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Options
13 Options
A number of options are available on CL Series of Heat Pumps.
The following details the purpose, function, and components of
each option.
13.1 Unit Mounted Non-Fused Disconnect Switch
CL 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.
13.2 Internal Two-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 CL series this water valve can be
factory mounted and wired internally to the unit. The CL series
internal water valve option features a 24VAC motorized water
valve rated to 300 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.
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 Two-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.
36 |
13.3 Economizer
CL 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
Option Card, and the unit control circuit.
The economizer option operates in the following sequence:
Validates that Operating Mode Dip Switch SW1 (
Fig. 23) position "2" is in the "ON" position.
The heat pump switches from compressor cooling to
economizer cooling mode when the unit thermostat calls for
cooling operation and the water in temperature thermistor
indicates that the supply water temperature is below the
desired set point specified in:
—
Units with Option Card: The Cool Set Point
Potentiometer (
Refer to Fig. 23).
—
Units with DDC: The Bosch Equipment touch or
building management.
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 set point specified in the option card or
DDC (as indicated above), then the three-way valve diverts
water back to the condenser coil and the heat pump
compressor will start in 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 CL 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.
CL Series Heat Pumps — 8733838716 (2024/05)
Refer to
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Table of Contents
Troubleshooting
