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(8) Pump interlock
The unit may be damaged if it is operated with no water circulating through the pipes.
Be sure to interlock unit operation and the water-circuit pump. Use the terminal blocks for interlocking TB142A (IN1) on
the unit.
IN1
TB142A
Water Pump
Strainer
Control Box
In broken lines are field
supply products.
Operation signal
Pump interlock
Pump operation
Example drawing for pump interlock
(9) Anti freeze mode (Dip SW4-4 ON)
Anti freeze mode is to prevent water pipe from freezing.
The Anti freeze mode can set the heating temperature range between 10ºC~45ºC enabling the unit to maintain low water
temperature to prevent water pipes from freezing.
[Fig. IV. 3. (8).1]
TB141A
TB142A
OUT1
IN1
TM1
52P
MCB
䌾
220/230/240V
52P
MP
Control Box (field supply)
L
N
Unit
TM1
Relay
Timer relay (closes after elapsing the
set time when it is powerd, while opens
promptly when it is not powerd.)
Magnetic contactor for water pump
Water pump
Circuit breaker
X :
TM1 :
52P :
MP :
MCB :
*Remove the short circuit wire of IN1 when wiring to
TB142A.
*Decide TM1 time lag considering circuit water volume
and pump specifi cation so that the PWFY unit start its
operation when the water is fully circulated.
Operation ON signal
Terminal No.
TB141A OUT1
Relay contacts output Rated voltage : L-N : 220
㨪
240V
When Dip switch 3-6 is OFF
The relay closes during reception of cooling or heating operation signal from the remote controller.
(Note : it is output even if the thermostat is OFF.)
When Dip switch 3-6 is ON
The relay closes during thermo-ON.
Rated load : 0.6A
Output
Operation
Pump interlock
Terminal No.
Input
Operation
TB142A IN1
Level signal
If the circuit of TB142A IN1 is open, compressor operation is prohibited.
Use of PWFY unit with the water pump can cause a heat exchanger freeze depending on the ambient air temperature or the
operation status of other indoor units in the same refrigerant system. This problem has become preventable by connecting the
water pump to the external output (TB141A : OUT1) contact so that when thermistors detect low water temperature, the water
pump is actuated to prevent heat exchanger from freezing.
The freeze prevention control is not associated with DipSW3-6.
Set DipSW1-10 to ON to invalidate the control for cases where there is no risk of freeze.
[Fig. IV. 3. (8).2]
[Fig. IV. 3. (8).3]