Suburban Water Heater won't light

[Jonesz]

Have done all kinds of searches but am still confused. I have a Suburban SW6DE heater that will not light on propane. It was fine when stored a year ago but now does not work at all other than on shorepower after replacing the electric element which was fried. We have not used the heater on 110 V since buying the unit used 3 years ago. And I am assuming the element has always been toast. So the question I have is: How do I determine whether the problem lies with the control panel or gas valve. I don't want to order a replacement only to find I got the wrong thing. This is what happens: When I turn the heater switch on it tries to light for the 3 programmed attempts and then locks out. There is spark at the igniter but I can detect no propane odour at all. The tube from the valve to the heater seems OK and I did use a small diameter brass wire to poke into the gas oriface. I have recycled the off on switch several times in a row to make sure that the line would be charged with propane. The stove and furnace both light.Lots of propane. I used a mutimeter and checked all four connections to the valve while trying to fire the unit. There is activity at all connectors but I cannot give definite values as the readings fluctuate so widely. Any and all advice appreciated. The nearest dealer is quite a piece away. I phoned them but they do not stock the valve and would have to order one for me. Thanx

[Jonesz]

Thanx for the heads up Forumcoach. Gave it a small tweak and it should be good to go.
Jonesz

[forumcoach]

FYI - Most of the time when I find a bad solenoid on the Suburban Gas Valves it is because the Drip catch under the TP Valve is bent downward away from the Burner. This causes the drips to run right onto the Solenoids and eventually burns them out. Many times it causes intermittent performance as the Solenoid gets wet and quits working until it dries out.

The tray is designed to be bent upward directing the water away from the gas valve. Check yours and see if it needs a bend so you don't burn out your new Solenoid.

[Jonesz]

Update on Water Heater
Got my White Rogers solenoid from PPL, only took a week to Canada from Texas and through customs, good service!
Removed the gas valve from the water heater and you were correct RRR there was no problem in changing the coil. The tamper proof screws I was referring to were above the two regular phillips screws which needed to be removed to access the coils.
Anyway long story short- reinstalled the valve and the water heater fired on the first try!
Just for reference the existing good coil measured 40 Ohms when checking resistance and the new replacement coil for the dud measured 50 ohms when checked out of the package. The bad coil showed no reading. This seems to be the most reliable method of determining if the coil is faulty or not IMHO.
Thanx guys and thanx to this forum it is a GR8 resource
Jonesz

[Jonesz]

Thanx for the info

[RedRollingRoadb]

I had mine off. Never tried with it still on.

[Jonesz]

RRR-Sorry to be a nuisance but one quick? Were you able to replace the coil without taking the valve off the water heater? I haven't started to take it apart yet.
Jonesz

[RedRollingRoadb]

I do not recall any problem.

[Jonesz]

So I did a resistance test on the two coils with my multi meter. The inboard coil ie. closest to the tank is bad. The other coil showed the proper reading approx. 40 Ohms. This is a very simple test and does not require 12V power being fed to the water heater. I have ordered the White Rogers coil from PPL.
RedRollingRoadblock have you got any pointers on installing the new coil when it gets here. Looks to me like the screws are a non-tamper type holding the coils to the gas valve?
Any help appreciated
Jonesz

[Jonesz]

Thanx guys
OB my helping hand is away for a couple of days so I will have to wait to retest the voltage at the coils.
Redrollingroadblock thanx for the link to the WhiteRodgers coil. I may order one from them in any event.
Will post when I get the thing fixed
Jonesz

[RedRollingRoadb]

If after testing you find that it is the solenoid go to the PPL Motorhome parts store and search for 3475. It will bring up a White Rodgers coil that will work. Good luck.

[Old-Biscuit]

Gas Valve Malfunction
With power supplied to ignitor, sparking should occur and the gas valve should open simultaneously.

If sparking occurs but the valve does not open, check the following
a) Place a voltmeter between terminal 4 on the input connector and ground (or across the valve).
Recycle the ignitor by turning the ON/Off switch to "off" for 5 seconds and then back on to determine if voltage is present at the valve.
b)If voltage is present and the valve still does not open, remove wires from valve terminals and retest the valve on a known voltage source.
If valve still does not function, it should be replaced.
c)Check the circuit board connector for good connections.
d)If voltage is not present at terminals 4 and 6 or at the valve, replace the circuit board.

The above info from this service manual......LINK

The gas valve solenoids get power at same time ignitor does....for 6-8 seconds so you will need a helping hand to turn ON/OFF while you test for 12V.

[RedRollingRoadb]

I had one give me the same problem and it turned out to be one of the solenoids. The one closest the tank was known to fail. You can buy the valve with the solenoids for around $125 or just the solenoid for about $25.

I pulled off my valve and took a jumper wires and you could hear and feel the good one kick in. The bad one wouldn't do anything.

I was able to find the solenoid at PPL Motorhome , it is a White Rodgers brand. I don't recall how I figured it out what to get but I got a good tip from Chris Bryant. Maybe he will see this post and chime in.

I don't have time to research it now but will dig around and see if I can find it.

Off to the dentist I go where I know a good time awaits.