Proliphix IMT Installation Manual page 19

Installing and Wiring the Thermostat
When controlling these non-HVAC system devices, an external relay is used to
provide a 24v interface to the IMT550 and, on the other side of the external relay, the
line voltage load is switched.
The following are the two methods used to provide power to the 24v side of the
external relay circuit:
Use an external power source with a transformer supplied by the installer
Use the existing HVAC 24v transformer
Using the HVAC transformer is not normally recommended. Doing so may put too
much of an electrical load on the HVAC transformer, which can cause a failure of
Caution
the HVAC system. Please check with your qualified professional installer to ensure
the HVAC transformer is not overloaded.
Basic Wiring Connections and Jumper Settings
The following describes basic wiring connections and jumper settings using the two
available Auxiliary Relays that are on the IMT550c/w.
Auxiliary Relay Setup Using an External 24VAC Source
Figure 7
auxiliary relay when the external device (power source) is supplying the IMT550
auxiliary inputs with a 24VAC source. One conductor from the external relay is
connected to Normally Open (NO) or Normally Closed (NC) and one wire from the
external power transformer is connected to the COM terminal on the aux relay
terminal block. The red line in the diagram represents the circuit path as it flows
between the external relay and the auxiliary relay on the IMT550.
12
Beta Draft Confidential
is a circuit diagram showing the circuit path (red line) and how to wire the
Proliphix Internet Managed Thermostat (IMT) Installation Guide
Part No. 600-03100-000, Rev. 4