Water heater won't stay lit in damp weather

[wheelygoode]

We have a 97 LandYacht motorhome with a gas only water heater. We have noticed it is hard to get it going in damp weather, not a real problem as eventually it clears up and we can get it going. Tonight it is pouring rain, and it is expected to be wet for a couple of days. Heating water on the stove works for dishes, not so much for showers!
Is this a common problem, or is there something we should be looking at?
Thank you.

[bkahler]

Wow, interesting problem. I've not heard of this type of problem before.

The only thing that comes to mind is possibly your inlet air duct is partially plugged (mud daubers) reducing the air flow to the sail switch or the moist air is low on oxygen causing poor combustion.

Sorry, probably not much help.

Brad

[Siegmann]

You say "hard to get going". I'm assuming it's not igniting.

My 1998 OEM water heater has a single piece igniter/flame detector (single white ceramic base with two metal probes). It's not too difficult to pull out. You can clean carbon/soot off the tip and check the gap. Also, microscopic fractures in the base can catch moisture and cause it to not spark at the tip. I replaced mine. You might try squirting it with a little solvent to remove moisture. After it evaporates (important!), then try ignition.

[idroba]

There is no 'sail switch' on a water heater.

I expect that your auto ignition circuit board is being affected by the weather, and the spark is not being generated or the location of the electrode is somewhat out of adjustment. Dampness could cause some of the spark current to be reduced just enough so there is not a good spark. The wire to the electrode could also be leaking so the spark is weak when the weather is damp.

Mainly I would check the electrode location vs. the specifications for that water heater to begin with.

[bkahler]

Originally Posted by idroba

There is no 'sail switch' on a water heater.

Duh, for some reason I had furnace on my mind

I was right about one thing...I wasn't much help

[idroba]

Originally Posted by bkahler

Duh, for some reason I had furnace on my mind

I was right about one thing...I wasn't much help

LOL, I have had those days too. I read the question and somehow miss an important part, and the answer I give is not, lets just say, right.

[JCWDCW]

We always had trouble lighting our '89 water heater when it was damp. Has to do with moisture affecting the spark delivery. I used to put a 40 watt light bulb (lit of course) inside the compartment to dry things out when we were testing things in Prep to go south for winter, then it would fire and run just fine. Once it has started the heat of the operation keeps things dry. If you are still having trouble after it has been lit then try some WD40 (or a dielectric spray) on the exposed wires and high tension lead to the spark plug (when the water heater flame is NOT running). Moisture will permit the high voltage to short to ground.
JCW

[wheelygoode]

Thank you to those who replied - drying out the area should work ( light bulb and hair dryer were both excellent suggestions). The coach had been in storage for a month, and first night out it poured rain. It is working now, and regular use should keep the compartment dry (we hope). But the excellent detailed post on what to look for and how to fix is also appreciated.
The forum to the rescue again!
D.

[MelGoddard]

Originally Posted by wheelygoode

We have a 97 LandYacht motorhome with a gas only water heater. We have noticed it is hard to get it going in damp weather, not a real problem as eventually it clears up and we can get it going. Tonight it is pouring rain, and it is expected to be wet for a couple of days. Heating water on the stove works for dishes, not so much for showers!
Is this a common problem, or is there something we should be looking at?
Thank you.

From the 'get-go' my water heater on the 2015 25' FC. would not light in the morning; or light once, then no more. I found that by opening the outside hatch to it, would light every time.
It took three visits to the dealer, 100 KM. AWAY, for them to finally make it work. (still under warranty. Amongst other snags.)
I now have a 2016 30' FC. and I'm hoping that EVERYTHING will work this time.

[JCWDCW]

Quote "It took three visits to the dealer, 100 KM. AWAY, for them to finally make it work. (still under warranty. Amongst other snags.)"

This has been a problem for others also, and as far as I know there has never been a definitive answer to the problem...what was the fix or the reason for the failure to ignite?

JCW

[Kota]

I had a mud robber nest built up around the igniter. Caused it to short when it got damp.

[Mike1997]

Wheelygoode.....Keep in mind that age of the unit is a factor also. I also have a 97 LY diesel pusher that was kept stored inside since new. I bought it in April 2015 with 45k miles on it. Everything original.....my water heater worked fine...in fact to good....at first could not figure out how I always had hot water on trips without turning it on. Discovered it had a heat exchanger and coolant line that keeps it hot while driving. My problem was with the furnace. It had never been used and would not stay on, had to replace computer board and its like new!

Found a few other things that were not working due to age so good luck with your rig. New TV's and sat dish are next on my list

[OTRA15]

Ditto to Siegmann and idroba. You may need a new igniter assembly and/or circuit board, depending on what you have.

In addition to the other drying-out suggestions, these Dampp Chasers might help. They are intended for locations like damp closets, but if you could put a short one in the water heater space safely when you are hooked up to 110 volts, it might dry things out to get the heater going:

http://www.dampp-chaser.com/storage_dehumidifier

I have always used a couple of these in our trailer through our NE winters -- trailer stored outside and winterized -- to keep the mattress and cushions smelling fresh, and to discourage mold. Our family has used them for decades in various older houses without A/C. They work great.

Good luck!

Peter