Mitsubishi Electric PQHY-P72TYHMU-A Service Handbook page 147

[ VII Control ]
Switch Function
Test run mode: en-
1
abled/disabled
Test run mode: ON/
2
OFF
CN51-3,5 signal out-
3
put switch
Water heat exchang-
SW3
4
er freeze prevention
5
6
7
8
9
10
1
2
Refrigerant amount
3
adjustment
Low-noise mode/
4 step demand switch-
SW4
ing
5
Cumulative com-
6 pressor operation
time data deletion
7
8
9
10
1) Unless otherwise specified, leave the switch to OFF where indicated by "-," which may be set to OFF for a reason.
2) A: Only the switch on either the OC or OS needs to be set for the setting to be effective on both units.
B: The switches on both the OC and OS need to be set to the same setting for the setting to be effective.
C: The setting is effective for the unit on which the setting is made.
3) The noise level is reduced by controlling the compressor frequency.
A setting of CN3D is required.(page 24)
4) If the inlet water temperature (TH7) drops below 5ºC [41ºF] while the compressor is stopped, or the outlet water temperature
(TH8) drops below 3ºC [37ºF], Cooling-only operation will be performed to prevent freeze-ups.
This operation will terminate when one of the following conditions is met: 1) Both the TH7 and TH8 readings (water tempera-
ture) exceed 10ºC [50ºF], 2) Two hours have passed since the beginning of the Cooling-only operation, or 3) Signal to resume
normal operation is received.
HWE09080
Function according to switch setting
OFF
SW3-2 disabled
Stops all ICs
Heat source unit er-
ror output
Ineffective
- -
- -
- -
- -
- -
- -
- -
- -
Normal operation
mode
Low-noise mode
(Note 3)
- -
Cumulative com-
pressor operation
time data is re-
tained.
- -
- -
- -
- -
Switch setting timing
ON OFF
SW3-2 enabled Anytime after power on
Sends a test-run After power on and when
signal to all IC SW3-1 is on.
Water heat ex-
changer coupling Anytime after power on
prevention output
Effective
Anytime after power on
Note 4
-
-
-
-
-
-
-
-
Anytime after being ener-
gized (except during ini-
Refrigerant amount tial startup mode.
adjust mode Automatically cancelled
90 minutes after com-
pressor startup)
Step demand mode Before being energized
-
Cumulative com-
Anytime after power on
pressor operation
(when the unit is turned
time data is delet-
on)
ed.
-
-
-
-
- 138 -
Units that re-
quire switch
setting
Note.2
ON OC OS
A -
A -
C C
A -
- - -
- - -
- - -
- - -
- - -
- - -
- - -
- - -
A -
C C
- - -
C C
- - -
- - -
- - -
- - -
GB