1.800.627.4499
Premium Commercial Controls
ERV
54
TEMPERING CONTROL
Stage 1 turns on a 25% and
Stage 2 at 75% of prop band
Stage 2 turns off at 25% and
Stage 1 at 0% of prop band
Proportional Band
Setpoint -
Proportional Band
Setpoint
STAGE 1
OFF
TEMPERATURE
STAGE 2
OFF
100%
75%
25%
0%
STAGE 1
ON
STAGE 2
ON
Example:
In this case 4°F = 100% which means that 1°F = 25%, which makes our calculation
easy. With the default settings, stage 1 turns on at 75.2 - 1 = 74.2. Stage 2 turns on at 75.2 - 3
= 72.2.
6.4.2.5 Heat Pump 2-Stage Reversing Valve
The reversing valve controls which direction the refrigerant flows. On change of mode
(i.e. cool to heat), there will be a delay before the compressor turns on to allow the valve to
come into position.
Reversing valve settings:
u
Delay: This is the delay between the heating and cooling changeover where the compressor
will not be turned on to allow the valve to get into position.
u
Contact Open: Choose to have the contact open in heat or cool.
6.4.2.4 Heat Pump 2-Stage Auxiliary Heat
The unit allows you to use a 0–10VDC auxiliary heat source when the outdoor temperature is
very cold. It will run a PI control to maintain the heat setpoint with the aux heat instead of the
heat pump. If you have an auxiliary 0–10VDC heat source:
u
Set the
Aux Heat Src?
To YES
u
Set the outdoor temperature at which the unit will change from using the heat pump to
aux heat
u
Adjust the KP and Ti for the PI loop, if necessary.
