Quick Start Manual
18
Installation, Operation & Maintenance  HTV/HTD/HTH SERIES  Heat Controller, Inc.
Warning! The HWG pump Is fully wired from the factory. Use 
extreme caution when working around the microprocessor 
control as it contains line voltage connections that presents 
a shock hazard that can cause severe injury or death!
The heat pump, water piping, pump, and hot water tank should 
be located where the ambient temperature does not fall below 
50°F [10°C]. Keep water piping lengths at a minimum. DO NOT 
use a one way length greater than 50 ft. (one way) [15 m]. See 
Table 7 for recommended piping sizes and maximum lengths.
All installations must be in accordance with local codes. The 
installer is responsible for knowing the local requirements, and 
for performing the installation accordingly. DO NOT connect the 
pump wiring until “Initial Start-Up” section, below. Powering the 
pump before all installation steps are completed may damage the 
pump.
Water Tank Preparation
1.  Turn off power or fuel supply to the hot water tank.
2.  Connect a hose to the drain valve on the water tank.
3.  Shut off the cold water supply to the water tank.
4.  Open the drain valve and open the pressure relief valve or a 
hot water faucet to drain tank.
5.  When using an existing tank, it should be fl ushed with cold 
water after it is drained until the water leaving the drain hose 
is clear and free of sediment.
6.  Close all valves and remove the drain hose.
7.  Install HWG water piping.
HWG Water Piping
1.  Using at least 5/8” [16mm] O.D. copper, route and install the 
water piping and valves as shown in Figures 14 or 15. Install 
an approved anti-scald valve if the 150°F HWG setpoint is or 
will be selected. An appropriate method must be employed 
to purge air from the HWG piping. This may be accomplished 
by fl ushing water through the HWG (as In Figures 14 and 
15) or by Installing an air vent at the high point of the HWG 
piping system.
2.  Insulate all HWG water piping with no less than 3/8” [10mm] 
wall closed cell insulation.
3.  Open both shut off valves and make sure the tank drain valve 
is closed.
Water Tank Refi ll 
1.  Close valve #4. Ensure that the HWG valves (valves #2 and 
#3) are open. Open the cold water supply (valve #1) to fi ll the 
tank through the HWG piping. This will purge air from the 
HWG piping.
2.  Open a hot water faucet to vent air from the system until 
water fl ows from faucet; turn off faucet. Open valve #4.
3. 
Depress the hot water tank pressure relief valve handle to 
ensure that there is no air remaining in the tank.
4.  Inspect all work for leaks.
5. 
Before restoring power or fuel supply to the water heater, 
adjust the temperature setting on the tank thermostat(s) to 
insure maximum utilization of the heat available from the 
refrigeration system and conserve the most energy. On tanks 
with both upper and lower elements and thermostats, the 
lower element should be turned down to 100°F [38°C] or 
the lowest setting; the upper element should be adjusted to 
120-130°F [49-54°C]. Depending upon the specifi c needs 
of the customer, you may want to adjust the upper element 
differently. On tanks with a single thermostat, a preheat tank 
should be used (Fig 15).
6.  Replace access cover(s) and restore power or 
fuel supply.
Initial Start-Up
1.  Make sure all valves in the HWG water circuit are 
fully open.
2.  Turn on the heat pump and allow it to run for 
10-15 minutes.
3.  Set SW12 to the “OFF” position (enabled) to engage the 
HWG.
4.  The HWG pump should not run if the compressor is not 
running.
5.  The temperature difference between the water entering and 
leaving the HWG coil should be approximately 5-10°F [3-
6°C].
6.  Allow the unit to operate for 20 to 30 minutes to insure that it 
is functioning properly.
Hot Water Generator
Table 7: HWG Water Piping Sizes and Length
Unit 
Nominal 
Tonnage
Nominal 
HWG Flow 
(gpm)
1/2" Copper 
(max length*)
3/4" Copper 
(max length*)
1.5 0.6 50 -
2.0 0.8 50 -
2.5 1.0 50 -
3.0 1.2 50 -
3.5 1.4 50 -
4.0 1.6 45 50
5.0 2.0 25 50
6.0 2.4 10 50
*Maximum length is equivalent length (in feet) one way of type L copper.










