Dometic/propane turns off when underway

heatlamp · 05-12-2016, 01:49 AM

When running on propane, the Dometic fridge on my 04 170 keeps turning itself off when the van is underway (I understand the official word is to use DC underway). It runs fine when the van is stopped.

At first I thought that this might be related to wind blowing out the pilot light, but this happens even when there is very little wind.

Reading though the forums, I see recommendations for similar problems to check/clean the burner tube and perhaps replace the thermocouple.

Any other thoughts?

Thanks, Jim

booster · 05-12-2016, 01:51 AM

Those are good recommendations, clean, check pressure, etc.

Blowing out while underway is very common and the motion gives plenty of wind to do it.

heatlamp · 05-12-2016, 02:26 AM

Thanks. This didn't happen with my last RV that had the same fridge (04 Pleasure Way), so something is clearly amiss.

eric1514 · 05-12-2016, 02:42 AM

Is the refrigerator on the same side of the coach as it was on your previous one?

heatlamp · 05-12-2016, 02:52 AM

Yes it is. Pleasure Way excel and RT 170.

eric1514 · 05-12-2016, 04:05 AM

Quote:

Originally Posted by heatlamp

Yes it is. Pleasure Way excel and RT 170.

Well, my reason for asking was that depending on which side of the coach the fridge is on, the burner might be less in the line of wind entering the vent. On my Class C, the fridge was on the pass. side and the burner was tucked up well out of the wind. On my Travato, the fridge is on the driver side and the flame is open to all the air that comes rushing in the vent.

If you've made sure that the flame is strong, you might consider what I did here: LINKY

booster · 05-12-2016, 01:24 PM

A Eric says, even which side of the van it is on can make a difference, and definitely there are differences between brands of class B. If the 04 170 has the same configuration of the vents as our 07 190 did, which I think it does, there will be 3 vents. An upper built into the window frame bottom, the lower removable vent, and a screened vent to underneath the van. Even things like the position of the side mirror or having the window open or closed can make a difference in airflow.

Lots of folks, with lots of different models, including the Chevy 170s, have had issues with blowout. Maybe half of them get significantly better after cleaning the burner and pilot, and adjusting the propane pressure to the high end of spec. For the rest, the solution that seems to work the best is some sort of airflow change, like Eric has done. Some have had good success with small spoilers at the lower vent edges, either front or rear. I would guess most everyone with a propane frig would have it blow out in extreme crosswinds, I know we did.

Best solution is to drive with on DC, but with some foolproof way to remember to turn it back to propane if you stop for more than a short time. With a single battery, the 170 will not run long on DC without the engine running.

eric1514 · 05-12-2016, 01:32 PM

Quote:

Originally Posted by booster

...
Best solution is to drive with on DC, but with some foolproof way to remember to turn it back to propane if you stop for more than a short time. With a single battery, the 170 will not run long on DC without the engine running.

That's the part I need to work on. Something simple that requires no input from me...like a seatbelt chime.

hbn7hj · 05-12-2016, 01:47 PM

That's the part I need to work on. Something simple that requires no input from me...like a seatbelt chime.

That is easy. Put a 30 amp relay in the line to the DC heating element controlled by the center tap on the isolator. (Alternator output) When the engine isn't running the DC is off.

A wireless temperture gizmo will tell you when you foirget to turn the propane on.

eric1514 · 05-12-2016, 01:59 PM

Quote:

Originally Posted by hbn7hj

That is easy. Put a 30 amp relay in the line to the DC heating element controlled by the center tap on the isolator. (Alternator output) When the engine isn't running the DC is off.

A wireless temperture gizmo will tell you when you foirget to turn the propane on.

I missed that day in school when they talked about relays and stuff so those kind of things are difficult for me. I'll have to do some reading to educate myself.

[Hijack] There's another "thingy" I want to design. If you turn on the propane solenoid in the Travato and then turn it off, there will be enough propane in the lines to run the fridge for over an hour. I'd like to design a timer circuit that would turn the propane on every 1/2 hour for 1 second instead of leaving the solenoid on all the time because the solenoid draws .7 amps per hour and I think my timer could draw considerably less. [/hijack]

avanti · 05-12-2016, 05:37 PM

Quote:

Originally Posted by eric1514

[Hijack] There's another "thingy" I want to design. If you turn on the propane solenoid in the Travato and then turn it off, there will be enough propane in the lines to run the fridge for over an hour. I'd like to design a timer circuit that would turn the propane on every 1/2 hour for 1 second instead of leaving the solenoid on all the time because the solenoid draws .7 amps per hour and I think my timer could draw considerably less. [/hijack]

Now THAT's an interesting and novel proposal for solving the infamous solenoid-amp-sucking problem. You could also put a small tank downstream of the solenoid to serve as an accumulator. This would give you control of the run time/refresh interval.

I've moved on to a compressor fridge, but if I still had propane, I would definitely consider doing this. You can get the timer you need on eBay for like 6 bucks, complete with relay.

eric1514 · 05-13-2016, 01:12 AM

Quote:

Originally Posted by avanti

...You can get the timer you need on eBay for like 6 bucks, complete with relay.

If you get the time, can you link a timer thingy on eBay for me? I have no idea what I should be searching for. I can start my education into this from there.

Thanks

avanti · 05-13-2016, 01:35 AM

Quote:

Originally Posted by eric1514

If you get the time, can you link a timer thingy on eBay for me? I have no idea what I should be searching for. I can start my education into this from there.

Here's one, chosen more-or-less randomly:

DC 5V 12V Multifunction Self Lock Relay PLC Cycle Timer Module Delay Time Switch | eBay

That link won't work for long, so here's an image:

timer1.jpg

You can find similar stuff on Amazon.

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