HVAC Supply Fan On
or ERV Timer Option Active or Stand Alone Short Pins 31 to 30 and 29 to 28
FALSE
TRUE
Low Temp
Lock Out
FALSE 
Option 51
Lockout
Activated
FALSE 
CO2 Level
Not High
Enough in
Space
FALSE 
Economizer
Full Open
End Switch
FALSE 
Frost Option
Wheel Iced
FALSE 
TRUE
TRUE
TRUE
TRUE
TRUE
ERV Wheel Off
Supply Blower Off
Exhaust Blower Off
ERV Wheel On
Supply Blower Off
Exhaust Blower On
Wheel Maintenance Indicator Off
Supply Blower Maintenance Indicator Off
Exhaust Blower Maintenance Indicator Off
Wheel Maintenance Indicator On
Supply Blower Maintenance Indicator Off
Exhaust Blower Maintenance Indicator On
Frost Option
Wheel Iced
VFD
FALSE 
ERV Power
Exhaust
Mode
FALSE 
Free Cooling
Dry Bulb Enthalpy
Option and W1
and G are Off
FALSE
TRUE | ERV Wheel Modulating |
|
| Wheel Maintenance Indicator On | |
Supply Blower On |
|
| |||
|
| Supply Blower Maintenance Indicator On | |||
|
| Exhaust Blower On |
|
| |
|
|
|
| Exhaust Blower Maintenance Indicator On | |
|
|
|
| ||
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
TRUE | ERV Wheel Stop/Jog |
|
| Wheel Maintenance Indicator On | |
Supply Blower Off |
|
| |||
|
|
|
| Supply Blower Maintenance Indicator Off | |
|
| Exhaust Blower On |
|
| |
|
|
|
| Exhaust Blower Maintenance Indicator On | |
|
|
|
| ||
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
TRUE | ERV Wheel Stop/Jog |
|
| Wheel Maintenance Indicator On | |
Supply Blower On |
|
| |||
|
| Supply Blower Maintenance Indicator On | |||
|
| Exhaust Blower On |
|
| |
|
|
|
| Exhaust Blower Maintenance Indicator On | |
|
|
|
| ||
|
|
|
|
| |
|
|
|
|
|
|
ERV Wheel On
Supply Blower On
Exhaust Blower On
Wheel Maintenance Indicator On
Supply Blower Maintenance Indicator On
Exhaust Blower Maintenance Indicator On
Preheat available if 
pressure or temperature
are correct for usage
Fig. 24 — ERV Sequence of Operation
26
