27
5680 011 -10
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Minimum cooling override
The return air temperature will be monitored for
unreasonably low values. When the lower limit is reached
the unit will override the thermostat and maintain the
temperature at the set value.
S1
S2
Maximum heating override
S3
S4
Minimum cooling override
Off
Off
90°F (32°C)
Off
Off
65°F (15.5°C)
On
Off
85°F (29.5°C)
On
Off
68°F (20°C)
Off
On
80°F (26.5°C)
Off
On
70°F (21°C)
On
On
75°F (24°C)
On
On
72°F (22°C)
Dip switch settings
The dip switch will allow the selection of custom setup
options. Refer to Variable Table for system options.
Maximum heating override
The return air temperature will be monitored for
unreasonably high values. When the upper limit is reached
the unit will override the thermostat and maintain the
temperature at the set value.
Override Settings
System Select Dip Switch Settings
Four system settings are available. Two for use when the
evaporator is in the supply air stream, two for use when
the evaporator is in the discharge air stream. In each
configuration, the hot water threshold of 85°F or 110°F
(29°C or 43°C) may be selected, this ensures that only
warm air is available during heating operations.
S5
S6
S7
S8
System
OFF
ON
ON
ON
Evaporator in Supply Air / 110°F (43°C)
ON
OFF
OFF
OFF
Evaporator in Return Air / 110°F (43°C)
ON
OFF
OFF
ON
Evaporator in Supply Air / 85°F (29°C)
ON
OFF
ON
OFF
Evaporator in Return Air / 85°F (29°C)
Installation
The adjustments are made on dip switch interface S1 (refer to the wiring diagram on page 58).
The adjustments are made on dip switch interface S1 (refer to the wiring diagram on page 58).
IMPORTANT
Start-up: Do not power the unit until the water supply
has been connected and the system purged of air. The
circulating pump may come on at anytime. Dry operation
of the pump will damage the pump and void warranty.
