light the gas fridge manually then you don't have a board so 12v doesn't matter.

if plugged into 120v AC shore power, a seperate coil heats the ammonia used to cool the fridge.

on lp gas, the gas burns to heat the ammonia.

in a 3-way fridge, a 12v dv coil heats the ammonia.

the fridge needs to be very level or the ammonia gas will not properly circulate and cool the fridge.

an initial cooling of the fridge can take 5 or so hours to get much of a chill in the coils.

in my fridge, the freezer coils feel cold before the main section.

so, where are we now? :-)

jhenschen · 08-03-2010, 01:23 PM

Ricky,

Well, right now we're at you being awesome for helping me. Oh, you mean in the fridge situation. *smile*

Yes, we have to light the fridge manually on propane. And where we were was not precisely level. So, if it has to be very level for it to work on both shore and propane power, that may be part of the issue.

I bought the "Managing 12 Volts book by Harold Barre a few days ago and have been poking through it today. I think a lot of my problems will be solved with new batteries. Luckily, I know a trade secret that will get me deep cycle RV batteries for $28.95. COntact your local Exide distributor and ask them what kind of unlabeled batteries they have in stock. They're batteries that have been on their customers shelf for 6-12 months and after that, Exide brings them back, removes their label and resells them at a fraction of their cost.

RichHog · 08-07-2010, 10:59 AM

The above info is all good about your fridge and system. Trailer must be level for the older fridges to work. You can open the back panel behind the fridge and feel the heat from the electric coil or from the propane. If it heats and trailer is level then the ammonia will flow and the fridge will cool. It will take several hours before you will know. It is a sealed system so if there is any yellow color or powder on the piping then you have a leak. If not then there may be a blockage in the flow in the pipes. Sometimes that shakes loose in travel or you remove the fridge, turn it upside down for a day or so and try it again, a process called "burping". Burping didn't work for me so I chunked the fridge on mine.

Typically you power the trailer up a day or so before departure to charge battery and cool fridge down off electricity. Then load it up with your stuff and switch it over to propane so it stays cool during travel.

Dr Dan · 08-07-2010, 11:18 AM

The level deal is huge, "it can't be more than 4 degrees off level" I was told after removal of the unit, hauling it in to a shop, only for them to plug it in and have it work. Of course I only had to haul it home and replace the wall and all the other easy fixes that are involved with re installation of units that are not broken! But I try to look on the bright side. I WILL NEVER FORGET THAT IT HAS TO BE LEVEL.
Good luck,

RichHog · 08-08-2010, 07:59 AM

Fortunately the newer Dometics aren't quite as sensitive to that.

TG Twinkie · 08-08-2010, 12:32 PM

I have posted a number of threads in response to others having cooling problems with the older model refers. Check out my posts and replies.

jhenschen · 08-23-2010, 12:50 PM

Okay... this time when we took her out, I made sure the trailer was super level and the fridge worked right away. Then again, I'd also replaced the batteries with two group 27 deep cycle's. Not that those seem to make any difference. Unplugged, the AS has no power even though there are two new batteries installed. It worked before on battery power... briefly... but now, with the batteries in place exactly as the old ones were, nada. It worked when plugged into the shore power, but nothing when under battery power alone. But the fridge worked well and quickly, so its a start.

Wabbiteer · 08-23-2010, 02:06 PM

The day I brought my '73 home I had a similar problem - many fuse-to-holder grip area contacts were open circuit from a thin layer of corrosion; removing, cleaning and replacing ALL the fuses, the primary quick-disconnect. and the wires at the fuse block terminal clamps had everything back up in a short time

Shacksman · 08-23-2010, 02:22 PM

Quote:

Originally Posted by jhenschen

Okay... this time when we took her out, I made sure the trailer was super level and the fridge worked right away. Then again, I'd also replaced the batteries with two group 27 deep cycle's. Not that those seem to make any difference. Unplugged, the AS has no power even though there are two new batteries installed. It worked before on battery power... briefly... but now, with the batteries in place exactly as the old ones were, nada. It worked when plugged into the shore power, but nothing when under battery power alone. But the fridge worked well and quickly, so its a start.

Just so you know, the batteries have nothing to do with that fridge. It only works on gas or 110 electric. Some newer models need 12 volt to operate.

TG Twinkie · 08-24-2010, 07:44 AM

If it works on propane, I would check the heating element. It is probably a 150 watt heater and is located on the right rear side of the refer, behind a metal shield that is just above the burner. There will be 2 wires connected to it. It just slides down inside a metal tube. When in electric mode, (make sure you rotate the knob or flip the switch to electric) then make sure the "electric" thermostat is set to at least 5. The wires are terminated at the rear as well. If you can, check the voltage at the terminating point, it should be 110-120 volts AC. You do have the trailer plugged into shore power, right? If you don't have AC power at the terminals, make sure the refer is plugged in. there should be a 120 volt outlet in the compartment behind the refer, it's probably mounted high and will probably be kind of hard to reach. I think you said you had to light the refer by hand so there is no 12 volt system on this unit. Keep us posted on your progress.

TG Twinkie · 08-24-2010, 07:58 AM

I posted a photo of the controls on my refer. Go to my posts and look for the date 6/07/10. Do your controls look like this?

jhenschen · 08-24-2010, 08:26 AM

TG Twinkie - Thanks for the help. The fridge seems to be working fine now that I make sure it's *extremely* level. And I checked your pics of the controls and mine look nothing like that.

I also understand that the fridge won't work on 12V power. However, nothing is working on just the 12V power. No lights... nothing. Its supposed to, right?

Wabbiteer · 08-24-2010, 09:09 AM

Quote:

Unplugged, the AS has no power even though there are two new batteries installed. It worked before on battery power... briefly... but now, with the batteries in place exactly as the old ones were, nada. It worked when plugged into the shore power, but nothing when under battery power alone.

Quote:

However, nothing is working on just the 12V power. No lights... nothing.

You need to use a voltmeter or a 12V circuit tester (small lamp in handle of something looking like a small ice pick w/ one lead) and ring the circuit out - was there a quick disconnect that did not get 100% seated? Move on to main fuse, fuse box, etc...

wasagachris · 08-24-2010, 09:22 AM

Your whole trailer runs on 12VDC power with the exception of the air conditioner and 110VAC outlets in the walls. You have a power convertor that changes 110VAC (shore power) to 12VDC when plugged in. When unplugged the battery will provide 12VDC to the lights, water pump, furnace fan etc. If you are towing and you have a charge line installed on your tow vehicle the cars alternator and battery will supply 12VDC to the trailer to recharge the battery. Your old style fridge does not need 12VDC to run a control circuit board because all controls are selected manually. I hope this information clears up the mystery for you.

Shacksman · 08-24-2010, 10:24 AM

Quote:

Originally Posted by jhenschen

TG Twinkie - Thanks for the help. The fridge seems to be working fine now that I make sure it's *extremely* level. And I checked your pics of the controls and mine look nothing like that.

I also understand that the fridge won't work on 12V power. However, nothing is working on just the 12V power. No lights... nothing. Its supposed to, right?

If nothing is working on 12V then you have a bad ground connection from the battery to the trailer frame. Try putting a wire from the negative battery to the frame.
I just fixed this on another 67 trailer. There are 2 fuses in the battery line, one on each cable. One was broken, replaced and everything worked.