Mitsubishi Electric PUHY-P250YJM-A Data Book page 50

(6) Pump interlock circuit
Operating the heat source unit without circulation water inside the water piping can cause a trouble.
Be sure to provide interlocking for the unit operation and water circuit.
Since the terminal block is being provided inside the unit, use it as required.
Wiring diagram
This circuit uses the "Terminal block for pump interlock (TB8)" inside the electrical parts box of the heat source equipment.
This circuit is for interlocking of the heat source equipment operation and the heat source water pump.
Heat source equipment
TB8
1
Operation
ON signal
2
3
Pump interlock
4
Heat source equipment
TB8
1
Operation
ON signal 2
3
Pump interlock
4
Operation ON signal
Terminal No.
TB8-1, 2
Relay contacts output
Output
• When Dip switch 2-7 is OFF
• When DIP switch 2-7 is ON.
Operation
Pump Interlock
Terminal No.
TB8-3, 4
Input Level signal
Operation If the circuit between TB8-3 and TB8-4 is open, compressor operation is prohibited.
Site control panel
TM1
52P
TM2
To next equipment
The relay closes during compressor operation.
The relay closes during reception of cooling or the heating operation signal from the controller.
(Note : It is output even if the thermostat is OFF (when the compressor is stopped).)
TM1 TM2
Rated voltage : L - N : 220 ~ 240V
Rated load : 1A
- 41 -
L N
~ / N 240/230/220V
MCB
X : Relay
Rated voltage : L - N
Rated load : 1A
TM1, 2 : Timer relay
(closes after elapsing
the set time when it is
powered, while opens
promptly when it is not
powered)
52P : Magnetic contactor
for heat source
52P
water pump
MP : Heat source
water pump
MCB : Circuit breaker
*Remove the short circuit
wire between 3 and 4
when wiring to TB8.
MP
: 220 ~ 240V