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Topic: if your water heater won't light... (Read 444 times) previous topic - next topic

if your water heater won't light...

...and the red light on the switch by the kitchen sink doesn't even light up, open up your water heater bay and check the brown wire which goes to what Foretravel calls a "thermal fuse" ...but I might call it a "limit switch" ...but whatever you wanna call it, carefully unplug the brown wire from each side of it, look to see if it's clean and has a good connection, then plug it back in ...and suddenly you've got power to your water heater controller again ...careful not to break the little fuse / switch when unplugging and plugging the brown wires in.
Scott Cook
1991 U300 36' 6V92TA
Old Town Penobscot 16
1984 Honda VF1100C (V65 Magna)

Re: if your water heater won't light...

Reply #1 –
Propane water heaters have a "thermal fuse" on the hot wire controlling the heater. This fuse will blow/open if the fuse gets too hot, usually from a run-away flame that does not stay in the burner. These are inexpensive, often sold two to a package and once blown must be replaced if you want the thermal protection. The location of the thermal fuse must be placed near the burner to have it do any good.

We have several thermal fuses in series that are located above and near the main burner to try to catch a run-away flame.

Last year, we decided turn off our propane shut-off valve when traveling, mainly because we now have an electric refrigerator. Well, because it was something new to our routine, we forgot to turn propane tank back on before turning on our hot water tank propane heat. The low-pressure residual propane gas allowed an ignited flame to flow up over control board and melt most of the 12-volt wires.

So now we have thermal fuses trying to prevent this accident. And we don't turn propane off anymore.
 

Re: if your water heater won't light...

Reply #2 –
My water heater started to do that too when I first bought the coach, mainly because the previous owner hadn't used it for so long the mud daubers plugged it up. When I tried to light the water heater the first time the flame backed out of the burner and started melting some of the wiring and the corner of the plastic control box. I cleaned the burner and adjusted the secondary air and now it works pretty well. I notice that it burns better at high altitude, even though I have the secondary air damper closed as far as it'll go. Eventually I'll get some of those insect screens to put over the water heater and furnaces. I haven't gotten the front furnace to run properly yet and the rear one doesn't even try to spark. After I get those running I'll put the insect screens on. It hasn't been a high priority as you can tell.
Scott Cook
1991 U300 36' 6V92TA
Old Town Penobscot 16
1984 Honda VF1100C (V65 Magna)