Mitsubishi Electric City Multi CMB-WP108V-G, Service Manual

Page: 209 / 301

[
IX
Troubleshooting ]
- 200 - HWE1113B GB
Cause Check method and remedy
4. Long piping length
The cooling capacity varies greatly depending on the
pressure loss. (When the pressure loss is large, the
cooling capacity drops.) Check the piping length to determine if it is contrib-
uting to performance loss.
Piping pressure loss can be estimated from the
temperature difference between the indoor unit
heat exchanger outlet temperature and the satura-
tion temperature (Te) of 63LS. ->Correct the piping.
5. Piping size is not proper (thin)
6. Insufficient refrigerant amount
Protection works and compressor frequency does
not rise due to high discharge temperature. Refer to 1-1. (Compressor frequency does not rise
sufficiently.)(page 199)
Refer to the page on refrigerant amount
adjustment(page 121)
7. Clogging by foreign object Check the temperature difference between in front
of and behind the place where the foreign object is
clogging the pipe (upstream side and downstream
side). When the temperature drops significantly, the
foreign object may clog the pipe.
-> Remove the foreign object inside the pipe.
8. The indoor unit inlet temperature is excessively.
(Less than 15°C [59°F] WB) Check the inlet air temperature and for short cy-
cling. Change the environment where the indoor
unit is used.
9. Compressor failure
The amount of circulating refrigerant decreases due
to refrigerant leak in the compressor. Check the discharge temperature to determine if
the refrigerant leaks, as it rises if there is a leak.
10. HBC controller LEV3 actuation failure
Sufficient cold water is not supplied as sufficient sub
cool cannot be secured on the HBC controller due to
LEVI, 2, and 3 actuation failure. Refer to the page of LEV troubleshooting
( [4] -5- ).(page 212)
11. TH12, TH15 and 63HS1 sensor failure or faulty wir-
ing
LEV3 is not controlled normally.
Œ
Check the thermistor.
Œ
Check wiring.
12. HBC controller 3-way valve/water flow rate control
valve actuation failure
Sufficient cold water is not supplied because of the
insufficient water flow rate and coexistence of cold
and hot water on the HBC controller due to 3-way
valve/water flow rate control valve actuation failure.
Œ
Refer to the section on 3-way valve/Water flow
rate control valve fault under
"Troubleshooting."(page 237)