Dometic Refrigerator Problem

[eddie1261]

When I plug in to shore power, does it override the 12v system? I ask because if I recall the shore power cord was plugged in when I was testing the fridge on propane. I DID hear the relay, and I know the propane is flowing, evidenced by the stove lighting. 

THIS stuff is why I appreciate you folks so much! All your experience really helps newbies learn.

 

[Kirk W]

3 hours ago, eddie1261 said:

When I plug in to shore power, does it override the 12v system?

I'm not quite sure what you mean by "override" but when you plug into shore power the RV has a converter that takes in 120V-AC power and puts out 12V-DC power to supply the on board loads and to recharge the batteries. That source when there will usually carry any 12V loads needing it even if the batteries are discharged or defective. 

3 hours ago, eddie1261 said:

I DID hear the relay, and I know the propane is flowing, evidenced by the stove lighting. 

I don't that you hear any relay but may be the ignition circuit making a spark to light the small propane flame. That flame is very small, on the order of a pilot light for most appliances and can be very difficult to see, especially in daylight. If you are getting an error light it is pretty safe to say that it isn't lighting. There are several possible reasons that could cause this to happen. You may want to try turning off the refrigerator and then apply the business end of a vacuum hose to the burner area to see if you can suck any debris from it since that could cause it to fail to light. 

[eddie1261]

1 hour ago, Kirk Wood said:

I'm not quite sure what you mean by "override" 

What I meant was when I am plugged in to shore power is there a relay that disconnects the coach batteries. But thinking about that, I see the answer is no because the shore power is 120v and the batteries supply 12v. So yet another "duh" on my part.

I will look to see if there is any place to stick a vacuum nozzle but I don't know what I am looking for when you say burner area. Let me pull the outside door off and see what I see. That "relay" I hear clicking is likely what you said, the igniter trying to ignite.

[eddie1261]

Okay so where's what I did today.

First to address batteries. They read at 12.96 with the shore power unplugged and no generator. Then I started the generator and they read 14.06 as the generator was juicing them.

The fridge. I went inside and with the propane off, I tried to start it on propane. In about 3 seconds I heard the burner try to ignite (or ignite as the case may be), after which I waited and watched. After about 30 seconds, the check light came on. I did that 3 times for sake of consistent results. (I had never seen that check light before because of how I tested yesterday.) Then I turned the propane on and tried to start it again. I heard the same sound of an igniter after about 3 seconds, and I let it go as long as 2:30 before stopping the test. The light indicating it was running on gas never came on, nor did the check light. Again I repeated that test, this time for 5 repetitions. The results were exact on all 5 tests.

I then pulled the outside cover off, and this is what it looks like. If this will let me upload another pic I sill show you a view looking up, though it may have to go in a second message for image space restrictions. Also note that the flue was warm, but it had been running on shore power so I expected that. Nope. Pic #2 in ext message.

 

[eddie1261]

..

[Kirk W]

4 hours ago, eddie1261 said:

So yet another "duh" on my part.

Not completely "duh." There is a connection between the 120v and the 12v in that your converter takes in 120v -ac power and puts out 12v-dc power to supply those loads and to recharge the house batteries. So there is a connection, but not directly and it doesn't remove the batteries but charges them. 

3 hours ago, eddie1261 said:

I then pulled the outside cover off, and this is what it looks like.

In that first picture, you can see the propane valve to the lower right with the solenoid on it. There is a label with an electrical schematic just above that valve. The rectangular metal box to the right of that is where the propane line goes and it contains a small gas jet to control the size of the propane flame which is probably at the top of that box, with the rounded sheet-metal tube above that being the flue. The boiler is inside of that flue area as is the burner where the propane flame should be and the black wires are probably to the electric heater that is supplied by 120V when cooling with that source. The electric plug on the far left side is the 120v power to the heaters and both propane and electric are controlled by the circuit board that is below and just to the right of the power plug. That board uses 12V power that comes from the terminal block just in front of it on the floor of that space. The tank you see with the barcode on it is the collection tank for the condensed refrigerant that then goes by gravity back to the boiler over in the flue to be heated again. The place to use the vacuum is on the bottom of the flue. You can get a good explanation of how your refrigerator works at this link. 

[eddie1261]

Great info, Kirk. First thing tomorrow I look at that post up close and personal and try what you said. And I will read what is at that link tonight.

[eddie1261]

Just to follow up, I vacuumed out whatever dirt might have been in there and nothing changed. Still will not run on propane, so when I have it winterized I will have them also check the fridge and furnace.

[Kirk W]

3 hours ago, eddie1261 said:

I will have them also check the fridge and furnace.

Looking at your pictures again, I wonder if you have considered checking that valve? If it were to fail & not open, you would have the problem you seem to have. Use your meter first to see if it gets 12V and then the ohm meter to be sure the coil is not open. You should be able to feel it snap open if you have someone to turn the refrigerator to propane for you while you keep a hand on the valve. 

[eddie1261]

Okay so is feeling is snap open related to my hearing something appear to engage when I switch to propane?  I have nobody to help me test to physically feel something on the outside when I have to be on the inside to turn the fridge on. Literally no friends who live close enough to ask to come here and help me. Closest person who would do it is 45 minutes away. I'll work it out.

In the meantime, is this where I am supposed to look for 12v?

