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Model SCM Air to Water Heat Pump — Installation, Operation & Maintenance Manual
Section 7: Glycol/Water System (continued)
Glycol/Water System Installation
Obtain all components specied in Figure 11. Make sure all
components and piping comply with applicable local codes.
DO NOT use galvanized pipe anywhere in the system.
Galvanizing will react with the glycol and can cause glycol
degradation and sludge in the system.
• Conrm charge of expansion tank is 12-15 PSIG (with no
water or pressure in the system).
• Install the system piping. DO NOT connect the SpacePak
unit to the system piping until the system has been cleaned
as required below.
The SCM must NOT be connected to the system during this
process.
1. Connect a hose from a fresh water supply to the system ll
hose bib. Note the drain port can be used for this purpose.
The hose bib purge/drain valve should be located low in the
system and close to the SCM return connection.
2. Open the high point purge valve, (not shown in illustration, as
it may be inside the air handler) while slowly lling the system.
Close the valve when air is removed from the system and
water begins to ow out of the valve.
3. Fill the system with fresh water and run water until the system
has been thoroughly ushed clean.
Automatic Fill – When an automatic ll system is installed, the
cooling uid (Glycol/water) must be inspected at least every 3
months, or whenever a leak is detected to ensure the proper
glycol concentration is maintained.
Pressure Test The System
1. Add water to the system as needed to raise the pressure to
25 PSIG (verify that all system components are suitable for
this pressure). Verify that the pressure remains constant for
at least one hour. Locate and correct any leaks.
2. After successfully testing, drain the system and remove the
fresh water hose.
Insulate The Piping
1. After testing and draining the system, apply pipe insulation. Fill
system with glycol/water mixture. Calculate the system volume.
2. See Figure 12, for required glycol concentration for the mini-
mum expected outside temperature.
3. Obtain the required volume inhibited glycol/water solution
premixed or mix in a clean container. (The glycol must contain
an inhibitor to prevent metal corrosion.)
4. Pump the glycol/water solution into the system, allowing air
to escape through the purge valve(s).
5. After lling the system, sample the system uid and verify
glycol and inhibitor percentages, following instructions
provided with the glycol.
The electrical loads given in Figure 1, allow for a pump load of no
more than 5 amps at 110 VAC (2.5 amps at 230 VAC). If the pump
load exceeds this, provide a separate power source to the pump. DO
NOT feed power to the pump from the SpacePak air handler panel.
• Provide a separate power source and overcurrent protection
for the immersion heater. Refer to the Figures 18 and 19 of
this manual for detailed wiring.
SCM Control Wiring Connection
The SpacePak SCM requires a dry contact (relay) signal to
enable and select between heating and cooling modes. They
will not operate on the 24V signals from typical thermostats or air
handlers. Connecting 24V to either of these points will result in
erratic operation and may cause signicant component damage.
• Connect single zone systems to heat pump as shown in
Figure 16.
• Connect multiple zone system to heat pump using SpacePak
SSIC Control Module and instructions included with it.
Refer
to manual supplied with SSIC Control Module for connection
and operational details.
• See Figure 19, for heat pump electrical ladder diagram.
Section 9: Electrical Diagrams.
Low Ambient Temperature Cooling Operation
If cooling operation is desired in a year-round application, or
any time outdoor temperatures are expected to be consistently
below 55˚F, the fan operation should be modied in order to
ensure proper operating conditions within the refrigeration
system. Refer to Section 2, Fig. 3, for instructions.
Note once implemented, this will cause the fans to start and stop
periodically during operation. This is normal behavior during
cooler outdoor temperatures and should not be a concern.
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