Line Voltage Thermostat for Pump Control

[Crazy68Dart]

Towards a KISS design, has anyone used a line voltage thermostat to control their circulation pump for a single zone / garage radiant system? The more common option is a pump controller wired to a low voltage thermostat.

The thermostats have an inductive/motor rating, so in theory it seems that they should work fine. Not sure if it would suffice to allow the circuit breaker to protect any pump short/overload, or if another fuse should be incorporated.

 

[budmur]

As long as the pump is within the thermostat's voltage and current ratings, and the pump has internal thermal protection it should be fine.

 

[Dagny]

Taco makes a circulator that will work with a low voltage thermostat.

 

[Mr onetwo]

Much better to use a pump relay.You want to minimize the amount of line voltage wiring.

 

[nehog]

The pump is an inductive load, line voltage heating is a resistive load. Make sure the thermostat's contacts have rating for the inductive load. (I believe it will...)

Personally I'd use a standard thermostat with a transformer and relay.

 

[Highbeam]

I've seen it done before here and wired mine to work that way. Then use a water heater/boiler that has it's own thermostat to maintain water temperature. Some of the boilers seem to also have a control for the pump built in so you trigger the boiler with a low voltage stat and then the boiler turns on the system.

 

[sierradmax]

I love the taco zone control relays. Easy way to interface low voltage t-stats, boiler & circulator control.

 

[jlckmj]

I use exactly that, a line voltage thermostat wired directly into the pump.
It has worked perfectly for years.

Jim

 

[Crazy68Dart]

I use exactly that, a line voltage thermostat wired directly into the pump.
It has worked perfectly for years.

Jim

What is your setup? Boiler, conventional or on-demand water heater? How far away is the thermostat from your mechanical (water heater, plumbing, pump, etc?)