P23 Water Heat Exchanger Unit Interlock Error (For Only Water Heat Exchanger Unit - Panasonic 2WAY Multi Technical & Service Manual

P23 Water Heat Exchanger Unit Interlock Error (for only water heat exchanger unit)

Error detection method
An error is detected when the following conditions are met:
• After a hot and cold water pump operation command, when the hot and cold water pump interlock signal (no
voltage, a contact) is not ON within 5 minutes.
• When the hot and cold water pump interlock signal turned ON once, but turned OFF again while the hot and
cold water pump operation signal continued.
Troubleshooting
1
Is the hot/cold water pump operation command wiring
Water heat
1-1 connected to the auxiliary hot/cold water pump electrical
exchanger
relay? (Notes 1, 3)
unit's
electrical
1-2 Is a hot/cold water pump interlock connected? (Notes 2, 3)
box
1-3 Are any signal lines severed, faulty or short-circuited?
Is the power to the auxiliary equipment's control board
1-4
switched off?
Is there any chattering in auxiliary equipment's hot/cold water
1-5 pump electrical relay or in the hot/cold water fl ow switch?
(Note 4)
Note 1: Hot/cold water pump operation command TB3: between No. 1 and No. 2 (No voltage a contact output)
Note 2: Hot/cold water pump interlock
Note 3: Operations are possible when there is a short-circuit between No. 3 and No. 4 on the TB3 terminal
board, but this may lead to the coolant freezing or other problems owing to a reduced fl ow volume, so
an interlock must be connected without fail.
Note 4: Switch on the fl ow switch to confi rm that the correct fl ow volume is being maintained in series with the
signals operated by the coolant pump. Check the settings for the fl ow switch.
● See "5. Reference Document" for details on the procedure for replacing the water heat exchanger unit's
control board.
TB4: between No. 1 and No. 2 (No voltage a contact input)
IV–102
Yes 1-2
Request equipment
No
wiring
Yes 1-3
Request equipment
No
wiring
Yes Repair
No 1-4
Yes Switch on the power
No 1-5
Request equipment
Yes
repair
Replace the water heat
No
exchanger unit board