Gas Water Heater

[smarks911]

We have an '05 Itasca Sun Cruiser with a ten gallon electric/gas water heater. Out last trip the water heater on gas would start up and sound normal but within 1-2 minutes it would start throttling back and come to a complete stop only to restart and go through the same process again. It does this over and over and does eventually make the water hot. I checked the flame and it looks like a nice bluish flame. Don't know what to check next prior to taking to a shop. Anyone had this issue before and know of a fix? thanks.

[GNP99]

Yes, just fixed mine, it is the thermal cutoff. A one shot heat sensing fuse that’s normally closed and sends power to the thermostat. When tripped by excessive heat (190°F), (i.e. blocked burner or flue tube) it cuts power to the circuit board and shuts down ignition. They can be intermittent before they fail, don't want to admit how long it took me to track this one down. Atwood P/N 93866

[shiggs68]

Originally Posted by GNP99

Yes, just fixed mine, it is the thermal cutoff. A one shot heat sensing fuse that’s normally closed and sends power to the thermostat. When tripped by excessive heat (190°F), (i.e. blocked burner or flue tube) it cuts power to the circuit board and shuts down ignition. They can be intermittent before they fail, don't want to admit how long it took me to track this one down. Atwood P/N 93866

The normal thermal protection device is a one-time device. Once activated, it will never reset. They are usually a short piece if solder, once melted, it's done.

The other point is that these are only used on an Atwood water heater, Suburban does not use these. If the OP has Suburban, then no help.

I would question, first what make water heater. And then investigate either the normal thermostat button or the ECO button. Atwood's have one pair controlling both gas and electric. Suburban's have a pair for each heat source.


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[wa8yxm]

Sounds like there might be something blocking the flame/exhaust path. Like an insect nest.

[grtharris]

smarks911, I agree with wa8yxm since it is not locking out.

[doorguy]

We have had this problem in this coach and W. , in subsequent years added more venting to the outside door for fresh air intake. Our water heater is behind a bay door, so I drilled a 2" hole in the water htr cover and placed an aluminum round vent in it to get more air. At times, I will unlatch the bay door and just leave it ajar and the water htr works fine.

[GNP99]

Originally Posted by shiggs68

The normal thermal protection device is a one-time device. Once activated, it will never reset. They are usually a short piece if solder, once melted, it's done.

The other point is that these are only used on an Atwood water heater, Suburban does not use these. If the OP has Suburban, then no help.

I would question, first what make water heater. And then investigate either the normal thermostat button or the ECO button. Atwood's have one pair controlling both gas and electric. Suburban's have a pair for each heat source.


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TravellingRVDoctor, LLC

If every thing in the world was always normal, there would be a lot less frustration. I thought the same thing, that the thermal cutoff was either good or bad. That's one of the reasons it took me so long to fix my WH. It is not a short piece of solder, it is a copper, beryllium or silver pellet encased in a housing, and they definitely can be intermittent. Don't ask me why or how, I didn't design the thing.

Yes he did not state the make of WH, it is an Itasca coach, most likely an Atwood.

On my Atwood, I had already replaced the TSTAT and ECO on the gas side. And also the separate TSTAT and ECO on the electric side for another problem (burned connectors). Still had the exact symptoms as the OP. Removed the WH recently to work on the coach heater motor, and when i reinstalled it, no gas, no ignition. The thermal cutoff had finally completely failed, Replaced the TCO, it's like a new heater.

Noticed one other thing, for troubleshooting, if the RED Pilot Off light is weak and/or barely illuminates when the WH is first switched on, that is indicative of a poor connection or intermittent TCO. Now when the WH is switched on the RED Pilot Off light comes on bright for about a half second before the WH lights.

[charles tuit]

Originally Posted by doorguy

We have had this problem in this coach and W. , in subsequent years added more venting to the outside door for fresh air intake. Our water heater is behind a bay door, so I drilled a 2" hole in the water htr cover and placed an aluminum round vent in it to get more air. At times, I will unlatch the bay door and just leave it ajar and the water htr works fine.

First step before changing parts is to open the door so more oxygen can get to the burner. I also had this problem at high altitude but opening the door solved the problem. If it still does not solve the problem then proceed to the other solutions posted.

[GNP99]

Also before changing parts, this is easy to verify. Temporarily remove the TCO and connect the brown wire directly to the TSTAT You will know in 5 minutes if it is working properly.

[Hikerdogs]

Originally Posted by GNP99

If every thing in the world was always normal, there would be a lot less frustration. I thought the same thing, that the thermal cutoff was either good or bad. That's one of the reasons it took me so long to fix my WH. It is not a short piece of solder, it is a copper, beryllium or silver pellet encased in a housing, and they definitely can be intermittent. Don't ask me why or how, I didn't design the thing.

Yes he did not state the make of WH, it is an Itasca coach, most likely an Atwood.

On my Atwood, I had already replaced the TSTAT and ECO on the gas side. And also the separate TSTAT and ECO on the electric side for another problem (burned connectors). Still had the exact symptoms as the OP. Removed the WH recently to work on the coach heater motor, and when i reinstalled it, no gas, no ignition. The thermal cutoff had finally completely failed, Replaced the TCO, it's like a new heater.

Noticed one other thing, for troubleshooting, if the RED Pilot Off light is weak and/or barely illuminates when the WH is first switched on, that is indicative of a poor connection or intermittent TCO. Now when the WH is switched on the RED Pilot Off light comes on bright for about a half second before the WH lights.

We had a couple similar problems with the ATWOOD water heater in our 2001 Adventurer 32V. Here's a link to the thermal cutoff (fusible link) for the gas side of the water heater. It should be easily visible when opening the access panel.

Atwood 93866 Thermal Cut Off Replacement for Spark Ignition Water Heaters | eBay

As for the venting problem it was for later model years. Winnebago did make a kit to allow more air into the compartment to keep the fusible link from melting. However it didn't apply to this year or model.

Here's a link to the thermostat for the electric side of the heater.

Atwood Water Heater 110V Eco Thermostat 91873 - $17.40

Unfortunately this one is behind a cover on the back side of the heater. About the only way to get to it for replacement (on the 2001 32V model) is to either remove the water pump and squeeze into the compartment or remove the heater from the coach. Even then you'll only be able to use one hand to remove and replace it.

It's a toss up as to which is a better option. Remember there are coolant hoses coming from the engine to heat the water when the engine is running. Unlike the longer coaches there is no access panel to get to the hose connections. To make things more difficult there is sealant around the front flange that's extremely sticky and difficult to remove without damaging either the coach sheet metal or the water heater flange.

I chose to remove the water pump and slide in the cabinet. However since then I've put on a few pounds and I'm not sure I could still fit through the tight opening.