Need direction on water heater that does not always light

New gas valve for $80.......

https://www.amazon.com/Atwood-93844-Water-Heater-Valve/dp/B0007XVWWU


Hate to spend $35 for 2 new solenoids only to find 20 yr old gas valve still doesn't pass gas.

It probably will with new solenoids BUT ???

You're call....not mine :B

Old-Buscuit,

I went out in the dark after I read your post. I pulled the red and green wire off the left side of the gas valve. Set meter to x100 and got no response.

put the wires back on. Pulled the red and green off of the right side. The needle went all the way to the right and stopped at 1 OHM.

So I guess I have 2 options. Buy a whole new control valve or replace both coils for $35. What do you think?

Thanks,

Obie

Pull the red wire and black wire off of each gas valve solenoid


(One solenoid at a time so you can install wires back on correctly ----solenoids are 'polarity' sensitive in that you can not cross wires and have it work)


With your analog meter set to X100
Touch red probe to solenoid terminal where red wire connects
Touch black probe to solenoid terminal where black wire connects
This will measure resistance thru coil.....S/B 40-50 ohms

Each solenoid MUST operate for gas valve to open

Circuit Board MUST receive Flame Proof signal to hold DC on solenoids (until t-stat opens)


Gas valve solenoids can be replaced vs replacing gas control valve
Atwood/Hydroflame offers a replacement coil- part number 31000 (replaces old part number 33475) for the White Rogers valve (Which is used by both Suburban and Atwood)

https://pdxrvwholesale.com/products/atwood-hydroflame-furnace-gas-valve-replacement-coil-31000

Test Results

My problem was that the heater worked all summer when I was getting the RV road ready. Went camping and it did not want to light until I tried about 20 times. Brought it home and it worked pretty much every time until this week. Can’t get it to light. So I am following the posted recommendations.

So, been on this for a few hours. Here is what I did and what I found.


1. Tested resistance on ECO. Good
2. Tested resistance on the tstat. Good
3. I then pulled each wire that had a spade, filed, sprayed with electronic cleaner and added dielectric grease.
4. I remove the igniter to work on the ground. It was very rusty. I thought I had the problem. Filed,, sprayed and greased the connections. The ground was now good, but same results
5. Tried to measure OHMs on coil of the gas valve. I have a good analog tester. But I am not good at understanding the different knob settings on the meter. What worked best was to set it on X100. I then put one probe on the ECO spade that had 2 reds that went to the gas control. Other probe to ground At that reading I got about 2 OHMs . So if I read it correctly, this is a problem.
6. So I go to test and same results. A click on and a few seconds later, a click off. No spark.
7. I then try to follow the suggestion from Snowbird. I understand what is going on but I didn’t know where to connect the Positive cable on the water heater. So I say to myself, lets so part of what Snowbird suggested. So I bring a jumper cable from the negative battery post and connect it to a ground on the water heater. I try to fire it up and the same result. Only a click.
8. So I decide to remove the ground from the battery because I was not sure which battery was controlling the heater because none of my fuses say anything about a water heater. So I remove it and everything is dead, so I have the right battery.
9. When I removed the battery, the switch in the RV was in the on position. So when I connected the negative cable to the battery, all of a sudden, I hear the igniter firing. Holy **** Snowbird. But when I go inside, and reset the switch, I only get a click.
10. So I kept trying. Disconnect the ground and connect it back, it fires and sparks but no takeoff. I do it again with a BIC lighter and only a tiny puff of gas lit. The main gas is on because I lit the stove. I loosened the connection at the gas valve and gas was there.
11. I assume something is wrong with the gas valve. But I can not explain why the system fires the igniter when I connect the battery ground but does not fire when I hit the ON switch.
12. I also had my meter on the control vavle side of the ECO and was getting 12volts.



Any thoughts on what I should do?

I think I need a new Control Valve and a new switch

So should I take the control valve apart?

Crabbypatty wrote:
I will service that with those suggestions. Mine takes two cycles to light. It lights off then stops, 3x then red fault light comes on. I turn it off for a minute, then usually by the third automatic try it stays lit. It lights almost every time but just wont stay lit.

Sparks----flame lights....then no flame

That is due to 'flame lit' signal (milliamp generated by flame lighting) is NOT getting back to circuit board via the spark electrode/wire.

Spark electrode:
*Clean with emery cloth to remove any carbon/soot
*Needs to be engulfed in flame when it lights off
*Clean/tighten high tension wire connections
*Assembly mounting screw needs to have clean/tight connection for proper ground
*Ceramic insulator...no cracks

Thank you guys. The contacts need a little attention. I also ordered a new ECO and stat but will test first.i will also run suggested tests. i will report back.

I will service that with those suggestions. Mine takes two cycles to light. It lights off then stops, 3x then red fault light comes on. I turn it off for a minute, then usually by the third automatic try it stays lit. It lights almost every time but just wont stay lit.

Pull high tension wire that goes to spark electrode off of transformer spade.
Check for corrosion....on spade and connector'
Clean both up.....tighten connector and push back on transformer spade

Check that spark assembly mounting screw has clean/tight connection...provides ground source

Check the eco and thermostat units with an ohm meter. They should both be closed for the heater to light. Failures of the ECO are quite common. The eco and stat are purchased as a set for about $12.
Also check the coil of the gas valve, it should be 20 ohms measured from the double red wires at the eco to ground.

I would take a positive and a negative from your battery to your water heater. Feed it through your rig however you can, and connect it to the water heater 12 volt positive and 12 volt negative terminals. If that ends your problem, lift one side and see if it still works. If that doesn't, lift the other side and reconnect the first side lifted.