Water heater lighting and an LP haircut

[chuman70]

I attempted to light my water heater pilot light for the first time tonight and got the pilot to light ok. When I turned the gas on for the burner, flame started coming back out of the burner chamber. (see pics)





I don't think this is supposed to do that. Can anyone tell me what the problem is?

Oh, the LP haircut part..... After watching the flame come out for a while wondering if it was supposed to do that, I leaned in closer and the fire caught some gas from right next to the blue temperature control wheel and singed a little off the top for me. I'm no worse for wear, but I immediately turned the gas off and came here to seek the sage advice of experienced airstreamers. Can anyone tell me what I need to do?
Thanks!!!

[Condoluminum]

As you noted, that is not good...

I'd start by trying to use compressed air or brush to clean out combustion area, and hot air exhaust, which are probably blocked with spider webs or leaves or something...

The burner flame should go up and out the exhaust vents unless there is a physical blockage, kind of like closing the damper in fireplace...

[chuman70]

AHA! Therein lies the problem. I remember the PO telling me he had sealed off the range vent with Duct tape due to a leak. I have not had this trailer long and I forgot to remove that tape and fix the vent seal. Makes sense now that it would need to be vented to allow air flow.
Do the range and the water heater share the same vent?

[Condoluminum]

Range uses vent over the range, with slide lever to open flap of aluminum and start fan whirring away... Some might be just free-swinging flap and fan with rotary switch...

Water heater has integral vent (the area of door with square grille) where hot exhaust air comes right past tank and out the side vent... Would be very odd for PO to seal exhaust or venting for water heater with duct tape, unless he was trying to keep wasps or spiders out.. There is a family of spider types who are attracted to the smell of propane, and can make life miserable if they live in your neighborhood..

BTW, if PO (prior owner...) used duct tape to seal something, the secondary problem like a rain water leak is something you'll have to deal with down the road... Sigh..

[chuman70]

Yes, it was a rain water leak. I meant to fix it as soon as we got home with it, but other more pressing repairs came first and this one was forgotton. What can I use to repair the gasket? Also, how can I check the functionality of the water heater vent?

[Condoluminum]

Rule #1 for addressing exterior water leaks is to avoid use of silicone sealer, whatever color or brand.. Airstream uses Vulkem brand sealant (available at dealers or Vintage Trailer Supply) or Alcoa Aluminum Gutter sealant for smaller and finer leaks...

As for venting of water heater, I'd start with flashlight and lung dusting brush. You might also shoot some compressed air if you have nozzle and air tank... In addition to possible clog in flue, it might also be possible that there is blckage in large aluminum tube that carries propane from regulator/valve to burners.. These usually have slider air vent ports to adjust ratio of propane and air going into burner.. Spiders like to get in there, and slow flow of propane as well.. With strong large flashlight (or worklight) you should be able to see into area where burners are, and then look into exhaust grill to see if there is blockage further up...

[chuman70]

I probably need to blow the gas lines out. It just seems like ther is not enough gas getting to the burner. The flame would stay inside for a little while and then it would gradually creep back out and go up like in the pictures. I tried adjusting the mixture with the slide, but there was no change. I need to try blowing everything out. I let it run for a while being careful not to let the flame burn outside the tube and it seems to be heating just fine.

[Excella CM]

It appears that the flue for the water heater is obstructed.