Options; Extended Range Option; Unit Mounted Non-Fused Disconnect Switch; Internal 2-Way Water Valve - Bosch QV Series Installation, Operation And Maintenance Manual

QV Series Heat Pumps

OPTIONS

A number of options are available on QV Series of
Heat Pumps. The following details the purpose,
function, and components of each option.

Extended Range Option

QV heat pumps are supplied standard with bi-flow,
balanced port thermal expansion valve tuned to
typical boiler/tower system operating conditions.
For applications that will experience more extreme
fluid flow rates or temperatures (heating fluid
temperatures below 50°F and/or cooling fluid
temperatures below 60°F or above 100°F), an
extended range option is required.
The extended range option on the QV consists of a
bi-flow, balanced port thermal expansion valve and
an insulated water-to-refrigerant heat exchanger.
With the extended range option installed QV units
can provide heating with fluid temperatures as low
as 20°F and as high as 80°F and cooling with fluid
temperatures as low as 50°F and as high as 110°F.
Unit Mounted Non-Fused Disconnect
Switch
QV heat pumps can be supplied with an optional
unit-mounted disconnect switch mounted to the
electrical corner post of the unit. Field electrical
wiring is connected to the switch and the switch
then routes power to the heat pump electrical box.
When the switch is in the "OFF" position, the heat
pump electrical box is completely de-energized.

Internal 2-Way Water Valve

In many applications, including variable pumping
and well water installations, a motorized water
valve is required on the heat pump water circuit.
On the QV series this water valve can be factory
mounted and wired internally to the unit. The QV
series internal water valve option features a 24VAC
motorized water valve rated to 450 psig working
pressure. This valve is wired to open on a
thermostat call for compressor operation (heating
or cooling) and will remain open as long as the
thermostat calls. The valve can remain seated with
up to 20 psi of back pressure on all sizes.
QV Series Heat Pumps
The valve consists of two main parts: the valve
body and the actuator. The valve body is brazed
into the leaving water line of the heat pump and is
a permanent part of the unit. The valve actuator
can be easily removed from the valve body for
service.
Refer to the water side pressure drop table in the
troubleshooting section of this manual to
determine the appropriate pressure drop across
the heat pump with and without the water valve
option.
Note that the 2-Way Water Valve option will
add additional pressure drop between the
water in and water out connections of the
heat pump.
Note that this water valve cannot be used as
an isolation valve.

Economizer

QV series heat pumps can be provided an optional
waterside economizer. The waterside economizer
option allows a cooling demand to be satisfied by
circulating cold water through a water-to-air heat
exchanger (economizer coil) mounted to the
return air opening of the heat pump instead of
energizing the compressor.
The major components of the economizer option
are the water-to-air heat exchanger, the three-way
water diverting valve, the aquastat and the unit
control circuit.
The economizer option operates in the following
sequence:
• When the unit thermostat calls for cooling
operation and the economizer aquastat
indicates that the supply water temperature is
below the aquastat set point, then heat pump
switches from compressor cooling to
economizer cooling mode.
Subject to change without prior notice
Options | 33
8733829041 (2021/07)