Proliphix IMT350c Installation Manual page 6

An Overview about how to Power your IMT350w Internet Managed Thermostat
An Overview about how to Power your IMT350w Internet
Managed Thermostat
Overview
While the thermostat is wireless from the perspective of how it connects to your
network, it is still wired to your HVAC system in the same manner as any standard
24v interfacing thermostat. For a typical heating and cooling system you would have
wires that are used to supply 24v into the thermostat on the RH terminal and then
switch that 24v back out the W1 heat control wire, Y1 for cool, G for fan. (W2 Heat
stage 2 and Y2 Cool stage 2 if you have a dual stage capable system). If you have a
heat pump there would be additional wires for your reversing valve and possible an
auxiliary heat source and lastly an additional compressor control wire if your heat
pump is dual stage capable.
There are two primary methods to power your IMT350w described below.
Using a Common Wire
Historically for many commercial grade thermostats there has been a need to provide
an amount of power that is not practical using standard battery technology. To solve
this problem there is an additional wire that is connected to the HVAC system's 24v
transformer which is known as the "Common". By using a wire that is connected to
the Common terminal on the transformer, you can complete a power circuit and use
the 24v HVAC transformer as the source to power your IMT.
Your current thermostat may or may not have a wire connected as a Common. If it is
available, then you are all set and can use the HVAC Common method to provide
power to your IMT350w thermostat. It is possible to still use this method if you have
either a spare wire in the HVAC wiring bundle that is not currently being used or you
might be able to pull an additional wire from the HVAC system to your thermostat
and use that as the Common.
Any wiring required to add a common wire in your HVAC system should be done
only by a qualified professional. Please consult with your HVAC technician or
Note
your local electrician for further assistance.
If you cannot provide a Common to your thermostat then you will have to look at the
alternative method of powering your thermostat using an HPA (HVAC Power
Adapter).
HPA (HVAC Power Adapter)
The HPA is a device that will take the fan wire (G) from your existing thermostat
wiring and reuse it by making it behave as a Common. What this means that that your
fan will be tied to your Y1 Cooling relay so that when the call for cool starts a single
relay (Y1) would energize the air conditioner compressor and the fan together.
Detailed installation instructions for the HPA can be found in the HPA Installation
Guide.
2 Proliphix Internet Managed Thermostat (IMT) 350c/350w Installation Guide, Release 1.0
Beta Draft Confidential
Part No. 600-03000-350, Rev. 1