8 | Installation guide
8 | Installation guide
System mode
Refer to Internal Parameter Setting section for
accessing Internal Parameter Menu.
There are 4 system modes:
1. Off mode
• Heat/Cool/Fan outputs are always off
2. Heat mode
• Heat turns On when room temperature is
lower than setting temperature
• 2-pipe system (2P/ 2H)
4-pipe system (4P)
2-pipe – Aquastat version (2A)
• 2-pipe with Auxiliary heat system (2H)
• 2-pipe with Auxiliary heat – Aquastat
version
When call for heat (room temperature below
setting temperature) and remote temperature is
< 85°F/29.5°C
- Hot water valve does not open (W has no
output)
- Auxiliary heat turns on (Y/A has output)
• Auxiliary heat does not turn on (Y/A has
no output) when remote temperature is
higher than or equal to 85°F/29.5°C and
Water Valve opens (W has output)
3. Cool mode
• Cool turns On when room temperature is
higher than setting temperature
4. Auto mode
• Output turns on On/Off according to both
heat setpoint and cool setpoint
• Heat setpoint and Cool setpoint must be
separated by a dead band of 4°F / 2°C
• There is a 4 minutes Heat/Cool switching
minimum off time
• Heat and Cool outputs do not turn On
during Heat/Cool switching minimum off
time
• Heat icon flashes when Heat control; Cool
icon flashes when Cool control
• Heat/Cool control for Auto mode
• 2-pipe system (with and without Auxiliary
heat)
- Remote water temperature sensor must
present for 2-pipe systems
- Heat control when remote temperature >
85°F / 29.5°C
- Cool control when remote temperature <
65°F / 18.5°C
• 4-pipe system
- Control switches to Heat control when
room temperature is lower than Heat
setpoint
- Control switches to Cool control when
room temperature is higher than Cool
setpoint
• 2-pipe / 4-pipe system
• 2-pipe with Auxiliary heat system
Fan speed selection
Fan speed can be directly adjusted at Home screen.
Press [FAN] button to select fan speed: Low/Med/
High/Auto.
If Auto Fan speed is selected:
• If there is no Heat/Cool demand, fan speed
keeps at Low
• Fan output depends on the difference between
room temperature and setting temperature
• In Auto Fan Speed Mode, there is a minimum
4 minutes switching back and forth (delay)
between Fan Speeds
