Suburban Water Heater Problems

[Blaster 84]

I have a Suburban water heater, Model SW4D, that will not heat on the gas part. I am not even getting and any attempt of the igniter to ignite the gas. I do not smell any gas. Electric heating element works fine. I checked the high temp limit switch with an Ohm Meter and also a jumper wire with no results.
I do have gas as my bottles are full and the range works fine. I have a feeling the problem is the gas valve.
Does anyone have any suggestions for me to try to verify my diagnosis?

[OldCoot]

Check the alignment of the igniter. There are 3 dimensions regarding the position of the wire to the sparker. I think the diagram is on pg 12 of the attached.

[Blaster 84]

Thanks, I'll look at it in the morning.

[Blaster 84]

The electrode gaping is fine. I don't have a microammeter with me so further diagnosis will wait until we return home in a couple months. I can live with just the electrical heating elements until then.

[oldtool2]

Originally Posted by Blaster 84

I have a Suburban water heater, Model SW4D, that will not heat on the gas part. I am not even getting and any attempt of the igniter to ignite the gas. I do not smell any gas. Electric heating element works fine.

You say you do not smell any gas so start with the gas valve. Page 6 and 7 on that pdf. That is a good manual to keep handy.

Jim

[saltyman]

I believe the gas igniter is a product of 12V circuit. Have you checked for a blown fuse? If all is well, you should hear the spark occurring at intervals.

[oldtool2]

Originally Posted by saltyman

I believe the gas igniter is a product of 12V circuit. Have you checked for a blown fuse? If all is well, you should hear the spark occurring at intervals.

It is 12 volts, but would you hear it if the gas valve is off, or not working?

Jim

[OldCoot]

Originally Posted by Blaster 84

The electrode gaping is fine. I don't have a microammeter with me so further diagnosis will wait until we return home in a couple months. I can live with just the electrical heating elements until then.

Make sure the attaching screws are free of rust also. Loosen them and re-tighten them.

[Herk7769]

The gas part of the heater is controlled by the "control board" that routes power from a closed thermostat to the gas valve to make it open and to the igniter to spark the gas.

If you are SURE the thermostat reads "closed" and there is 12 volts available there and there is no gas smell and no sparking noise; there could be a corroded wire connection or the control board needs to be replaced.

[Harkerr]

The light should be on during the ignition cycle. If not check for power to the module. If ok then probably the module. Dinosaur boards are a good replacement.

[Blaster 84]

Done traveling for the and am catching up here. As another test that I tried that I read on a old thread was to try a jumper wire across the high limit switch. When I do that I get a smart which indicate electricity up to that point. Wouldn't that point be beyond the module and the module would be ok?
I have not studied Herks schematic yet.

[Blaster 84]

All the connections are tight, but there might be corrosion underneath then. I will check it when I get back to the RV.

[Harkerr]

Originally Posted by Blaster 84

Done traveling for the and am catching up here. As another test that I tried that I read on a old thread was to try a jumper wire across the high limit switch. When I do that I get a smart which indicate electricity up to that point. Wouldn't that point be beyond the module and the module would be ok?
I have not studied Herks schematic yet.

The module is downstream from the limit switch which should be closed.

[pdqparalegal1]

Mine had a cut off in the gas line at the heater valve. A small inline valve. Just a small screwdriver to open or close it. One time i forgot I had closed it and went crazy trying to diagnose the "no fire" dellima. Sorry, no pictures, that unit gone.

[bop11]

I had a regulator go bad on my propane system and here are some of the symptoms.
The stove would work fine.
The refer would slowly warm up during an 8 hour drive day.
The furnace would ignite and run for a few minutes then the flame would go out, it would then try to relight and you could hear a small explosion then burn for a few seconds then start the process over again.
I don't know about the hot water heater because we always use it on electric.
I hope this helps.

[silverback 35ts]

Originally Posted by Blaster 84

I have a Suburban water heater, Model SW4D, that will not heat on the gas part. I am not even getting and any attempt of the igniter to ignite the gas. I do not smell any gas. Electric heating element works fine. I checked the high temp limit switch with an Ohm Meter and also a jumper wire with no results.
I do have gas as my bottles are full and the range works fine. I have a feeling the problem is the gas valve.
Does anyone have any suggestions for me to try to verify my diagnosis?

Had the same issue last year on my 2010 5er and after I checked I had gas to the valve but none out, so just have the gas valve changed like I did and it will be fine.

[Blaster 84]

Problem solved. I don't know what I did or if I did anything. When I got this morning I accidentally turned on the gas switch instead of the water pump and I heard the gas come on.
Thanks for everyone's input and I'll download the manuals for future reference.
I did find out that WW Grainger also carries these gas valves. But I can't speak to what the price might be compared to an RV supplier.