Dometic MA-52 gas valve?

Jabba · 02-07-2008, 10:00 AM

Hi,

Posting for a future project (read warm, snow free weather), our fridge does the usual thing for a 2-way, works only one way, which happens to be via electric. I can get the gas to light, but noticed no difference in flame height or anything when adjusting the t-stat. It does not "rumble" while burning or anything, just a standing blue flame with no cooling effect. Any ideas? If this is indicative of a bad control, does anyone have a similar fridge they are junking that would like to part with the gas control? I'd like to make an attempt to get the gas side to work before springing for a new fridge.

Thanks!

eubank · 02-07-2008, 12:00 PM

As I recall, our MA-52 pretty much kept the same level of flame all the time. Once in a while, we could hear it blowing, but mostly it was silent.

I can't say why it doesn't cool on propane. The big tube above the flame also contains the heating element for electrical operation. If the tube is heated by electric, it should also heat with the flame. Oh .. unless you've got some kind of stoppage up the tube. Did you check that?

Boy, I sure wish we had the MA-52. It's a larger fridge than currently available, and it was durned reliable. (That is, until it pooped out completely after many, many years.)

Lynn

Inland RV Center, In · 02-07-2008, 12:12 PM

Quote:

Originally Posted by Jabba

Hi,

Posting for a future project (read warm, snow free weather), our fridge does the usual thing for a 2-way, works only one way, which happens to be via electric. I can get the gas to light, but noticed no difference in flame height or anything when adjusting the t-stat. It does not "rumble" while burning or anything, just a standing blue flame with no cooling effect. Any ideas? If this is indicative of a bad control, does anyone have a similar fridge they are junking that would like to part with the gas control? I'd like to make an attempt to get the gas side to work before springing for a new fridge.

Thanks!

Clean the reefer flue, and make sure the LPG pressure is between 11 and 13 inches of water column pressure. Actuall, a setting of 12 inches works great.

Next, VERY carefully remove the burner and oriface. Carefully clean them as well as the base of the burner.

You will find rust particles in them that prohibit proper cooling.

CAUTION: Be very careful with the burner, as that part is no longer available.

Also remove the spiral from the flue and clean it as well.

Testing the flame should be done at night time or in a darkened building. Changing the thermostat from minimum to maximum, will not show any difference in daylight.

At maximum, you should also hear a very slight "roaring."

If the reefer cools on electric, then following the above will make it cool on gas, provided the reefer freezer plate is level, within 1/2 of a bubble.

Andy

Jabba · 02-08-2008, 07:37 AM

Thanks for the walk thru Andy,

I had vacuumed/blown out the flue as best as I could. I cleaned the orifice in place but will disassemble it completely as you described and try it again. I had run the "spiral" up and down to clean the burner flue, but will pull it and clean it as thoroughly as I can. One other question, what should the flame height be after I clean it? If my memory serves me correctly it was about 1" high. Pressure should be good as the stove and furnace work great. Will look into doing the water column check too.

Inland RV Center, In · 02-08-2008, 08:33 AM

Quote:

Originally Posted by Jabba

Thanks for the walk thru Andy,

I had vacuumed/blown out the flue as best as I could. I cleaned the orifice in place but will disassemble it completely as you described and try it again. I had run the "spiral" up and down to clean the burner flue, but will pull it and clean it as thoroughly as I can. One other question, what should the flame height be after I clean it? If my memory serves me correctly it was about 1" high. Pressure should be good as the stove and furnace work great. Will look into doing the water column check too.

To properly clean the flue, remove the spiral.

Wrap a coat hanger around some steel wool.

Run that steel wool from the top to the bottom of the flue, several times.

Clean up the spiral, and reinstall it.

Flame should be not quite 1 inch, "in the dark."

Andy

eubank · 02-08-2008, 01:10 PM

YEs, as Andy wrote, you take out the spiral and clean with some kind of implement. (Ours had a brush, a really long one.)

Once you clean out the flue, you'll probably find a pile of debris below it, right on top of the gas orfice. You could cover the orfice while brushing; that might help. But a good vacuuming afterwards won't hurt, either.

Lynn