Outside reset?

Andy Morgan_2

Just out of curiosity, why would you reset a water heater?(other than using it for space heating?)


Andy Morgan

R. Morgan Mechanical, LLC

Tom Towne

Outside reset?

Hey guys

Anyone know of a company making an outside reset control for a water heater and if so, how to set it up ? Thanks.

Tom Towne

Andy

I am using the DWH for radiant heating. I end up changing the water temperature all the time because everything is on one thermostat and pump. I would like to to run the system constantly in the winter and modulate the water temperature instead of letting the floor cool off. Although this may not be the ideal set it's what I would like to do for now.

Mark Wolff

Outdoor Reset

Tekmar 260 outdoor resets can be used for water heaters as well as boilers (possibly even the 256, I haven't tried). You will want to wire your water heater power into the boiler power terminals on the tekmar. If the water heater is oil fired, it will be just like a boiler, if it is electric, check the power rating (in amps) for the control, I can't remember off the top of my head, but it should run it just fine. The pumps are only 5 amp max load, but the boiler circuit I believe is more. If you want constant demand, run L1 and L2 to the two terminals for boiler demand. The 120v will tell the tekmar there is a demand. Warm weather shutdown will shut it off whenever you determine. The circ pump wires in normally.

Set your heat source type to low or high mass radiant, whichever you have, and set heat source to low mass boiler for a similar heating curve.

hr

Seems like an

odd blend of high and low tech!

If the water heater is a powered type, it's easy. If not you have to do a "Mark Eatherton" on it. That is install a solonoid in the gas supply to the burner. You need to be able to signal SOMETHING on and off!

Power vented water heaters are more suited to this, but they sure are noisey ****

Expect to assume all liability if you start this type of modification on a WH. I'd do it in my own home, but for a customer??

hot rod

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Steve Eayrs

Do you need to add a solinoid vlv?


OR could you just interupt the call for heat (w/h aquastat), with the tekmar controls heat demand, and let the w/h aquastat run as the high limit???


Not sure why the soliniod would be needed, but I could be missing something.


Steve

hydronicsmike

What about using....

...a Mixing Control instead? Keep the tank warm and pull out of it with an Injection Pump or through a Mixing Valve that could adjust the Supply Water Temperature based on Outdoor Reset? Then you could keep the tank warm enough for whatever else you're using it for and then Mix the Temperature down for your Space Heating Application.

Just another option.

scrook_2

if...

an electric heater it could be 18A to 23A at 240V assuming typical 4500W or even 5500W elements. If the current exceeds resst controller's contact rating you could use the controller to drive a relay with appropriate contact rating.