OMEGA-VSHPe.F-IOM-2205
13
ERV CONTROLS & OPERATION
ERV Control Board
The ERV control board is powered by a 24VDC switch-
ing power supply mounted in the electrical box. DC pow-
er is supplied using the 14
-
pin connector (JP1). This
also powers the modulating actuator and outdoor air
(OA) & bathroom exhaust (BE) ERV fans. Temperature
sensors are connected through the JP2 terminal.
Units features six temperature sensors:
OA –
Outside Air
MA –
Mixed Air (Mix of Outside Air and Discharge Air)
SA –
Supply Air
DA –
Discharge Air
BA –
Bathroom Exhaust Air (Before Core)
EA –
Exhaust Air (After Core)
ERV Timer Switch (24VDC)
The ERV bathroom timer switch consists of a push but-
ton and timer option (10, 20,30 & 60min).
When the timer switch puts the unit on high speed mode
for the set time and the high speed LED (LD2) lights up.
After the timer cycle is expired the unit ERV fans return
to low speed (normal) mode and the low speed LED
(LD4) lights up on the control board. Low speed mode is
default on initial power
-
up.
Airflow Balancing—EA Fan Speed Adjustment
Balancing of the ERV unit between the OA and EA flows
ensure maximum efficiency. The exhaust air fans should
be calibrated on site during start
-
up and commissioning
for both high speed mode (P1) and low speed mode
(P2).
Use the ERV board mounted low (
LO
-
SPD
) and high
speed (
HI
-
SPD
) potentiometers to adjust the fan speed
and static to meet site conditions.
SW2
toggle switch is used for service testing the Lo and
Hi ERV fan speeds without having to set the bathroom
timer. SW2 overrides the bathroom timer input and runs
ERV fan on selected Hi or Lo speed. This must be
placed back in the middle position after testing.
We recommend the following settings as a starting point
for setting ERV fan:
OA Fan Speed Adjustment
During normal operation the OA fan speed is automati-
cally set by the controller potentiometer settings.
Defrost Mode
If the unit measures OA temperatures below
14°F (
-
10°
C)
the unit will enter defrost mode. During defrost mode
the unit operates in 40
-
minute cycles modulating be-
tween fresh air and recycled air.
During fresh air cycles, the S/A control will maintain the
supply air temperature above 50°F.
S/A Control
When the SA temperature drops below 50°F (10°C) the
ERV controller will modulate the OA damper to maintain
SA temperatures above this threshold.
The modulating damper provides maximum fresh air and
avoids the dumping of cold air.
1)
Check that SW1 ON/OFF
Switch is set to ON.
2)
Set Hi
-
Speed to approx. 3
o
’
clock for duty at 80%.
3)
Set Lo
-
Speed to 12 o
’
clock
(45% duty).
4)
Check toggle switch SW2 is
in the middle position.
