Help with hydronic unit heater install in garage

[dave*99]

The story:

I found a Reznor WS44/62 fan forced hydronic unit heater that may work in my son's garage. 500 sq ft garage in Vermont. It's drive out garage under the house and has poured concrete walls mostly below grade. 2 garage doors in good condition.

A new propane fired boiler is being installed for the house and DHW. There will be a dedicated zone and pump available for the garage heater.

The hydronic fan coil has a 2 speed fan. Output is 44,000 or 62,000 BTu.

How do I control this unit? I suspect I need a thermostat connected to the Taco zone control unit. That's easy. How do I control the fan in the unit heater? I was hoping there was a thermostatically controlled switch in the heater that turns on the fan when hot water is flowing. I don't see that in the installation manual.

 

[PoorUB]

What type, (model) Taco zone controller?

If the Taco is a pump zone control, run the thermostat to the Taco, it will run the pump and get hot water to the unit. As far as running the fan you could come off the same thermostat so on a call for heat it closes a relay to run the fan motor.

You could also run a relay off the Taco zone control so when the pump is energized it closes the relay and runs the fan.


I have also seen a thermostat on the water pipe going to the heater. When the pipe warms up, the thermostat will turn on the fan motor. The only short coming, is the fan runs until the pipe cools off. You might be able to put the thermostat on the water coil and it will cool faster when the pump shuts off.

 

[dave*99]

The controller is a Taco SR506-EXP-4

Can I tap the circulator power for the garage zone to power the fan in the unit heater directly? Or is a relay required?

As for the fan running off a thermostat on the pipe, I'm OK with that or the relay approach you mentioned. Are there packaged solutions for this that you prefer?

What are your thoughts on the BTU capacity of the unit I found used for this size garage. (see post #1)

Our goal is really just freeze protection for the house as all the heat and water pipes are in the ceiling above the garage.

 

[4x4Pete]

If you want freeze protection just run the pump for the fan coil 24/7. Cycle the fan on a line voltage thermostat. You will get a bit of heat from the coil running it this way but not as much as you'd think. I have seen quite a few done like this and if the fan doesn't run, the garage keeps around 50°F

 

[dchawk81]

Emotionally, I would say NASCAR. Because the sanctioning body is so oppressive it has to be draining.

 

[PoorUB]

The controller is a Taco ZVC405-4.

Can I tap the circulator power for the garage zone to power the fan in the unit heater directly? Or is a relay required?

As for the fan running off a thermostat on the pipe, I'm OK with that or the relay approach you mentioned. Are there packaged solutions for this that you prefer?

What are your thoughts on the BTU capacity of the unit I found used for this size garage. (see post #1)

Our goal is really just freeze protection for the house as all the heat and water pipes are in the ceiling above the garage.

Ah, a zone valve controller. Do you have a large enough pump on your boiler to get water to the garage?

That zone control will have 24 volt outputs. You could run an 18 guage thermostat wire out to the heater and use a relay to run the fan.

As for a thermostat sensing the water temp at the heater you would have to rig up something.
Personally, I would pull the 18-2 wire and use a relay.

 

[dave*99]

Ah, a zone valve controller. Do you have a large enough pump on your boiler to get water to the garage?

That zone control will have 24 volt outputs. You could run an 18 guage thermostat wire out to the heater and use a relay to run the fan.

As for a thermostat sensing the water temp at the heater you would have to rig up something.
Personally, I would pull the 18-2 wire and use a relay.

I corrected the part number. It’s a SR unit. Can I power the fan in the unit heater from the circulator pump power? Seems ok as fan draws 0.6 amps.

There is a circulator pump for every zone.

 

[PoorUB]

I corrected the part number. It’s a SR unit. Can I power the fan in the unit heater from the circulator pump power? Seems ok as fan draws 0.6 amps.

There is a circulator pump for every zone.

As long as the amp draw is less than the total allowed for the Taco controller you should be able too.

 

[fitter30]

Reznor WS44/62 Suspended Hydronic Unit Heater, 62,000 BTU | First Supply

Reznor WS44/62 Suspended Hydronic Unit Heater, 62,000 BTU

www.firstsupply.com

Installation book page 13 is a wiring diagram. Line voltage thermostat there is no fan control thermostat. Just cycles fan motor.

 

[dave*99]

Reznor WS44/62 Suspended Hydronic Unit Heater, 62,000 BTU | First Supply

Reznor WS44/62 Suspended Hydronic Unit Heater, 62,000 BTU

www.firstsupply.com

Installation book page 13 is a wiring diagram. Line voltage thermostat there is no fan control thermostat. Just cycles fan motor.

Yes I read that - but I don't want a line voltage thermostat on the fan and another thermostat on the circulator pump.

My current plan it to power the fan off the circulator power. The fan draws 0.6 Amps. One WiFi thermostat on the Taco circulator pump controller. If the fan blows cold air initially (a common complaint for this arrangement) I don't care.

I only need freeze protection for all the pipes in the garage ceiling as it is under the house.

 

[fitter30]

Use a relay between t stat and fan motor. Fan motor is a inductive loadunless the t stat is made for it.

 

[dave*99]

Use a relay between t stat and fan motor. Fan motor is a inductive loadunless the t stat is made for it.

Thermostat is a 24V type connected to the Taco SR506 circulator controller. Fan and garage zone circulator pump will both be powered from the 120V output terminals of the Taco controller. The thermostat (24V) will not be connected directly to the 120V fan motor.

 

[Mr onetwo]

The simplest way is to run the pump control with a normal tstat, put 120v power thru a service switch, a speed switch and an aquastat to feed the fan.On a call for heat the pump starts sending heated water to the unit heater.When the aquastat senses heat it will start the fan at your selected speed....eazy peazy. Also, insulate your pipes well. https://www.supplyhouse.com/Resideo...0-DegreeF-range-5-30-DegreeF-Adj-Differential https://www.supplyhouse.com/Fantech-WC15-WC-Series-Variable-Speed-Control-with-On-Off-Switch-5A