MITS AIR M-Thermal Quick Manual To Installation And Use

Quick Guide to Installing M-Thermal – Heating and Cooling
With or Without Domestic Hot Water (DHW)
Add-On to Existing Hydronic Heating
1. Introduction
The Mits Air M-Thermal Air to Water Heat Pump is a superior design that can incorporate hydronic
heating, cooling, domestic hot water and solar heating assistance. This pamphlet will deal with
heating only or heating with domestic hot water.
2. Needed before you start:
a. A buffer tank that will have sufficient capacity for the system.
b. If you are adding domestic hot water, you will need a buffer tank that incorporates indirect
domestic hot water heating.
c. A two-stage heating, one stage cooling thermostat.
If you only have two wires going to the existing thermostat and it has only two wires and it will be
difficult to pull new wires, consider using a Tekmar 564 thermostat. While the thermostat is a bit
more expensive, the labour savings will easily off set this additional cost.
d. If you have a cast-iron boiler or black iron piping and are planning to use an ECM pump, it is highly
recommended that you install a magnetic dirt separator to ensure that rust and magnetite does not
cause pump issues.
You will also need two 24vac coil SPST relays and one DPST relay. These are for signal use.
3. Piping:
Before starting, you will need to decide how you will add the M-Thermal to the system. The best way is
to use the buffer tank outlet as the primary loop and the original boiler injecting into the primary loop
through closely spaced T's. If you are unsure of which to use, please call our Hydronics Division at
905-362-5293 or hydronics@mitsair.com and they will be happy to discuss the best strategy for your
particular application.
4. The outlet heat pipe of the indoor unit goes to a 3-Way valve. The cooling outlet is then directly piped to
the air handler.
5. Controls:
You will need a two-stage heat thermostat a 24 vac SPST (Single-Pole Single-Throw) relay and possibly
a transformer. The relay only requires signal contacts. Please review the wiring schematic.
6. Programming the Controller:
The M-Thermal requires the main display to be programmed for your application before it can operate.
At first this looks very confusing, but if you use the fast-programming guide (listed below) this can be
done in minutes.
For suggestions/advice on your design and installation,
contact the Mits Air Hydronics Team:
6125 Netherhart Road, Mississauga, ON, L5T 1G5.
905-362-5293 or hydronics@mitsair.com
Please refer to manufacturer installation manual
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