We have a Montana Legacy. The hot water heater cycles on and off and won't stay on. You can hear the sparking occuring to ignite the propane, it fires, runs for 5 seconds or so, then quites, does this repeatedly. Water pressure is good, full tank of fresh propane. Propane stove top and oven as well as the propane heat all works correctly.
I'm thinking the flow sensor (senses water flow) or the two stage solenoid regulator.
Any assistance would be great. Thanks.
If you leave the hot water running continuous, does the burner stay lit and running? It is the problem with those water heaters that sufficient water flow is needed to make them work. Even a little trickle of water is not enough to keep them heating water.
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Bob & Becky
2012 3402RL
2012 Chevy 2500HD D/A CC 4WD
We have a Montana Legacy. The hot water heater cycles on and off and won't stay on. You can hear the sparking occuring to ignite the propane, it fires, runs for 5 seconds or so, then quites, does this repeatedly. Water pressure is good, full tank of fresh propane. Propane stove top and oven as well as the propane heat all works correctly.
I'm thinking the flow sensor (senses water flow) or the two stage solenoid regulator.
Any assistance would be great. Thanks.
Turn the water heater off, turn on a hot water tap somewhere preferably the shower with highest flow rate. If you're getting good flow of water there, it's not the flow sensor. The residential models have a flow regulator, don't think RV models do. That sensor is used to start the unit; I believe most require around 1 GPM flow rate to start.
If it fires but does not stay lit, that sounds like a flame sensor.
Thanks. I few that the flow is strong. It hadn’t changed overnight. But I thought maybe it just isn’t reading the flow correctly. I’ll consider what you stated. Thank. You
I see an electrode flame probe. It has the ceramic pieces around the igniter rods. But I hear it ticking and then igniting. Just doesn’t stay burning. I also see a probe temperature demand part.
The vacuum switch serves the same purpose as the sail switch in the furnaces; it proves combustion air flow. If it's not working, it would not try to ignite. True, it could be opening during the cycle. These things are notorious for getting condensate inside and failing; normally a total failure, not intermittent.
I'm not familiar with this model, most gas burners will turn the ignitor on and if it doesn't sense flame within a few seconds, it will turn off. If it does sense flame, it will turn the ignitor off, the flame should be self supporting at that point. The ignitor does not stay on during the entire burn. If the time between the ignition and shut down is consistent and repeatable, that to me points to the electrode flame probe.
I’m leaning toward replacing the electrode flame probe. Problem is the water heater is located right along the furnace wall area and the unit needs to come out just to get that access panel off. So I’d really like to do this only 1 time.
It is easier than you think to take the unit out.
Remove the bulkhead wall.
Disconnect the gas line.
Disconnect the water lines.
Unplug the power and control wires.
There is a small angle bracket (maybe 2) screwed into the floor on the back of the unit. Take those off.
I can't remember how many screws hold it in place from the front???
I slid it out onto a TV tray to work on. It is not heavy.
When you first remove the basement wall and expose the rats nest of wires, ducts and pipes - it looks intimidating...see pic below.
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MikenDebbie Aggie ‘77 in the sticks near Austin TX
2019 Chevy 3500 High Country DRW
2018 Montana 3921FB
Aussie Gus + Texas Heeler Jimmy
Update. I looked in the Venturi for a spider or bug obstruction. Saw none. I was able to unsecure it and turn it far enough to get that side panel off. I checked the pressure switch. It held suction and you could hear it clicking on and off. I also took the blue connectors off and turned on the heater. Connected them bypassing the pressure switch. It did the same as it was doing ticking starting, blue flame for 5 seconds or less. The more it tried to fire the less time it stayed on. I took the electrode flame probe out and wire brushed it, same result. I may be looking at a propane pressure issue. Any help is appreciated.
I'm pretty sure that flame sensor is a thermocouple, cleaning won't help it at all if it's faulty.
I understand jumpering out the vacuum switch for troubleshooting; PLEASE never try to run that water heater while the jumper is on. It can cause some very dangerous situations
Update. I looked in the Venturi for a spider or bug obstruction. Saw none. I was able to unsecure it and turn it far enough to get that side panel off. I checked the pressure switch. It held suction and you could hear it clicking on and off. I also took the blue connectors off and turned on the heater. Connected them bypassing the pressure switch. It did the same as it was doing ticking starting, blue flame for 5 seconds or less. The more it tried to fire the less time it stayed on. I took the electrode flame probe out and wire brushed it, same result. I may be looking at a propane pressure issue. Any help is appreciated.
Your rig, being a 2017, is old enough that the propane regulator could be the problem. It's a very easy job to just replace it. That water heater uses a large volume of gas so the regulator must be in good condition to provide plenty of gas to keep it working.
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Bob & Becky
2012 3402RL
2012 Chevy 2500HD D/A CC 4WD
You will have the auto switching regulator on one side and the other will be the high pressure regulator that does not need to be replaced. One of these will work. I used the MEGR-253H which allows higher capacity of propane flow. https://r.search.yahoo.com/_ylt=Awrj...KyfxMEIk9u_0U-
This is likely what the regulator looks like on the opposite side of the rig, and is just there to prevent propane vapor from condensing back into a liquid. https://www.etrailer.com/Propane-Fit...207-30325.html
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Bob & Becky
2012 3402RL
2012 Chevy 2500HD D/A CC 4WD
Linear Mode
