Piping; Flow Regulation - Bosch QV Series Installation, Operation And Maintenance Manual

QV Series Heat Pumps

PIPING

Supply and return piping must be as large as the
unit connections on the heat pump (larger on long
runs).
In order to avoid possible vibration, use flexible
hose between the unit and the rigid system.
NOTICE: Never use flexible hoses of a
smaller inside diameter than that of the
water connections on the unit.
Units are equipped with female pipe thread fittings
for water connections.
NOTICE: Piping systems that contains steel
pipes or fittings may be subject to galvanic
corrosion. Dielectric fittings should be used
to isolate the steel parts of the system to
avoid galvanic corrosion.
To prevent leaks and possible heat exchanger
fouling, use Teflon tape sealer when connecting
water piping connections to the unit.
NOTICE: Do not overtighten the
connections.
Install ball valves in the supply and return lines for
unit isolation and unit water flow balancing.
QV units are supplied with a copper or optional
cupro-nickel condenser. Copper is adequate only
for ground water that is not high in mineral
content. Refer to Table 5.
NOTICE: Proper testing is required to
ensure the well water quality is suitable for
use with water source equipment.
In conditions anticipating moderate scale
formation or in brackish water, a cupro-nickel heat
exchanger is recommended. (Refer to the water
quality table on page #24.) Water quality must
meet the standards stated in the table.
Both the supply and discharge water lines will
sweat if subjected to low water temperature.
Insulate lines to prevent damage from
condensation.
QV Series Heat Pumps
All manual flow valves used in the system must be
ball valves. Globe and gate valves must not be used
due to high-pressure drops and poor throttling
characteristics.
Pressure/temperature ports are recommended in
both the supply and return lines for system flow
balancing and determining the system capacity
versus rated conditions. The water flow can be
accurately set by measuring the water-to-
refrigerant heat exchangers water-side pressure
drop. See the unit specification sheets for the
water flow and pressure drop information.
NOTICE: Do not expose water piping to
freezing ambient temperatures.
NOTICE: Never exceed the recommended
water flow rates as serious damage or
erosion of the water-to-refrigerant heat
exchanger could occur.
Always check carefully for water leaks and repair
appropriately.

Flow Regulation

Flow regulation can be accomplished by two
methods. Most water control valves have a flow
adjustment built into the valve. By measuring the
pressure drop through the unit heat exchanger, the
flow rate can be determined. Adjust the water
control valve until the desired flow is achieved.
Since the pressure constantly varies, two pressure
gauges may be needed in some applications.
An alternative method is to install a flow-control
device. These devices are typically an orifice of
plastic material designed to allow a specified flow
rate that are mounted on the outlet of the water
control valve. Occasionally these valves produce a
flow noise that can be reduced by applying some
back pressure. To accomplish this, slightly close
the leaving isolation valve of the well water setup.
Subject to change without prior notice
Piping | 13
8733829041 (2021/07)