On demand water heater come on when stool is flushed?

[CAT-RN]

2014 Berkshire 390 FL. This is a new coach but for sure not our first coach.

We were hearing a noise in the back of the coach when flushing the stool?? Checking it out I find that each time we flush the stool the "on demand" water heater come on??

So I hold down on the flush peddle for a couple minutes but never seem to got any hot water??

This is the first coach I've had with the on demand system.

Guess it really don't matter as one very seldom would run enough water thru it at any time to even get hot water to it??

Has anyone else noticed this or know why the stool would for any reason be hooked to a hot water line?? Thanks

Russell

[I-RV]

I have a Berkshire for a couple years and have had the Tankless water heater go on upon fishing the toilet. It does not happen too often and I am not sure wether the gas burner goes on, or is it just the fan. It is probably due to a change in pressure in the water lines when the cold water flows for the toilet, somehow the hot line is affected and causes a slight flow which initiates the heater. Another gremlin!
Hank

[CAT-RN]

I'm not sure about the heater either. I'll get the DW down here after bit & check. Mine comes on every time

Russell

[CAT-RN]

I-rv. U are close to right. Here is what mine is doing. Hold the flush peddle as long as u want. Nothing happens. Just as soon as u let off peddle heater fan comes on. ??

So I let up on the peddle real slow. Fan does not come on. Guess it has to do with a sudden back pressure??

Feeling the air out flow on the heater it is not hot. So I guess heater does not fire??

Gremlin it is I guess ? Thanks

Russell

[Mmnsc]

The heater blower will come on if you have any air in the lines. You need to totally purge all the air including the shower, sinks, outside shower, washing machine etc. If you don't have a washing machine and your camper is plumbed for one, air in those lines will cause you to have the symptom you described. When we first got our MH we had the same problem until we finally used the washing machine. According to Girard, air in the lines will always cause the water heater to go on.

[CAT-RN]

Well that can be true?? We have a washer & use it. And now have 2500 miles on coach. Not sure. Maybe it will go away. Air in lines does make since. But should long since be gone?!

Russell

[Phil57]

Mine did that when I first got it for a coupe if months. It hasn't done it since. Very strange and u did nothing to fix it so I would go with Marty and say its air in the lines.


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[CAT-RN]

I think that is probably what it is. But you would think the air be gone by now. I'd say we did 7 or loads in the washer on this trip?? Heck after what I went through on the last POS coach we had. You for sure not hear me complain about this. So far I am well satisfied with the Berkshire!!

Russell

[Campin Cajun]

Originally Posted by Mmnsc

The heater blower will come on if you have any air in the lines. You need to totally purge all the air including the shower, sinks, outside shower, washing machine etc. If you don't have a washing machine and your camper is plumbed for one, air in those lines will cause you to have the symptom you described. When we first got our MH we had the same problem until we finally used the washing machine. According to Girard, air in the lines will always cause the water heater to go on.

This......same thing was happening to me. Now when I first hook up the water I purge all the faucets.

[Mmnsc]

Like campin cajun said on hook up purge all the faucets. I also run water through the hose before connecting it to the coach to minimize any air from getting into the system.


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[Phil57]

Originally Posted by Mmnsc

Like campin cajun said on hook up purge all the faucets. I also run water through the hose before connecting it to the coach to minimize any air from getting into the system.


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You do our do you have Donna do it? Remember we all saw you guys braking camp at Goshen. Sorry that will only be funny if your back is better. Hope it is. That is a good suggestion with the water hose. Someone on the forum suggested that and it works great. Almost no air in the lines.


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[Mmnsc]

Phil
The back only acted ip the day we were breaking camp at Goshen. Was okay the rest of the trip. Spent the first night in Kentucky with only water and electric. Then spent 3 days at Maggie Valley before heading for home.


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[Phil57]

Glad it's better. When is the knee surgery?


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[tmmar]

Phil,
Did you get the private message I sent you?
Tom

[ernest917]

Marty...

Good luck and follow dr orders .... Look to see you down the road a little later....


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[RKC02]

CAT-RN: be sure to use either warm water or do multiple loads using both the hot and cold settings on the washing machine. We had the exact same problem, was advised to purge the air from the lines but no luck until we used both hot/cold lines to the washer. That solved the problem and hopefully will work for you too!


RKC02

[CAT-RN]

Ok. Thanks CO2

Russell

[Phil57]

Don't forget the outside shower.


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[LouNick]

This sounds to me like a check valve before the water heater may help if the issue is reverse flow when the petal is first pushed. Pushing the pedal causes a reduction in system pressure. The pressurized air in the hot water system causes water to be pushed backward through the heater. When the pedal is released, pressure increases and water pushes back through the heater, triggering the flow switch, which starts the combustion air fan, but not long enough to complete the pre combustion purge cycle before the flow stops due to the air being compressed back up to system pressure. The fan then runs through it's post combustion cycle and shuts down.
Installing a check valve before the heater would prevent the backward flow through the heater. That keeps the hot water system fully pressurized and stops the hot water system from needing to be re-pressurized after each flush even if air is trapped in it.


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Lou and Paula

2014 Rockwood 8289WS UltraLite w/Revolution Pinbox Engaged.

2011 F250 Power Stroke Super Duty King Ranch Super Crew Cab w/Reese 16K Hitch

[edgewant]

Ill repeat what a couple of folks have said. It's caused by air in the lines. We were so discouraged with our hw heater, the second one, that while attending a FMCA rally on Perry this past March we stopped by the Girard booth. The rep agreed to meet us at our motorhome to provide a demonstration or training on how to use it. He emphasized several times that the flow sensor really doesn't like any air in the water lines. He instructed us to purge our system by first flushing the toilets, running the shower and faucets and then going outside and running the outside shower. After doing that this season we haven't had any occurrences where the heater runs when it shouldn't. I installed a y with two short hoses, one that goes to the city supply and one that goes to the tank fill. The y has shut offs and I usually flow to the tank when we first setup at a site to remove the air from the supply water line. This helps reduce or eliminate the introduction of air into the system.