Toshiba Estia RUA-CP1701H, Service Manual

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Monobloc Outdoor Unit Service Manual
86
9.4.1.13.
Alarm 50 – Exchanger freeze protection on water temp (in cooling)
Alarm 50 Exchanger freeze protection on water temp (in cooling)
This alarm goes off in Cooling or Defrost Mode and when EWT or LWT
is below 4°C.
This alarm is to take in account only if it appears periodically on unit. In
other cases, this alarm informs that the EWT or LWT is too low for
system.
Does water pump normally
operate?
Check the clogging of water filter, if clogged, replace
NO
YES
Is circuit wiring normal?
Repair defective
position
Is the water flow rate too low?
YES
YES
Elimination of blockage element or
change filter
Heating operation
Replace pump
YES
NO
Check the presence of water leakage on circuit
YES
Is there any element which
blocks water heat exchanger?
- Clogging of heat exchanger
- Bypass n heat exchanger
- Clogging of filter drier
Clogging of refrigerant
overcharge / Pipe breakage
/ Abnormal load
NO
Is TR sensor correctly
located?
And are characteristics of TR
sensor good?
YES
Check TR sensor location,
Or change TR sensor
Is water flow rate in
correct range?
YES
Check the clogging of
water filter
YES
Is water pressure drop
in correct range?
Is water flow rate in
correct range?
Is water flow rate in
correct range?
Repair defective position
Replace pump
YES
NO
Fit buffer tank and second pump
Check that the drop losses
of hydraulic circuit are not
too high (piping length….)
NO
NO
NO