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Topic: Am I missing something? [Propane water heater issue] (Read 427 times) previous topic - next topic

Am I missing something? [Propane water heater issue]

We have the 10 gl Atwood Propane/Electric water heater. The propane tank is full.  The Electric element in the heater works great.  The hose that heats the water when the engine is running is also fine.  The propane furnace (both zones) has no issues at all.  The propane stove works good.  However, every time I turn on the propane water heater - it fires up immediately - and then stops after about 1 minute.  The RED fault light inside the coach comes on.  Upon inspection of the water heater- everything looks good.  I decided to replace everything anyway. Atwood 93868 - spark & sensor electrode.  Atwood 96206 - Main burner.  Atwood 91447 - thermal cut-off kit with thermostats and fuses.  Put it all together and fired it up.  Started immediately (as before) and then cut off after about 1 minute.  Basically - no change at all from before the replacements.
Have I missed something?  Or do I have another issue?  Appreciate any help - sure would like to get this fixed.

As a side note - do I even need to think about a Tankless unit?


[Edited topic title to be more descriptive - Michelle]
2002 U295
Build  # 5989
Former:  Alpine Apex (2006 Prototype), Fleetwood Discovery LXE, Berkshire 40 XL

Re: Am I missing something? [Propane water heater issue]

Reply #1 –
Does it have a good strong flame? Maybe the probes are not in the flame correctly and not sending back to the board that there is a flame.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Am I missing something? [Propane water heater issue]

Reply #2 –
Can you post some pictures of the unit? Maybe someone can see something out of place that can be causing this. When it shuts off, do you hear it trying to relight? Do you hear the spark clicking? I found a service manual that has some troubleshooting steps to check
1991 U300 Side Aisle 6V92 Silver #3897
2004 U320 40' #6246

Re: Am I missing something? [Propane water heater issue]

Reply #3 –
My previous U295 would do that after sitting a few months without being used. I think I had air in the lines and wasn't getting good gas to the burner until I cycled the start 3 or more times. Once the lines got good gas flowing it ran without problem. Until the burner had a good flame to heat up the thermocouple, the control circuit would shut off the gas valve.
1999 U270 36, no slide

Re: Am I missing something? [Propane water heater issue]

Reply #4 –
To:  RedTractor -- yes it is a good strong flame and colored (air mixture) as manual recommends.

To:  kggrover  -, no clicking or obvious attempts at auto re-lighting.  I used that manual in my original trouble shooting.  Thank.

To:  Ed&Jo  -  good idea. I will try that.

I originally took a before & after picture to make sure all was back where it belonged.  Changing out these parts was one of my easier RV repair jobs.
2002 U295
Build  # 5989
Former:  Alpine Apex (2006 Prototype), Fleetwood Discovery LXE, Berkshire 40 XL

Re: Am I missing something? [Propane water heater issue]

Reply #5 –
Bob,
Try opening the air inlet all the way open. There is a very small sheet metal screw holding it in position. Make a note of where it is now( for reference if going back to same setting) and then slide it full open and give it a try.
I had the same issue a couple of years ago. It ran fine after I opened it up all the way, but flame seemed a little lean. I adjusted it about halfway from full open and where it was previously and has worked fine ever since.
It'll just take a couple of minutes to do and nothing lost if it doesn't work, you can just put back to the original position.
Mark & Bev
2001 U295 36' Slide
Cummins ISC 8.3 350HP
Build #5802
Jeep Wrangler Toad

Re: Am I missing something? [Propane water heater issue]

Reply #6 –
Bad thermocouple?

The heater's  gas control valve responds to a thermostat that controls the water temperature. When the temp drops below a preset point the igniter sparks, the gas valve opens and fire is invented, a thermocouple is heated by the flame causing it to generate a small electrical current to hold the gas valve open.  If the thermocouple is kuput, or not heated by the flame, the gas valve will close and fire will be un-invented.

Tim Dianics
Pam Sapienza
Vader PupZilla Labrador Canine Beast (AKA Pup)
Columbia, MO
1996 U320 4000
2021 Jeep Gladiator, Diesel

Re: Am I missing something? [Propane water heater issue]

Reply #7 –
Quote from: bobkathy95 –
To:  RedTractor -- yes it is a good strong flame and colored (air mixture) as manual recommends.

To:  kggrover  -, no clicking or obvious attempts at auto re-lighting.  I used that manual in my original trouble shooting.  Thank.

To:  Ed&Jo  -  good idea. I will try that.

I originally took a before & after picture to make sure all was back where it belonged.  Changing out these parts was one of my easier RV repair jobs.
If it's not clicking or trying to relight, It might think it's up to temperature already. Can you check the voltage across the temperature switch? It could be the control box too since you have replaced everything else.
1991 U300 Side Aisle 6V92 Silver #3897
2004 U320 40' #6246

Re: Am I missing something? [Propane water heater issue]

Reply #8 –
Sounds like the control board may be bad. You can take the control board out of one of your propane heaters and try it( it does have a delay in it)like 30 seconds , if it works you have your answer.
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country

Re: Am I missing something? [Propane water heater issue]

Reply #9 –
Quote from: bobkathy95 –
However, every time I turn on the propane water heater - it fires up immediately - and then stops after about 1 minute.  The RED fault light inside the coach comes on.  Appreciate any help - sure would like to get this fixed.

As a side note - do I even need to think about a Tankless unit?


[Edited topic title to be more descriptive - Michelle]
[/quote

Direct Spark Ignition propane burners may have a thermocouple if they're really old, but more likely sense the flame electrically with a probe inserted into the blue part of the flame.  Older units have a separate sense probe, newer units use the spark ignition electrode as the flame sensor, once again the probe must touch the flame to complete the circuit.
1992 Foretravel Grand Villa
U225 SBID Build No. 4134
1986 Rockwood Driftwood
1968 S.I.A.T.A. Spring
1962 Studebaker Lark
1986 Honda VF700C
1983 Honda VF750C
Charlie, the Dog was broken out of jail 24 Oct 2023
N1RPN
AA1OH (H)e who must be obeyed.
 

Re: Am I missing something? [Propane water heater issue]

Reply #10 –
Finally all is fixed.  Turned out it was the control board that was bad.  Atwood had advised to make that the last thing I changed since they rarely go bad.  As a side note:  -  the RV tech who helped me said that the original boards were made by Dinosaur Electronics.  They were very problematic and he was surprised mine lasted 20+ years.  As advised, I got a replacement from Amazon and all is good.  Thanks to all for your help.
2002 U295
Build  # 5989
Former:  Alpine Apex (2006 Prototype), Fleetwood Discovery LXE, Berkshire 40 XL