SMEV oven hard to light

Brittany Dogs · 08-24-2012, 06:20 AM

When I picked up my new TrailManor last year, the dealer made the comment "wow, I have never seen that oven before" meaning that at the time, the oven/stove was a make and model he has not seen before in the TrailManor units. OK my oven/stove is a SMEV which I believe is a foreign company under the Dometic parent company. The model is a CU434 and a search on the web only got me close but no cigar.

Here's my problem. When new the oven started up fine. It uses a sparker starter and does not have a pilot light. The instructions say to turn the oven knob to "light" and push it in while pressing the sparking button. The thermocoupler would allow me to release the knob after say 8-10 seconds.

Then this year my 10 seconds started to turn into 30 seconds, then a camp out later, maybe 60 seconds, then another camp out later, 2 or 3 minutes. Finally on my last trip, 8 minutes later of pushing the knob in, no joy, the oven just would not stay lit if I released the knob.

So the obvious first check should be the thermocoupler right? I cleaned it and that did nothing. The flame while I push the knob is normal, as good as it was new.

So I pulled the whole oven/stove out of the cabinet and found out that the whole unit is held together by about 30 pop rivets. Almost nothing could be disassembled unless I start drilling out a heck of a lot of rivets.

This is the part that gets FREAKY!

After turning the whole unit on its side, oven door down, to use a flashlight to look at the gas control knob inside and the burner assembly, then turning the oven on its side, to do more of "how am I going to fix this thing??" I felt a repair is useless unless I'm back home with more tools to remove 15 of the 30 rivets.

So I put the whole unit back into the cabinet, reconnect the main gas line and guess what?

The oven lights as good as new. And has now been lighting as good as new every time during my 10 night trip. I can release the oven heat knob after maybe 8 seconds.

The only thing I realistically did was turning the oven on two different sides, pointed a flashlight inside of it looking at the controls, and replaced the oven back into the cabinet.

It broke all by itself. I guess it can fix itself too. My magic flashlight is for sale for $1500 or best offer.

Does anyone have any ideas how this 14 month old oven fixed itself?

**Bill** · 08-24-2012, 07:32 AM

I suppose that there might have been some grit in the gas orifice. That would disrupt the gas flow, and the gas-air mixing. When you jostled the oven, it might have dislodged the grit.

Other than that, two possibilities, neither especially likely, but the best I have.

1. The thermocouple position is critical. If the mounting screw is a bit loose, it might have slowly vibrated out of position as you traveled, and your attempts to clean it could have moved it some more. Then when you turned it over, it came back into place. Incidentally, the thermocouple must be fully bathed in the pilot flame - and yes, there is a pilot.

2. As this group discovered a couple weeks ago, proper gas pressure is critical to the operation of the oven. The high pressure in the propane tank is reduced to 11-inches water column by the regulator mounted on the tanks. The stove/range then has a built-in regulator that further drops the pressure to 10-inches water column, mostly to stabilize the pressure. If either regulator is mis-set to too low a value, the oven won't work well. Could the oven's regulator have been mis-set, then reset by the jostling? Possible, though I find it unlikely.

Anyway, I'm glad all is now well.

Bill

Brittany Dogs · 08-24-2012, 09:34 PM

Thanks Bill. Good points to consider.

This particular oven does not have a pilot light. It uses a spark ignighter that is activated by pressing a momentary switch. The thermocoupler is otherwise positioned over the burner once the gas lights. Once the oven temperature selector knob is set to off, the flame goes out. There is no pilot that continues to be lit.

In fact, there is an "and" switch that is activated only when the oven door is fully open which allows the sparker to work when pressing the momentary sparkler switch. This prevents the oven cavity to fill with gas and then using the sparkler to light off the burner. In other words, the oven door must be fully open and the momentary switch pressed in order for the sparker to start sparking.

I have always felt that things just don't fix themselves despite my attempt at humor in my original thread. We'll see how well the oven works on my Labor Day camping trip.

gmferg · 08-25-2012, 09:02 AM

I believe the pilot that Bill is talking about is on only while the oven is on. When thermostat is satisfied, main gas supply is shutdown but the pilot stays lit. When temperature drops below thermostat setting, main gas supply kicks on again and is lit by the pilot.

Brittany Dogs · 08-25-2012, 09:53 AM

OK, this is more clear now. My apologies for not catching that understanding about the pilot.

Brittany Dogs · 09-01-2012, 03:31 PM

It is doing it again. After the travel of 320 miles back from my last trip and camping this weekend, the oven refuses to light. The burner is producing a good as new flame and the thermocouple is clean and fully bathed in the flame. No matter how long I hold the knob in to light the oven, when I let go of the knob, the flame goes out.

I am suspecting the end of the thermocouple that attaches to the gas flow knob assembly and the contact there that it is NOT making.

I just can't get to it.

**Bill** · 09-01-2012, 04:47 PM

Before you start ripping into things and spending money, I really suggest that you get an RV place to check the gas pressure in the main line, and again inside the oven.

Bill

09-02-2012, 06:42 AM

The only component that actually has moving parts is the switch on the oven door. With the door open look and listen to see/hear if there is an arc being generated. If not open and close the door or manually push and pull the switch if you can, see if the arc returns. I think this test can be done without turning on the gas. I am betting on the door switch not working every time and many just have come loose. Any screws or nut visible for this function??

Brittany Dogs · 09-02-2012, 12:53 PM

If I understand the function of the door switch, it allows the arc (sparker) to ignight the burner when I press the main sparkler switch. I have no problem ignighting the burner, just keeping it lit once I release the temperature push knob. It use to be that I could release the knob after 8 seconds or so and the flame would stay lit.

Billy's suggestion is a great next step and not very expensive to do.

Brittany Dogs · 09-29-2012, 06:24 PM

Update:

I called Dometic and the customer service rep didn't even realize they made ovens. But when I gave her the brand name and model number she learned something new that day; by golly they did buy a company (SMEV) that makes ovens and cook tops.

Dometic was no help. The rep said that any technical assistance is only extended to service technicians at RV dealers that have a super secret code (my words, the real term was "dealer service number" or something like that).

The LPG pressure in my feed lines appears to be fine since no other gas devices have problems and the flame on the stove and oven are as good as when the oven was new.

The problem remains that the thermocouple is not allowing me to release the bypass function of the oven control knob and keep the flame lit despite the thermocouple being plenty hot.