32
Defrost Operation
The control is equipped with several defrost algorithms
depending on the configuration of the unit (HEAT ONLY,
POWER DEFROST or HEAT/COOL).
On HEAT ONLY models, the control initiates a defrost
cycle when the coil temperature falls to the “Defrost Temp”
setpoint (24°F (-4.4°C) default) established in the Installer/
Service sub-menu. The compressor will shut off, but the
fan will continue to operate to pull warmer air across the
coil in an effort to defrost the coil. When the control sees a
rise in the coil sensor temperature equal to “Defrost Temp”
+ “Defrost Deadband” (10°F (5.5°C) default) or after 15
minutes have passed, the unit will exit the defrost cycle
and will return to normal heating operation based on the
current water temperature and setpoint temperature.
On POWER DEFROST models, the control initiates
a defrost cycle when the coil temperature falls to the
“Defrost Temp” setpoint (35°F (1.6°C) default) established
in the Installer/Service sub-menu. The compressor will
continue to operate (as well as the fan) and a solenoid
valve will open allowing a portion of the hot refrigerant gas
to bypass the heat exchanger and be directed back to the
coil to warm the coil for defrost. When the control see a
rise in the coil temperature equal to the “Def Terminate”
value established in the Installer/Service sub-menu (50°F
(10°C) default), the solenoid valve will shut and the unit will
return to normal heating operation based on the current
water temperature and setpoint temperature.
On HEAT/COOL models, the control initiates a defrost
cycle based on a programmed algorithm involving current
and baseline ambient temperatures, and current and
baseline coil temperatures when the coil temperature
drops below the “Defrost Temp” set in the Installer/Service
sub-menu. Factory default is 35°F (1.6°C). The control
shuts off the fan and activates the reversing valve so the
hot refrigerant gas is directed to the coil to defrost the coil.
When the coil sensor sees temperatures above the “Def
Terminate” value set in the Installer/Service sub-menu,
the unit returns to normal operation based on the current
water temperature and setpoint temperature.
NOTE:
On Power Defrost and Heat/Cool models, the
initial defrost after power ON is a “sacrificial” defrost
where the coil might freeze up more than expected. The
control is learning the parameters of the installation to
establish clear coil temperature conditions for future
defrost operation.
3-Way Valve Control
NOTE:
Pump operation must be enabled through
Service/Installer Sub-Menu to operate 3-way valves
– whether or not the heat pump control will actually
control the pump or not.
The control is equipped to operate system 3-way valves.
The control will set the 3-way valves to the state requested
when there is an active thermostat demand for spa
heat, pool heat or pool cool AND when Pump operation
is enabled through the control. This takes priority over
positions requested by Pump Schedule operations. If the
control also operates the pump, the pump will shut off
for 30 seconds before the valves change state so as to
not have to fight pump head pressure during change of
position. During this change, the display will show “Valve
Chng Delay”.
The 3-way valves are field installed to the #38-40 & #41-
43 terminals on the terminal strip inside the junction box of
the unit. The initialization of the 3-way valves is set in the
Installer/Service sub-menu.
If the water pressure switch (or water flow switch) is
closed when the control needs to change the 3-way valve
position, the control displays “WPS Closed” and waits
indefinitely with the pump and compressor off until the
water pressure switch (water flow switch) opens. After it
senses the open switch, the control switches the 3-way
valves and resumes normal operation.
If no thermostatic demand is requesting operation and
the pump is being run from scheduled pump periods, the
control sets the 3-way valves to the states requested in
the pump period mode schedule.
When there is no demand for pump output because of
manually selected OFF mode, no thermostat demand or
no scheduled pump period, the control leaves the 3-way
valves in their last commanded state. Valve outputs will
not change until there is an active request for them to be
in a different state.
The rating of the control contacts is 0.75A at 24VAC
maximum.
A
WARNING:
If the Spa heating (in a pool/spa system)
is controlled by an external controller, 3-way valves MAY
need to be manually adjusted in order to use the TIMED
SPA feature of this heat pump. Failure to properly adjust
the 3-way valves may result in overheating of the pool
water or other undesirable results.
Battery Back-up
The control is equipped with a battery to maintain control
settings through power outages. This is located on
the upper right rear corner of the control. Replace as
necessary with a BR2032, 3V battery.
High Water Temperature Limit
The control is equipped with a high water temperature limit
which will shut off operation of the compressor if either
water temperature sensor reads at or above 108°F (41°C).
The display will read “Hi Water Temp”. The compressor
will remain locked out until both sensors are below 103°F
(40°C) and the user presses the UP button. The high
temperature limit is active in all modes of operation.
Summary of Contents for Raypak 2450
Page 43: ...43 Figure 15 Piping for Heat Pump Pool Heater and Gas Pool Heater...
Page 52: ...52 NOTES...
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