Mechanical Timers Installation 99-101
The Mechanical Timer is a 2 wire “dry
contact” timer. A jumper wire must
be connected between 2 (ON) and
3 (RED). Connect the 2 timer wires
to ON and HI.
Timers mount in standard electrical boxes
Use 3 wire 20 gauge (min.) 100 ft length (max.) low voltage wire and multiple timers individually wired back to the unit.
Caution:
Consideration should be given to competing airflows when connecting the HRV in conjunction with an air handler/
furnace blower system.
Building codes in some areas require “fully-off” functionality. Check with your local building authority before
modifying the unit to “standby-off”. Unintentional operation of the HRV by the end user may occur if the unit is
modified from “fully-off” to “standby-off”.
Attention/Caution
2 wire timers require a
jumper wire between
ON and RED on the
terminal
block
Connect the 2
wires from the
timer to ON and HI on the terminal block
.
Interlocking the HRV to an Air Handler or Furnace Blower
Connecting the HRV as illustrated will ensure the air
handler/furnace blower motor is operating whenever
the HRV is venting.
The HRV must be interlocked to the furnace/air handler
with a simplified installation (return/return installation)
and should be interlocked with a partially dedicated
installation.
HRV Terminal Block
Wire
Connector
Furnace
Terminal Strip
Furnace
Thermostat
Setting “Standby” When Using a Main Control
The HRV will be “fully-off” when the off position is selected on the main control. Timers and/or oth-
er controls will not function when the HRV is in the off position.
The “fully-off” feature can be modified to “standby-off” by adding a jumper on the terminal block
between 2 (ON) and 3 (RED). “Standby” can also be achieved by setting the main control to the ON
position and selecting speed 0*. Timers and/or additional controls will initiate high speed ventilation
when activated.
*Speed 0 is not available on all controls.
Operating the HRV Without a Main Control and Adding Dry Contact Controls
A jumper must be in place between 2 (ON) and 3 (RED) on the terminal block to activate the HRV for
timers and/or dry contact controls.
Adding Dry Contact Controls
Low Speed: A jumper between 2 (ON) and 1 (LOW) initiates low speed ventilation.
High Speed: A jumper between 2 (ON) and 6 (HI) initiates high speed ventilation.
Dehumidistat: A dry contact for a dehumidistat is connected between 2 (ON) and 10 (BLK)
The HRV must have a jumper in place between 2 (ON) and 3 (RED) on the terminal block when
installing the unit without a main control.
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