Daikin Altherma 3 M - Low Pressure Switch; Checking Procedures

3 | Components
Service manual
167
EBLA09~16DA + EDLA09~16DA
Daikin Altherma 3 M
ESIE20-06A – 2021.03
Is the problem solved? Action
No Return to "3.12.1Checking
procedures"[4160] of the hydro PCB
and continue with the next procedure.
3.13 Low pressure switch
3.13.1 Checking procedures
To perform an electrical check of the low pressure switch
Prerequisite: Stop the unit operation via the user interface.
Prerequisite: Turn OFF the respective circuit breaker.
Prerequisite: Remove the required plate work, see "3.17Plate work"[4230].
1 Recuperate the refrigerant from the refrigerant circuit, see "4.2.2 Repair
procedures"[4291].
2 Connect a vacuum pump to the gas service port of the refrigerant circuit and
vacuum to just above operating pressure of the low pressure switch.
a
bef
d
c
a Low pressure switch protection control
b Pressure
c Low pressure switch closed
d Low pressure switch open
e Low pressure switch reset pressure
f Low pressure switch operating pressure
Low pressure switch Operating pressure (MPa) Reset pressure (MPa)
S1PL −0.05~−0.01 0.02~0.08
3 Disconnect the low pressure switch connector from the appropriate PCB.
4 Measure contacts between the pins 1‑2 of the low pressure switch connector.
Result: The switch MUST be closed.
5 Vacuum until pressurized just below operating pressure of the low pressure
switch.
6 Measure again contacts between the pins 1‑2 of the low pressure switch
connector.
Result: The switch MUST be open.
INFORMATION
If the low pressure switch was triggered open, it will stay open until the refrigerant
pressure rises above the reset pressure of the low pressure switch.
7 Fill the refrigerant circuit with nitrogen until pressurized just below reset
pressure of the low pressure switch.