[Kirk W]

Yes. If you pull the connectors and put your meter between the leads with the refrigerator set for propane there should be whatever voltage is in your 12V system between them. Once you know that, turn the refrigerator back off and measure with the ohmmeter between the pins of the valve with the leads still removed. It should read a low value of resistance. If it is 1000 Ω or more the coil of that valve is open(failed) and the valve is not supplying propane to the burner. The valve could also fail mechanically. Failure of those valves isn't common but I have known it to happen. 

[eddie1261]

Okay Kirk. With my fridge on and the leads pulled off that valve, they read 12.9VCD. Then I turned the fridge off and tested with the meter set for ohms and it read 50.

I also note that a small brass screw on that valve will rotate 45 degrees, from straight up 12 to turn to the left to 9. Apparently that must control the amount of propane going to the fridge. So I rotated it to full open at 9 o'clock and I could hear more gas hissing through it. I then tested the fridge again, and again, I hear the pop of the igniter, the fridge doe snot light, and there is NO check light. Just to make sure of that check light, I turned the gas off, tried to start the fridge again, and he check light came on. Apparently I am not getting a spark. It works great on AC. The flue is really warm, and the water in the jug is very cold.

[Kirk W]

33 minutes ago, eddie1261 said:

I then tested the fridge again, and again, I hear the pop of the igniter, the fridge doe snot light, and there is NO check light.

I must say that at this point, I am mostly guessing. I wish that WorkinRVer (Vern) would happen by to look this over as he is a certified RV tech who currently does RV repairs to pay his bills. As such, he might be able to think of something that we have not done. The pop you hear should mean that it is making a spark but you may want to trace the lead to the ignition probe and try removing it to clean it or perhaps observe if it is sparking. Have you removed the sheet metal cover to the right of that gas valve to look inside? That should be where the burner is located. 

[eddie1261]

Ignition probe? I have no idea what that is. And there is NOTHING online for this 17 year old RV. The support guys at Forest River don't even know because it's so old.  When you look online, there are like 25 different 2000 Sunseekers. I have no idea what I have, and none of them really give any definitive way to identify. Like most technical information, everything is written assuming you already know much about the subject vehicle. Many are like "Ok. First you buy a plane. Then you fly it." without ever touching on that pesky subject of "How to fly a plane".

I think I will just have it checked/fixed when I get it winterized. I don't know enough about this to be taking things apart and my wrenching skills are non existent anymore.

[Kirk W]

12 hours ago, eddie1261 said:

I have no idea what I have, and none of them really give any definitive way to identify.

The key is the specific refrigerator model and that information should be located on one of the labels you can see in the back and there is also a small schematic just above and behind the valve in your picture. It should say there, or nearby what model your refrigerator is. In most cases, there is also a plate on the inside of the refrigerator that lists the model and serial number.  Dometic models are things like RM 3612, MB52, or MA35,  etc. If you locate that information you can then go to Bryant RV Services: manuals and download a copy of the one for your refrigerator.

12 hours ago, eddie1261 said:

Ignition probe? I have no idea what that is.

That is the device that makes the spark to light the propane. It has a high voltage lead from the circuit board to supply power and is located near the outlet of the propane jet, downstream from the gas valve. 

[eddie1261]

This system seems to be double posting and there is no way to delete our own posts. Sorry for the double dip.

[eddie1261]

I can now say 100% that my issue is that I am not getting spark. I have voltage there, and I can hear that the gas valve is open because I hear the flow stop when I rotate it, and start again when I rotate it back. All of your help that guided me to the right place to troubleshoot should cut down on the dealership troubleshooting time and hopefully save me a few bucks. Thanks again.

[Kirk W]

12 hours ago, eddie1261 said:

This system seems to be double posting and there is no way to delete our own posts.

That is part of what moderators do. A participant can't delete his posts. Most forums do not allow that. There seems to have been some sort of problem in the servers since Hurricane Harvey, but the forum is hosted on an "off-site" host and there is only limited things which the Escapee IT department are able to do. I think it may be getting better? 

12 hours ago, eddie1261 said:

All of your help that guided me to the right place to troubleshoot should cut down on the dealership troubleshooting time and hopefully save me a few bucks.

I sure do hope that proves to be the case. If they will allow you to do so, try and observe when the tech checks things out as it will probably help you to know how those refrigerators are built. And do let us know what the tech comes up with.

[xctraveler]

On 9/12/2017 at 10:16 PM, Susieq said:

"Hi Eddie - I have been meaning to get back on here to tell everyone what was causing my problem and how it was finally resolved.  I needed new house batteries, so had 2 new 6V batteries installed while I was in Illinois, on my way to view the eclipse.  The batteries were old and I had neglected to water them, not realizing that they are like house plants!  The propane would work when I first started out and while I was driving, but not when I was parked without electric.  Evidently, it needs a certain amount of energy to ignite, and the batteries were not providing enough to re-light it each time it cycled off and tried to come back on.  I mentioned my problem to a man at one of the RV parks that I stayed in overnight, and he diagnosed the issue because it had happened to him many years ago.  Now all is fine.  I just have to remember to check the water level in the batteries periodically and add distilled water as needed.  I hope this information helps and that your problem is as simple as this!"

Just to briefly repeat what i have said before: Set a specific date once month to look at your batteries and check water levels. I do this on the 1st of the month, every month! Takes a couple of minutes to check and maybe 5 to top up with DISTILLED water if necessary.