54
HIGH PRESSURE SHUTDOWN - HEATING
HIGH PRESSURE ALARM
Air flow sufficient ?
( Indoor unit )
Check condenser coil
(1)
Check fan
( 2 )
Check air flow
- filters - ducts ( 3 )
SI NO
Indoor air temperature STD?
Correct Refrigerant charge ?
No impurities present ?
Suction temperature and/or
pressure OK ?
Unit operates correctly
Check
liquid subcooling
( 5 )
Repeat vacuum and charge
( 6 )
Check operation of outdoor
unit ( 7 )
Check condition of cut-off
valves on liquid line
( 8 )
Check the project data
( 4 )
NO
NO
NO
NO
SI
SI
SI
SI
Notes:
1) It is essential that there is a maximum heat exchange, the coil must therefore be free of dirt, scaling or anything that may
impede the air flow.
2) Check that the direction of rotation is correct and the condition of the fan, if damaged it must be replaced.
3) Check the airflow is conform to the project data. Check the air filters are not dirty or that nothing is obstructing the air ducts.
4) The heating range corresponds to a minimum and maximum condensing temperature. Check the indoor unit is within these
limits.
5) See the STARTUP manual for the check procedure.
6) One problem involves a very high condensing temperature (25/30 degrees above the outdoor air temperature) combined with
poor cooling. The symptoms are the same as with excessive refrigerant. Check the charge and examine this possibility if it is
correct, repeat the vacuum and gas charge proceedure (see STARTUP manual).
7) Check the airflow is modulated regularly in relation to the temperature.
8) Check that all the cut-off valves on the liquid line are completely open. The filter dryer has a two-way operation, check that it
is not blocked by controlling the temperature difference around the filter.
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