Manual 2100-635A
Page
12 of 18
BASIC INSTALLATION
(Factory-Installed Versions)
1. Remove blower access door and service door.
Room filter located above air circulation blower.
Install filter.
2. Remove and install air intake hood (see Step 15 of
Basic Field Installation on page 11).
3. Refer to Control Wiring section for suggested
control schemes for the WERVP.
4. After wiring, replace all panels.
CONTROL WIRING
The WERVP comes from the factory with the low
voltage control wires connected to the wall mount
low voltage terminal strip. Care must be taken when
deciding how to control the operation of the ventilator.
When designing the control circuit for the ventilator,
the following requirements must be met.
Control Requirements
1. Indoor blower motor must be run whenever the
WERVP is run.
2. Select the correct motor speed tap in the WERVP.
Using Table 1, determine the motor speed needed
to get the desired amount of ventilation air needed.
For instance, do not use the high speed tap on
a WERVPA5 if only 300 CFM of ventilation air is
needed. Use the low speed tap instead. Using the
high speed tap would serve no useful purpose and
significantly affect the overall efficiency of the air
conditioning system. System operating cost would
also increase.
TABLE 1
Ventilation Air (CFM)
Model
High Speed
(Black)
Medium Speed
(Blue)
Low Speed
(Red)
WERVPA5
WERVPC5
450
375
300
system that in some way can control the system
based on occupancy.
!
IMPORTANT
Operating the WERVP during unoccupied
periods can result in a buildup of moisture
in the structure.
3. Run the WERVP only during periods when the
conditioned space is occupied. Running the
WERVP during unoccupied periods wastes energy,
decreases the expected life of the WERVP and can
result in a large moisture buildup in the structure.
The WERVP removes 60-70% of the moisture in
the incoming air, not 100% of it. Running the
WERVP when the structure is unoccupied allows
moisture to build up in the structure because
there is little or no cooling load. Thus, the air
conditioner is not running enough to remove the
excess moisture being brought in. Use a control
Recommended Control Sequences
Several possible control scenarios are listed below:
1. Use a programmable electronic thermostat with
auxiliary terminal to control the WERVP based
on daily programmed occupance periods. Bard
markets and recommends Bard Part No. 8403-
060 programmable electronic thermostat for air
conditioner and heat pump applications (see Figure
10 on page 14).
2. Use a CO
2
sensor in conjunction with a mechanical
thermostat to keep CO
2
at required levels. Bard
recommends using Bard CO
2
controller 8403-067
(see Figure 11 on page 15).
3. Use a motion sensor in conjunction with a
mechanical thermostat to determine occupancy
in the structure. Bard recommends Bard Model
CS9B*-**** CompleteStat for this application (see
Figure 11 on page 15).
4. Use a DDC control system to control the WERVP
based on a room occupancy schedule to control
the WERVP.
5. Tie the operation of the WERVP into the light
switch. The lights in a room are usually on only
when occupied.
6. Use a manual timer that the occupants turn to
energize the WERVP for a specific number of hours.
7. Use a programmable mechanical timer to energize
the WERVP and indoor blower during occupied
periods of the day.
