Thermocouple for Royal Dometic?

[MATTY J]

Hi guys,

My 78 Dometic frig is not lighting. I have attempted to light from the back at the thermocoupler with no go. I am assuming this needs to be replaced. Does anyone have leads on replacement thermocouplers. Our storage lot repair guy confirm as well, but can't locate the part.
Royal Dometic
Model# RM100
Ser# 731 1422
Prod# 9264302

Any info is greatly appreciated!

[larry b]

Matty
does your fridge light when you hold the button in on the gas valve?

[TG Twinkie]

A new universal thermocouple is available at most hardware stores. Just pick one that has a capillary tube that is as close to the original as possible.
Try this: disconnect the capillary tube at the point where it connects to the top of the gas valve. Be careful and don't lose any parts. Clean the contact point inside the valve as well as the contact on the end of the "c" tube. Re install it in the top of the valve. While holding it firmly in the valve, tighten the nut. Don't over tighten it. Try this before you buy a new one.

[MATTY J]

Originally Posted by larry b

Matty
does your fridge light when you hold the button in on the gas valve?

First I am not able to light the fridge from inside the trailer, the only way I was able to light it (when it worked) was from outside. I light it at the couple manually with a lighter.

Now it won't light at all, when holding down the gas valve. It won't light or hold a flame.

Thanks guys!

[TG Twinkie]

Are you sure you are getting gas to the burner?

[MATTY J]

Originally Posted by TG Twinkie

Are you sure you are getting gas to the burner?

I am a rookie when it comes to trailers. When I couldn't light it at the coupler, I went back and light the water heater and stove with no issues. I don't know how to check if the frig gas line might be blocked.

Thanks
Matt

[TG Twinkie]

It takes quite a while to get the air out of the gas line. Maybe you should give it another try. There could be dirt in the gas valve which would require removing and cleaning.

[idroba]

If it won't light at all, the thermocouple is not the problem as it is bypassed when you hold the (usually) red lighting button down. If it lights, and will not hold the flame on after the red button is depressed for 30 seconds or so, then you might have a thermocouple issue, but it sounds more like you have no gas at the refrig, or a clogged orifice in the line or something of that nature.

[MATTY J]

Originally Posted by idroba

If it won't light at all, the thermocouple is not the problem as it is bypassed when you hold the (usually) red lighting button down. If it lights, and will not hold the flame on after the red button is depressed for 30 seconds or so, then you might have a thermocouple issue, but it sounds more like you have no gas at the refrig, or a clogged orifice in the line or something of that nature.

Yes no light at all + no gas. Any tricks on unclogging? The stove lights right up, The water heater is a little more ticky but will always light and stay lit.

[Mikethefixit]

Mattyj
I found a thermocouple for my1977 Water heater on ebay, (hardtofindrvpart) is the store. He also had the exact replacement for the valve had I needed it. He is in Northern Indiana. I think around the SouthBend/Elhart area. He shipped fast and his price was very reasonable. He did communicate good also.

[idroba]

I would first crack the nut on the copper input line to the refrigerator and see if there is gas that comes out there (careful, no, no sparks, electric etc.). If there is no gas there, be sure that the valve is on, under the trailer.. the valve on the line to the refrigerator. Work back to the valve and as far as necessary to find where the gas is blocked.

If there is gas at the refrigerator (hissing sound and smell when you crack the nut on the input) I would next check the small brass orfice which is at the beginning of the sheet metal tube that goes to the actual burner. It can be screwed out and cleaned with alcohol, but never ever use anything else like a drill or wire to try to clean it. While you have the burner out, carefully check the tube itself and the screened burner top for rust or any spider webs. Clean it with compressed air. Yes, spider webs can stop the burner from working and are not always easily visible, so shoot it well with compressed air.

Someplace you will find the problem of no gas to light.

[eubank]

My guesstimation is this: Even with a crummy thermocouple, it should light; it just won't stay lit because the faulty hot thermocouple is not sending the appropriate signal to the gas valve.

After a while, a good deal of small debris can fall down the heating tube right onto the top of the little pilot burner, enough over time to cause it to fail. Turn it all off, and try cleaning out the area with a good vacuum. (We use a store-bought reducer connected to the vacuum for this kind of thing. It increases air speed and directs the vacuum right where you need it.)


Lynn

[MATTY J]

Originally Posted by eubank

My guesstimation is this: Even with a crummy thermocouple, it should light; it just won't stay lit because the faulty hot thermocouple is not sending the appropriate signal to the gas valve.

After a while, a good deal of small debris can fall down the heating tube right onto the top of the little pilot burner, enough over time to cause it to fail. Turn it all off, and try cleaning out the area with a good vacuum. (We use a store-bought reducer connected to the vacuum for this kind of thing. It increases air speed and directs the vacuum right where you need it.)


Lynn

Thanks, makes sense it's not lighting. I will check it out.