My coach has a 10 gallon water heater. The LP gas function quit recently. I have collected some parts to do an overhaul.

Inspection reveals 20 year old wiring, corrosion in general. In order for the gas valve to open, the ignitor must fire, and the circuit must be complete through both thermostats and the inline thermal cutoff. One thermostat controls the working temperature the other is a high temp cutoff. Both sense the water temp in the tank. The inline cutoff protects against flames around the controls.



The burner and spark probe ignitor are badly rusted, beyond cleaning in my opinion.



The two thermostats have corroded connections as well as the inline thermal cutoff. I'm pretty sure the connectors would break off the thermostats if I tried to remove them. Replacements are cheap.



Parts are easy to find, reasonably priced, and widely available. Except for the burner, the parts are interchangeable with the 6 gallon units.

Burner and spark probe:



Thermal cutoff and thermostats:



When the weather warms up I'll show the installations. (Actually this is the warmest day in 2 weeks, 18 degrees...) This will leave only the main gas valve and the ignitor PCB unchanged. Should run for a long time again, not bad for about $60.

Steve VW, What is the temperature rating on the two thermostats?

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I just purchased several thermostats for my fuel oil burner. The thermostats I am using to enable the fuel oil burner to burn Waste Vegetable Oil or Waste Peanut Oil. The little button thermostats look very similar. Are they made in China?

The working thermostat is marked 60 C, the overtemp is marked 82 C. (My chemistry students, Canadians, and the rest of the world would know that 60 C = 140 F and 82 C = 180 F) Rated 15A at 125V, normally closed.

I think they are bimetal switches made in China. I have similar normally open ones I've used for forced air furnace blower controls (around 130 F) and one for my motorcycle radiator fan at about 170 F.

The thermostat cycles, but it triggered, the overtemp has to be replaced, unless the design is different now.

Looks pretty much like my heater. Richard obtained, but never installed, an electric element for it, which he gave to me with the coach. I haven't looked into installing it yet and was wondering if anyone else has done this and how hard it is. I might go ahead and replace the burner while I'm at it/

The electric element should not be too much trouble. It is installed in a recess in the tank. I believe the element has its own thermostats. Once in place you'll need to connect to an on/off switched 110 power supply at about 15 amps.

Danny, I see you have 48 degrees, 12 degrees here this AM

Back when I "worked" There was a thermocouple salesman from a company that distributed some China made products, he had a bunch of round disc bi-metal pieces, he would warm them in his hand then throw a handful of the damn things on my desk, as they cooled they popped and flipped up about 3 foot. Pissed me off!!! Oh well time goes bye!!!

We in eastern Iowa had -1 at about 10pm last night, when I got up it was a heat wave of 5F now 12F...get the bikini!!!

Steve it is balmy there at 12 degrees. Minus 1 in Minnesnowta at 9 am with the sun shining.

Got the wood-burner going trying to warm the shed up enough to work on my new old boat and trailer. If it weren't for heated socks I wouldn't even try.

I had to cleanup all the connections to the water-heater. I hardly ever use the gas. I have the electric rod that screws into the drain hole. Works well. Unbelievable how much crud will accumulate on that rod. When I winterize I scrape it off and buff it with the wire wheel on the bench grinder until back to the Stainless steel shine.

Not to get too off topic, but if I needed to spend money on a water heater, I'd just can the whole thing and get one of the new instant hot water heaters now being used in a lot of motor homes. I don't know about anyone else, but I like long, hot, showers My next Barth will definitely have one.

Jim

quote:

Originally posted by Steve VW:
The electric element should not be too much trouble. It is installed in a recess in the tank. I believe the element has its own thermostat. Once in place you'll need to connect to an on/off switched 110 power supply at about 15 amps.
:

Usually it's a surface-mounted resettable 'stat.

My water heater went down last summer.

Appears to be the same heater as yours.

I had a major electrical failure a number of years ago and fried the board.

I replaced the board with an aftermarket "Dinosaur Board" at that time.

Are you getting spark at the probe?

I was getting spark, but no ignition.

From all the information I could find, the failure pointed to the Gas Valve.

After a ton of searching, I was UNABLE to locate an exact replacement valve as you have pictured.

I purchased the recommended replacement, but really couldn't figure out how to mount it with the existing mounting bracket.

After some "rigging", I was able to get it all back together and working better than ever.

Some adjusting with the Air Shutter will give you a nice quiet, blue flame.

I do believe the Gas Valve is a White/Rodger 93870.

After replacing:

Board
Drain Valve
Relief Valve
Thermostats
Burner Tube
Spark Probe
Gas Valve

...it may be prudent to find an entire replacement heater and replace the whole unit

-OR-

As recommended by some of you folks, just go with some form of tank-less unit.

Actually...

The Gas Valve I used was a 93845 (just went out and looked).

The Spark Probe obviously only needs one wire, so I snipped off the other.

The wire that came with the Spark Probe did not have the "spark plug style" connector on the end that attaches to the board, so I cut and spliced the old connector to the new probe wire.

I have the 6 gallon unit, but all hardware "looked" the same as in your photo.

Nice and warm in Forida now so I got back to the water heater. Replaced all the parts I had, it fired right up as expected.



It appears the valve is also bad, it does not shut off completely, slight flow. I will replace it soon. I mostly use the electric heater when I am plugged in anyway.

I disassembled the gas valve, cleaned the valve seats and it works fine now.

On my way home in April we noticed a burnt electrical odor after we parked and hooked up utilities. Noticed it once before but could not locate it.

I found fried connections on the inside 110V wiring for the heater element. A simple system, it has a heater element and two thermostats in series with the power switch. The thermostats are very similar to the external ones used for the gas system. (One for the working temp and one for overtemp protection.) Evidently the push on connections to the stats get corroded over time, heat up and melt the wires.

Since the thermostat spades were fried I replaced both stats, connectors and the wires. The 110V thermostat kit comes with both stats. (Atwood kit #91873, $13.99 from AdventureRV.net)

Easy to replace, new wires and terminals, good to go. (The red wire was the replacement for the fried one.)





It appears the thermostat kits for gas and electric are different, although they are physically the same. One thing for sure, they carry different current. The 12V ones run the circuit board and gas valve, maybe 1 amp or so. The 110V ones run the heater element, around 15 amps. Both the working stats are labelled 60C 15A 125VAC. The overtemp for the electric is different, it has a pop-out reset switch, no temp or load label.

I had forgotten to post this here until today. It appears this problem may be more common than I thought. Jim Roller's Monarch had the same problem, no electric heat. As soon as we uncovered the connections it was obvious they were fried in the same way. We ordered another set of stats and replaced the connections. The photos are actually from Jim's heater. (The input water line fitting had a slight leak, tightened that too.)

If you have a Atwood heater with 110V option, I would recommend inspecting the 110V connections to the thermostats.

My electric heat failed. The heater element failed. It is a wet element so drain the tank and then unscrew it. It is labelled: Camco 02142 1500W 120V. These are widely available around $10. Easy to replace.

Knowing the element rating I was concerned about running the full load through the bimetal switches. They are rated 15A but that is right at their limit. To give them a break I installed a 30 amp contactor relay in the line to the element. (blue wires) The t-stat switches now switch only the relay coil, less than .1 amp. Should last about forever.



Now that I have replaced LP controls, 110 switches and the heating element, that should be the end of this thread!