Indirect water heater wiring.

ekd4176

I currently have a Burnham AL53A indirect water heater that is leaking and I would like to replace it. I am considering a Burnham AL50SL but as I look at the wiring, the TPI calls for 24v power but I don't know where to get that from. The current setup has a single thermostat wire from the water tank Aquastat that goes to a Honeywell YHR845A switching relay that runs the Taco circulator. The new water heater calls for a Circ/TT hookup as well as the 24v hookup. Should I connect the TPI TT to the YHR845A as it is now and run another line from a nearby 24v transformer to the 24v connection on the TPI. Thanks Eric

Ironman

The electronic aquastat needs 24v to power its logic. Anywhere you can pick up power from will work.

ekd4176

Thank you very much

EdTheHeaterMan

There is no access to the common (C) on the Honeywell YHR845A. You will need to look elsewhere for 24V or go under the printed circuit board to find the C side of the transformer to solder to, but that will void the warranty and the protection of the UL listing of that control.

JohnNY

I really dislike this absurd trend of having to power a controller on something as simple as an indirect water heater.

Nikos10

Hi think i'm have same/similar issue...bought new indirect hot water heater yesterday (last unit was 20 years old).

Connected thermostat to taco sr501 (no wiring change in taco). Taco control makes buzzing sound and zone is always open calling for heat.

Will not start circulator or fire boiler but red light is on and it buzzes like a street light at night. Never did before with old unit.

New thermostat mentions 24v, I see that in the taco box as well but don't know what to do.

I have hot water to heater. I get it by shutting unit kill switch when heater actually needs hot water but once up to temp the zone never shuts off (light) but pump and boiler are off and taco zone buzzes slightly. Can hear when you get close.

Has to be mis wired. I don't understand the 24v but see those markings on the thermostat and taco control. I'm assuming I have to do something there but don't know what.

Looking for advice. Thanks so much...

Zman

What brand heater is that? Do you have the instructions?
It looks like the old wires should be on the other 2 terminals on the left. The terminals on the bottom should be connected to R and C on the Taco to bring power to the controller.

EBEBRATT-Ed

Anything to make it more complicated and more expensive

Solid_Fuel_Man

I think it's done @JohnNY for the flash-bang led display. People get all hopped up if there are cool digital numbers to look at. 

I completly agree with your sentiment. 

JohnNY

Solid_Fuel_Man said:

I think it's done @JohnNY for the flash-bang led display. People get all hopped up if there are cool digital numbers to look at. 

I completly agree with your sentiment. 

Nothing like making things far more complicated than they need to be.

EdTheHeaterMan

@ekd4176 You will need to provide a seperate 24V transformer to provide power to operate the electronic control. This is your diagram


@Nikos10 Yours is easier. This is your wiring diagram.


Three conductor wire from the water heater thermostat to the switching relay. You need a jumper wire to connect the red wire from R on the Taco SR relay on 2 terminals of the water tank thermostat

A third wire (green) for the common or return path to operate the LED and onboard microprocessor of the water heater thermostat.

Merry Christmas
Ed


BTW electric is colorblind... you don't need to use green if your 3 conductor wire has a different color