9
HEAT PUMP WITH FOSSIL FUEL BACK-UP HEAT
(DUAL FUEL SYSTEMS)
Fossil Fuel Switch: The Arzel AirBoss™ Series lets you customize the system for fossil fuel backup
heat, without the need for a fossil fuel kit. When switched to “Fossil Fuel” and the system is operated
in emergency heat mode, the Arzel board will add 50° F to the “HTG. LAT” set-point (up to a safety
maximum of 190° F). *NOTE* Arzel controls must be used as secondary controls only.
The control setting must be below your primary factory protection level.
This accommodates the higher temperatures required for the fossil fuel backup furnace (Fig. 7b).
Fossil Fan Switch: Will break the “G” circuit, allowing the furnace to control the fan cycle when the
system is operated in emergency heat (Fossil Fuel) mode (Fig. 7b).
If you are not using a fossil fuel backup furnace, you must leave these switches in the Off position!
CALL WAITING:
In heating, cooling or automatic priority mode, an opposing call (i.e. a cooling call when in heating mode)
after waiting 20 mins. will be served as follows: The waiting call will shut down the existing service, go
through the Energy Conservation Cycle (ECC) and serve itself for up to 20 minutes. If after this 20 mins.
the earlier call is still there, the service will revert to the original call after completing an Energy
Conservation Cycle. This feature eliminates the problem of opposing service calls waiting too long to be
served.
Rev. 5/12/04
U.S. and Foreign Patents & patents pending.
© copyright 2004 by Arzel Zoning Technology, Inc.
THREE WAY PRIORITY™ SYSTEM
PROVIDES A CHOICE OF HEATING, COOLING OR
AUTOMATIC PRIORITY ( FIG. 8A )
In Heating Priority: Heating priority allows heating to have priority over cooling and cooling to have
priority over constant fan operation. Any zone calling for heating will be served immediately. Any
zone calling for cooling will be served immediately if no other zone wants heating. Any zone can have
constant fan, if no other zone wants either heating or cooling. Heating operation is indicated by red
LEDs (W1 and W2).
In Cooling Priority: Cooling priority allows cooling to have priority over heating and heating to have
priority over constant fan operation. Any zone calling for cooling will be served immediately. Any zone
calling for heating will be served immediately if no other zone wants cooling. Any zone can have
constant fan, if no other zone wants cooling or heating. Compressor operation is indicated by yellow
LEDs (Y1 and Y2).
In Automatic Priority: Auto priority will allow the first call (either heating or cooling) to establish the
priority sequence for this cycle. A heating or cooling call will always override fan-only operation. Any
zone can have constant fan if no other zone wants either heating or cooling.
In Fan ON Operation: Constant fan operation is available unless other zones call for heating or
cooling. Any thermostat in the Fan ON position will start the fan and open its zone dampers for air
circulation. All other zone dampers will be closed automatically. Fan operation is indicated by a green
LED (G).
( Fig. 8a )
