6
REFRIGERANT CHARGING
WARNING:
*SH3QE4M Split System Heat Pumps are shipped
charged with R410A refrigerant and ready
for installation. If repairs make it necessary
for evacuation and charging, it should only
be attempted by qualified trained personnel
thoroughly familiar with this equipment. Under
no circumstances should the owner attempt to
install and/or service this equipment. Failure to
comply with this warning could result in property
damage, personal injury, or death.
The SH3QE4M SERIES of units, when connected to Nortek
approved line-sets and indoor equipment, do not require
the system to be evacuated prior to charging. All of the
components come pre-charged from the factory and the quick
connect couplers allow the system to be properly configured
for use without evacuation afterwards.
After refrigerant line connections and expansion device
installation are completed, it is required that you leak check
the indoor section and all line connections (using proper
methods) before finalizing the full system refrigerant charge.
Note: additional charging instructions located near the end
• Refer to the Quick Reference Data sheet for additional
charging information for this unit with the approved Nortek
indoor units. For reference, these units are listed in the
AHRI Directory with all approved combinations of indoor
coils and units. Installing these outdoor units on systems
that combine it with an indoor coil or unit not listed there, is
not recommended. When approved combinations of indoor
and outdoor units are installed, they should be set up to
operate within the airflow and other operational parameters
prescribed in all of the units provided instructions and
technical specifications.
• Installation of this outdoor unit with other, non-listed
indoor unit combinations may require different airflows,
expansion devices, charge values and system setup from
the instructions provided here and with this unit. Nortek
does not recommend the use of this product in unlisted
combinations, and the system performance and efficiency
values of unlisted unit combinations may be different than
the listed product combinations.
• *SH3QE4M outdoor units with non-AHRI listed indoor coils
are not recommended. Deviations from rated airflows or
non-listed combinations may require modification to the
expansion device and refrigerant charging procedures for
proper and efficient system operation.
• The refrigerant charge can be checked and adjusted through
the service ports provided external to the outdoor unit. Use
only gage line sets which have a “Schrader” depression
device present to actuate the valve.
• An automatic high-pressure switch is factory-installed
installed in these units and is located on the discharge
line after the unit's compressor. This switch is designed to
protect the system when very high pressures occur during
abnormal conditions. Under normal conditions, the switch
is closed. If the system pressure rises to 650 psig, then
the switch will open and de-energize the contactor coil
in the outdoor unit. The switch will close again once the
liquid pressure decreases to 460 psig and allow the unit
to restart.
• An automatic low-pressure switch is factory-installed
on these units and is located on the suction line. This
auto-reset switch is designed to protect the system from
abnormal operation and events that could otherwise harm
the compressor. When the refrigeration system is at normal
pressures, the switch will be closed. If the compressor
suction pressure falls below 20 psig, the switch will open.
If the compressor suction pressure then rises to 35 psig,
the switch will automatically re-close.
• These outdoor heat-pump units have an Anti-short cycle
control incorporated into the defrost control board. This
control will only allow the compressor to restart 5 minutes
after the last call for operation was terminated.
• These outdoor heat-pumps units have been configured
with a compressor crankcase heater (CCH) that will
operate when the compressor is not energized. It is highly
recommended to allow the CCH to operate for 24 hours
prior to the initial unit start-up.
• These outdoor heat-pump units have been configured
with an outdoor thermostat switch in the control panel
compartment for compliance with US 24 CFR § 3280.714
(2022) requirements on Manufactured Housing Applications
with electrical resistance heating means. The SPST switch
will be open when ambient temperatures are above 40F and
will close at 25F. Refer to the Low Voltage Connections
Section for additional information.
• These heat-pump units have an additional Schrader port
on the compressor suction line located on the lower service
panel of the unit, above the refrigerant line connections.
This will allow a qualified technician to make a suction DP
measurement across the system accumulator and reversing
valve, or for the true compressor SH to be measured.
