Water heater

[Brave Willy]

2004 Brave
Up to 2 days ago the water heater worked fine on gas or ele. Now the electric only comes on when the gas is on at the same time  If I turn the gas off the ele also goes off  I can?t figure out why this is happening

 

[Rene T]

What make and model do you have?

 

[Brave Willy]

I haven?t opened it up yet to check  There are 2 covers that need to be removed to get access  I?ll have to check tomorrow

 

[Gary RV_Wizard]

How did you determine the electric heater element works only when gas is also active?    Once the LP gas burner comes on, the water will get quickly hot anyway, so only a meter on the electric circuit or element is going to tell anything about the heater element.

I'm pretty sure the 2004 Brave uses a 6 gallon Atwood heater with Motoraid feature, but that should be easily verifiable simply by opening the outer access cover in the sidewall.

 

[Brave Willy]

Yes it is an Atwood with motoraid  I know the ele  comes on when the gas is turned on cause I watch my EMS it shows the current draw  If i just turn on the ele no increase when I turn on the gas with the ele switch on there is a 12 amp increase if I turn off the gas the amp draw drops back down

 

[Henry J Fate]

That would be a problem with the control panel or the control board. I am not quite sure how to single out either one but it must be one of the two.

You could temporarily disconnect the electric element while you are using gas and you have 120 volts. The electric won't come on unless you have 120 volts available either shore or generator. I would leave it disconnected unless you are plugged into shore power and just use the gas when unplugged.

 

[Gary RV_Wizard]

If you want to stop it, just turn off the circuit breaker for the heater and the electric cannot come on, regardless of switches. But there is little reason to do that if you have 120v available.

The conumdrum is why it won't come on by itself when the electric switch is on.  Assuming it's the original heater in the coach, the switch is almost sure a 12v trigger for a relay rather than a direct 120v power switch.  It normally activates a relay on the heater, which in turn switches on the 120v power to the element. For some reason that relay won't switch on unless gas mode is also active.  I'm guessing its a 12v power loss problem, i.e. that turning on gas mode also provides the 12v power needed for the 120v relay.  Can't imagine how that would be, but I would start diagnosis at the 120v relay on the heater, verifying that it gets both 120v power (from the source circuit breaker) and 12v power from the heater switch.

 

[Henry J Fate]

If you have an inverter it could possibly power the electric element from the batteries if there is no axillary 120volts available. If that is the case you most certainly want to shut that element down and if you use the breaker, be sure the breaker is dedicated to the element. It should be but never assume.

 

[Brave Willy]

Thanks help  I?ll have to check deeper into my problem when I get home    I?m presently on the road in Texas

 

[Gary RV_Wizard]

If you have an inverter it could possibly power the electric element from the batteries if there is no axillary 120volts available.

That would be a highly non-standard wiring for the heater. No factory install would ever do that (well, should never do that).  If the inverter was an aftermarket install, customer or dealer, then anything is possible and its worth checking out.