Bosch QV Series Installation, Operation And Maintenance Manual page 34

34 | Options
• In economizer cooling mode the three-way
diverting valve shifts, diverting water through
the economizer coil and then to the condenser
coil. The unit fan operates but the compressor
does not start. This mode effectively cools the
air passing through the heat pump with the
cold water supply instead of compressor
cooling.
• If the call for cooling is satisfied, then the heat
pump fan simply shuts off.
• If, during a call for cooling, the supply water
temperature climbs above the aquastat set
point, then the three-way valve will divert
water back to the condenser coil and the heat
pump compressor will start in the cooling
mode.
Note that the economizer coil incorporates
its own drain pan to collect condensate
from the coil. This pan MUST be
independently trapped and piped into the
drain line for the heat pump.
The QV series economizer option is
designed for free-return applications. If the
heat pump is to be connected to return air
duct work, the economizer may need to be
slightly modified.
The QV series economizer is designed for
cooling only. If heating economizer
operation is desired, consult the factory for
applications and design information.
Note: See page #12, Fig. 10 for Condensate
Drain.
8733829041 (2021/07)
Subject to change without prior notice
QV Series Heat Pumps
QV Series Heat Pumps