Hot Gas Defrost - Jandy JRT Serie Manuel D'installation

Jandy ® JRT Series Heat Pumps
On some installations, the piping from the heat pump
to the pool is very short. The back pressure could be
too low to trigger the pressure switch. If this happens,
it may be necessary to install a directional fitting or
elbows where the return line enters the pool. This will
increase back pressure enough for the heat pump to
operate properly. If this configuration is necessary,
be sure to check that the system flow is above the
minimum requirement of 30 gpm (114 lpm) after the
direction fitting or elbow has been installed.
Make sure the pool filter is clean before making any
pressure switch adjustment: A dirty filter will restrict the
water flow and the pressure switch cannot be adjusted
properly.
To adjust the pressure switch:
1. Be sure that all valves in the system are set to
allow water flow through the heat pump. Start the
filter pump.
2. Set the heat pump control to call for heat. Set the
heat pump control to the POOL HEAT mode.
3. If the heat pump control displays "NO FLOW",
then the flow in the system may be below the
minimum flow of 30 gpm (114 lpm) needed for
the safe operation of the heat pump. Investigate
and correct any flow problems before adjusting the
water pressure switch.
4. The water pressure switch is located on the water
inlet pipe. Remove the blue cover.
5. Re-install the blue cover.
6. After confirming the flow rate is at a minimum
of 30 gpm (114 lpm), slowly rotate the thumb
wheel on the water pressure switch in a
counterclockwise direction until the "NO FLOW"
indicator disappears from the control display.
Remember that there is a time delay before the
heat pump compressor will start.
7. Once the heat pump is running, turn off the filter
pump. The heat pump should turn off immediately.
8. If the heat pump continues to operate when the
filter pump is off, turn the thumb wheel on the
water pressure switch in a clockwise direction
until "NO FLOW" is displayed on the control and
the heat pump shuts down.
9. Check the setting of the water pressure switch by
starting and stopping the filter pump and checking
the control display and operation of the heater
between each flow change.
10. If the water pressure switch cannot be adjusted
to accommodate the conditions listed above,
an external flow switch must be added to the
plumbing system to ensure that the heat pump will
not operate without the proper flow through the
heat exchanger.
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Installation and Operation Manual
ENGLISH
5.7

Hot Gas Defrost

Under certain conditions of temperature and humidity,
frost might form on the surface of the Heat Pump coil.
This layer of frost will interfere with the operation of
the heat pump by making the unit work harder and,
therefore, inefficiently.
The JRT heat pump has a cycle called a defrost cycle,
which removes the frost from the outdoor coil: the unit
will defrost regularly when frost conditions occur.
Two types of Defrost modes are available in the JRT
units:
Hot Gas (set at Factory)
The hot gas defrost process uses the naturally occurring
high-temperature refrigerant vapor from the discharge
side of the compressor to warm the evaporator coil and
melt the ice accumulated on it.
Air Defrost
In the air defrost cycle, the heat pump is automatically
operated in reverse, for a moment, in the cooling cycle.
This action temporarily warms up the outdoor coil and
melts the frost from the coil.
To switch from Hot gas (set as Factory) to Air defrost
mode:
1. Make sure the control is in the OFF mode.
2. To enter the Service Setup mode, press and
hold the MENU, POOL, and SPA buttons for 5
seconds.
3. Press the Up or Down button to display
DEFROST and press MENU to enter the sub-
menu.
4. Use the Up or Down button to scroll through
the Defrost options (HOT GAS and AIR
DEFROST).
Press the MENU button to select the option
5.
desired.
6. Press POOL or SPA to exit the Service Setup
mode.
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