Skip to main content ↑ ↓
Topic: Rapid Carbon Buildup on Electrodes (Read 986 times) previous topic - next topic

Rapid Carbon Buildup on Electrodes

See photo. The Atwood hot water heater failed to ignite. Carbon was building up quickly on the electrodes for the electronic ignition. So I just cleaned and gapped (1/8 inch) electrodes last week. The propane flame looks normal because there was just a few yellow tips on the flame.

I have since replaced the electrodes and ignition module, so we'll see if this fixes the problem. I am just curious how carbon could build up so quickly on the electrodes.
1997 U270 34FT Build 5140 Cummins 8.3 Allison 3060R
Solar 1920Watts, 14KWH lithium. Orion BMS.

Re: Rapid Carbon Buildup on Electrodes

Reply #1 –
Running rich will cause that. Dirt, debris or insect next in the "U" tube will cause that.

First thing I would do is used compressed air to blow out the "U" shaped burner tube.  Be sure to stand beside the water heater when you do it so you don't get a face full of dirt.

Less likely if all other appliances are working correctly is high propane pressure.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Rapid Carbon Buildup on Electrodes

Reply #2 –
After Brett's suggestion, check the air slider to make sure the screw has not come loose. This can cause a rich mixture. Any yellow other than orange and yellow flashes in the flame means it's generating carbon monoxide and is a rich mixture.

Have you observed the arc from the electrodes when the heater is trying to light?

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Rapid Carbon Buildup on Electrodes

Reply #3 –
Glad I have an Aquahot ;D

just wanted to throw that out there ... Just kidding.. I heard  in the last few days that there is never a problem with the propane heaters.. guess they were not correct.



in its defense I never had an issue with my propane on my trailers and very minimal issues with my aquahot , mostly maintenance and upkeep..

Re: Rapid Carbon Buildup on Electrodes

Reply #4 –
Fixed a lot of propane heaters long ago as a Foretravel manager.  No aqua hots installed in the 80's and early 90's

If it's got parts it will need fixing.  Duh.

"Riding and rejoicing"
Bob & Susan
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Rapid Carbon Buildup on Electrodes

Reply #5 –
Near as I can tell my water heater, and one furnace are 29 years old and still working.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Rapid Carbon Buildup on Electrodes

Reply #6 –
Thanks for the tips.
All screws were and are tight. If the flame shape and tip looks normal; blue with with some occasional small yellowish flashes, this shouldn't foul the electrodes, yes?

I will blow compressed air tomorrow.

BTW, Aquahot is maintenance-free, yes?  ;)
1997 U270 34FT Build 5140 Cummins 8.3 Allison 3060R
Solar 1920Watts, 14KWH lithium. Orion BMS.

Re: Rapid Carbon Buildup on Electrodes

Reply #7 –
The  perfect machine has no moving parts. Quote from "childhoods end" by Arthur Clark
"Riding and rejoicing"
Bob & Susan
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Rapid Carbon Buildup on Electrodes

Reply #8 –
The propane hot water heater has one moving part: the gas solenoid. How many moving parts does Aquahot have? Just curious.
1997 U270 34FT Build 5140 Cummins 8.3 Allison 3060R
Solar 1920Watts, 14KWH lithium. Orion BMS.

Re: Rapid Carbon Buildup on Electrodes

Reply #9 –
Quote from: Tim –
The propane hot water heater has one moving part: the gas solenoid. How many moving parts does Aquahot have? Just curious.
How many moving parts does your coach heating system have? AH is both
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Rapid Carbon Buildup on Electrodes

Reply #10 –
You don't have an AH Tim.  What's your point? When my AH is on 120v heat has one pump, two heat exchanger fans in the LR. That is all we need.  No additional parts to create all the hot water we need too.  And it makes no noise to annoy your neighbors like an LP water heater and LP furnace make.

Be happy with what you have.  I am. Don't complain about what you don't understand and what you don't have.

Re: Rapid Carbon Buildup on Electrodes

Reply #11 –
Word of advise, Whole House Propane Regulators have a life span of 10 years per our dealer.  Soot build up can be from in proper pressure adjustment, or stale propane. If you have gas delivered to your coach ask the delivery guy about having the service guy come out and check your pressures, they usually do it for free.
1988  40' Grand Villa Cat 3208t

Re: Rapid Carbon Buildup on Electrodes

Reply #12 –
Just curious about the AH, does it also exchange heat from the engine while driving?
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Rapid Carbon Buildup on Electrodes

Reply #14 –
Hmmm, the propane tank dial says it is just below 1/4 tank. That should leave about 10 gallons of propane left. Shouldn't that be enough LPG to provide enough pressure? I plan on filling it up next week.

Don't get me wrong, I am a fan of Aquahot, but it is quite complex. It would be nice if I was a full-time RVer.
1997 U270 34FT Build 5140 Cummins 8.3 Allison 3060R
Solar 1920Watts, 14KWH lithium. Orion BMS.

Re: Rapid Carbon Buildup on Electrodes

Reply #15 –
Drive, heat the AH from the engine, heat the coach while on the way.  Hot water when you get somewhere,  no diesel, no electric and still plenty of hot water in the morning.

Re: Rapid Carbon Buildup on Electrodes

Reply #16 –
Quote from: Tim –
Hmmm, the propane tank dial says it is just below 1/4 tank. That should leave about 10 gallons of propane left. Shouldn't that be enough LPG to provide enough pressure?

Yes, as long as there is liquid propane, gas (vapor pressure) is sufficient.  Remember, it is reduced to under ONE PSI by the regulator.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Rapid Carbon Buildup on Electrodes

Reply #17 –
But tank gauges are notoriously inaccurate.
Regards,
Brett

'99 42' Foretravel Xtreme
'14 Brown Motorsports Stacker
'05 Chevy SSR
'02 BMW R1150R

Re: Rapid Carbon Buildup on Electrodes

Reply #18 –
If the stove and furnace work normally, assume propane in the tank is not the problem.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020