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OMEGA-VSHYe.F-IOM-2108
12
8.4 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 Bathroom Timer Switch (24VDC)
The ERV bathroom timer switch consists of a push but-
ton and timer option (20,30,40 & 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.
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
to meet design 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.
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 to
14°F (
-
10°C)
the
unit will enter defrost mode. During defrost mode the unit
operates in 40
-
minute cycles modulating between 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
1)
Check that SW1 ON/OFF
Switch is set to ON.
2)
Example shows Hi
-
Speed
set to 3 o
’
clock (82% duty).
3)
Example shows Lo
-
Speed
set to 12 o
’
clock (45% duty).
4)
Check toggle switch SW2 is
in the middle position.