Table of Contents
Advertisement
Product Description
Features
8
Viessmann AirflowPLUS AH2A Installation, Operating and Service
Condenser freeze protection
If the evaporator coil outlet air temperature is too low or
operating outside of normal conditions, the control will
shut off the outdoor condenser for 5 minutes. Evaporator
coil freezing can cause slugging at the compressor. Dirty
air filters, oversizing of A/C equipment, improper A/C
installation and commissioning and/or poor duct design
may also contribute to evaporator coil freezing.
Pump exercise function
If the internal circulating pump has not run in the previous
24 hours, the control will turn the pump on for 1 minute
to flush the lines and heat exchanger. This will help
ensure that the water lubricated pump does not seize
during long periods of inactivity.
Home freeze protection
The Viessmann AirflowPLUS AH2A series air handlers
have an integrated sensor which will help prevent the
home from freezing due to a faulty thermostat. Should
the ambient temperature get too low, the control will turn
the air handler on automatically and maintain the home
at approximately 40°F (4°C).
Note: this feature will only work if the boiler is turned on
and the air handler has power. While in Home
freeze protect mode the alarm relay and red light
will be on. Refer to page 41.
Status and alarm indicators
A bicolor LED indicator is installed in the air handler
housing and is used to indicate alarm, test mode, and
normal operation. The indicator will display temperature
readings of the sensors during normal operation.
Alarms
Should service problems arise the Viessmann AirflowPLUS
AH2A series will notify the user with an audible alarm
and/or housing mounted LED. Dry contacts are provided
on the controller which can be connected to an external
device such as a warning light or home security system.
Customizing
The heating and cooling features can be field customized
to provide maximum comfort for almost any home or
location. Refer to page 27, 32, 33 and 34.
Advertisement
Table of Contents
