I'm considering fitting a heated floor to my workshop conversion
project. I've pulled permits and am within code to heat any way I like.
This is considered a 'shop conversion'.
I'd like some help with how to wire thermostats, a heater and a pump to
110V. Only electric is available to the detached shop to heat the water
and ideally the heater and pump will be cheap and easy to replace.
Controls would ideally be off the shelf items I can wire up with little
modification.
Here's a diagram of what I think might accomplish this in a simple way.
T - thermostat
P - pump
H - Heater
Tank is just an insulated water storage tank.
The tube of fluid is to supply under floor heating to a concrete
thermal mass, that is to mantain a constant temperature in a room.
Basic logic
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- T1 detects a drop in temp and starts the heating process by turning on H.
- The water begins to heat until T2 reaches the target temp and turns on power to P beginning circulation.
- When the cooler return water fills the tank T2 will fall below target
temp and stop circulation. This ensures cold water is not circulated.
- The cycle continues until T1 reaches it's target temp switching off
the heater. It could optionally turn off the pump as well at this point
to prevent the residual heat in the tank being circulated causing the
room to overheat.
Another possible solution is to use hot tub parts for the heater and
pump. They might be easy to source at little (or no) cost, second hand,
but I think the heater would have to run with the pump, which is OK if
it will work. It would then only require the T1 to detect the room temp
drop and turn on both the heater and pump until the target temp is
reached. The concrete thermal mass will help to regulate the
temperature. This method would still require a tank, just to allow for
expansion. If this is reasonable it should be easier to install and
maintain.
Using a large tank has the advantage that a solar heating panel could
be retrofitted to supplement the system. Colorado is sunny for most of
the winter.
I served a mechanical apprenticeship that involved some electronics and circuit diagrams, but I'm more than a little rusty.
Of course the lower the cost the better. Any input would be appreciated.