Mitsubishi Electric PRH-P8MYA Technical & Service Manual page 72

Symptom and operation when normal
7. Remote controller display is normal
and heating operation is performed
but without any capacity (does no
heat).
Cause
(1) Insufficient refrigerant.
(2) Refrigerant piping heat insulation insuf-
ficient.
t
(3) Filter clogged.
(4) Indoor-side heat exchanger clogged.
(5) Air duct short cycle.
(6) LEV malfunction
- 69 -
Symptom judgment and remedy
(1) - Since the discharge temperature rises when
there is leakage, judge by measuring the tem-
perature.
- Check piping connections, etc. for gas leak-
age.
(2) Check heat insulation.
(3) Open intake grille and check filter.
Clean filter, and remove dust and dirt.
(4) - Since the indoor-side piping temperature
and outlet pressure rise when the heat
exchanger is clogged, judge by measuring
the outlet pressure.
- Clean heat exchanger.
(5) Remove obstruction.
(6) Check refrigerant circuit operation state.