Options
13.7 Refrigerant Leak Detection System
If installed, the refrigerant leak detection system is comprised of
two components: the A2L refrigerant sensor and the UPM board.
The sensor continually samples the air and if the concentration of
refrigerant detected is higher than the preset threshold
(15% LFL), it sends a signal to the UPM, which then switches OFF
the compr
essor and turns ON the blower. The compressor
remains OFF until the saturation level is below (15%LFL) and the
power is cycled in order to restore normal operations. If the A2L
sensor is connected to the UPM, it must always remain
connected. If communication is lost, the UPM enters a refrigerant
leak hard lockout fault and energize the alarm contact. To test
that the communication between the sensor and board is active,
the sensor can be disconnected from the UPM, which should
simulate a fault. The A2L sensor for the refrigerant leak detection
system must only be replaced with the part specified on the
spare parts list.
WARNING
When the refrigerant leak detection system is installed, the
unit must be powered except when servicing. Continuous air
circulation is required for the refrigerant leak detection
system to function properly.
13.8 Electric Heat Option
WARNING
Electric Heater Option requires its own electric power supply
separate from the heat pump’s power supply. DO NOT
attempt to wire the package into the same circuit as the heat
pump
Units supplied with internal electric heat require two (2)
separate power supplies. One power supply feeds the
compressor, and a second power supply feeds the electric heat,
fan motor and control circuit. This allows the electric heaters to
continue to operate along with the blower motor in the case of
unit compressor and/or compressor power supply failure.
CF Series model has a number of heater sizes. Refer to Engineer
Submittal
Sheet on the product information page for heater
option compatibility with specific CF series units. (See the QR
code on the back page of the IOM).
13.9 Hot Gas Bypass
The function of the hot gas bypass option is to prevent icing of the
air coil when the unit is operating at low-load conditions. This
situation could arise if the space experiences widely different
heating and cooling loads or a unit sized for heating that has a
much lower cooling load, for example a conference center.
Without a hot gas bypass circuit the evaporating temperature will
fall and
ice could form on the coil restricting air flow and
aggravating the situation. Eventually the coil could be totally
blocked, resulting in possible refrigerant liquid entering the
compressor and failure of the system.
The hot gas bypass valve, located in the compressor discharge
line, di
verts hot gas to the inlet of the air coil. The valve is factory
set to open when the evaporating pressure falls to 105 PSI and
will modulate to prevent the pressure falling any lower. This
setting is field adjustable, and this set point may be adjusted as
required.
Units with the hot gas bypass feature include a limit switch on the
suction l
ine wired in series with the low-pressure switch, which
acts as a safety device. The limit switch shuts OFF the
compressor if it senses the suction temperature is above 120
deg F and triggers a low-pressure fault.
13.10 Pump Relay
The factory installed pump relay option can be used to energize a
supply pump or solenoid valve when there is a call for
compressor operation. This relay can be used to switch either
high or low voltage power.
13.11 DPS Water Flow Proving Switch
The DPS water flow proving switch option prevents compressor
operation if there is inadequate water flow through the water-to-
refrigerant heat exchanger in the heat pump. The DPS operates
by monitoring the water side pressure drop across the water-to-
refrigerant heat exchanger. When the pressure drop between the
water in and water out lines reaches a pre-set value, compressor
operation is enabled.
13.12 Heat Recovery Package (HRP)
The Heat Recovery Package is a factory-installed option on CF
series heat pumps. The HRP can be used to heat potable water
during unit operation using waste heat from the compressor
discharge gas. In some cases, the HRP can provide most or all of
the hot water requirements for a typical home.
The HRP consists of three major components:
• Double-wall, vented refrigerant-to-water heat exchanger
• Circulating pump, and
• Control circuit.
The heat exchanger is rated for use with potable water and is
a
cceptab
le for use as a domestic water heating device in most
building codes.
The pump circulates water between the domestic hot water tank
and HRP h
eat exchanger in the Heat Pump.
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CF Series Heat Pumps — 8733846299 (2024/11)
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