Gas Water Heater

[Dennis Alwon]

Does anyone know if it is possible to control a gas water heater with a timer somehow? This water heater has an automatic ignition- no pilot and I see wires in there.

Is it possible to interrupt the ignition wire or would that void UL? I have a client with a gas water heater and she wants to be able to turn it off automatically during the evenings and when they are away.

 

[John120/240]

If no one is home, there should be no need for hot water. So if you cut the gas

supply off with a timer, how do you maintain the tempature in the tank? If you

come home & wish to shower how long would you wait for hot water?

 

[Dennis Alwon]

I may have the answer. You take of the knob and slip this on.

Click Here

 

[Dennis Alwon]

If no one is home, there should be no need for hot water. So if you cut the gas

supply off with a timer, how do you maintain the tempature in the tank? If you

come home & wish to shower how long would you wait for hot water?

I think that is managable with a timer. If you come homwe at 5pm everyday then you set the timer for 4:30 pm. The tank won't be stone cold so less than 1/2 hour to heat it.

 

[Dennis Alwon]

Wow, not much response here. I am thinking a solenoid valve on the gas line may be the way to go. Anyway see an issue with that.

 

[G._S._Ohm]

Wow, not much response here. I am thinking a solenoid valve on the gas line may be the way to go. Anyway see an issue with that.

The one water heater I measured lost 50 w through the insulation so this gives a measure of how much the water temp. will drop.

Post a schematic of the heater; controlling a gas water heater is one thing but controlling it reasonably safely is another.

And there are more problems switching a 28 mV thermostat than a 750 mV one.

 

[roger3829]

Wow, not much response here. I am thinking a solenoid valve on the gas line may be the way to go. Anyway see an issue with that.

Shutting off the gas won't keep the unit from trying to ignite. That may cause a problem. After so many attempts it might lock itself out. Have not tried to do this before.

 

[Dennis Alwon]

The one water heater I measured lost 50 w through the insulation so this gives a measure of how much the water temp. will drop.

Post a schematic of the heater; controlling a gas water heater is one thing but controlling it reasonably safely is another.

And there are more problems switching a 28 mV thermostat than a 750 mV one.

This is why I think a solenoid valve on the gas line would be the best option.

 

[G._S._Ohm]

My WH experiment showed that with no water usage it was 5 hours before the 'stat asked for heat, so a timer set for 5 hours would make no difference at all.

Solving for the likely energy savings for longer timer intervals is a very messy calculation.

If the client does save some $ they are trading this off with a slight risk of danger due to the water heater being fooled into doing something dangerous because the heater is expecting a more or less steady supply of gas.
The danger will vary depending on where you put the modification.

 

[Dennis Alwon]

Shutting off the gas won't keep the unit from trying to ignite. That may cause a problem. After so many attempts it might lock itself out. Have not tried to do this before.

That is a good thought. I really don't want to do this but I told her I would check into it. Sounds like there would be some savings but not significant amounts.

 

[hurk27]

Does anyone know if it is possible to control a gas water heater with a timer somehow? This water heater has an automatic ignition- no pilot and I see wires in there.

Is it possible to interrupt the ignition wire or would that void UL? I have a client with a gas water heater and she wants to be able to turn it off automatically during the evenings and when they are away.

Ok if this WH is pilot-less ignition it has to have a 120 volt supply for the igniter? just put a timer on this supply?

Any other interruption of allowing the water heater to light will result in a sensed error to the control which will shut it down, if the WH has a wired thermostat, it can be interrupted with a dry contact.