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Premium Commercial Controls
ERV
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
Se
Proportional Band
Setpoint
STAGE 1
OFF
TEMPERATURE
STAGE 2
OFF
0%
25%
75%
100%
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 66.2 + 1 = 63.2. Stage 2 turns on at 66.2 +
3 = 65.2.
6.4.2.3 Heat Pump 2-Stage Heating Operation
This type of cooling cycles two stages of heating to maintain the heating setpoint. You must
set a prop band value. This value represents 100%; the wider the prop band the slower the
response. Then you specify the “on point” for stages one and two in percentages. Stage one
will turn off at setpoint and stage two will turn off at the on point for stage one. There is also a
minimum on and off time to prevent over-cycling.
If in heating mode, and the unit calls for heating, it puts the tempering mode output used for a
reversing valve, in the heat position and after a delay, will turn the compressors on and off to
maintain the heating setpoint.
