MITSUBISHI ELECTRIC P500YMF-C - Manual (Page 147)

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Note 1 Wait until the units stabilize as described in the refrigerant amount adjustment procedure in “Chapter 6 ”.
Note 2 After the units are operating stably, check that the refrigerant composition of
α
OC is within the following
ranges, indicating that the composition check is finished.
If the accumulator liquid level AL = 0 when cooling:
α
OC = 0.20 ~ 0.26
If the accumulator liquid level AL = 1 when cooling:
α
OC = 0.23 ~ 0.34
When heating:
α
OC = 0.25 ~ 0.34
(The self-diagnosis switch (SW1) on the main board of the outdoor unit can be used to display this data on
the LED.)
[
α
OC self-diagnosis switch]
Note 3 TH2 and TH9: Check and make any corrections using the same method as that for a faulty temperature
sensor, (refer to TROUBLESHOOTING).
LPS: Check and make any corrections using the same method as that for a faulty low pressure
sensor, (refer to TROUBLESHOOTING).
CS circuit block: Set the self-diagnosis switch on the outdoor MAIN board as shown below.
• Check and make any corrections so that “0” is displayed.
• If any number other than 0 is displayed and TH2, TH9 or LPS are malfunctioning, correct them, then set
SW2-9 on the MAIN board of the outdoor unit from OFF to ON.
• If any number other than 0 is displayed and TH2, TH9 or LPS are not malfunctioning, replace the CS
circuit if refrigerant is not flowing through it (while operating) and set SW2-9 on the MAIN board of the
outdoor unit from OFF to ON.
Note 4 If it can be verified that R407C was correctly charged in the liquid phase, continue to Yes. If there is a
possibility that it was not charged correctly, such as with a gas charger, continue to No.
Note 5 After reclaiming the system’s refrigerant, extract the air to create a vacuum, then refill with new refrigerant.
Be sure to charge in the liquid phase. In addition, be sure to change the dryer.
Note 6 After the units are operating stably, check that the refrigerant composition of
α
OC is within the following
ranges, indicating that the circulation check is finished.
If the accumulator liquid level AL = 0 when cooling:
α
OC = 0.21 ~ 0.25
If the accumulator liquid level AL = 1 when cooling:
α
OC = 0.24 ~ 0.28
When heating:
α
OC = 0.27 ~ 0.31
If the refrigerant composition of
α
OC is not within the ranges specified above, a large error has been
detected. Refer to section 1-3 in Chapter 6 , then after setting SW4-1 on the MAIN board of the outdoor unit
to ON, calibrate the refrigerant circulation constant
α
OC with SW4-2 until it is within the ranges specified
above.
After calibrating, keep the SW4-1 ON and finish the circulation check.
α
OC>
Conditions: If the accumulator liquid level AL = 0 and
α
OC = 0.29 when cooling,
α
OC must be adjusted so
that it is between 0.21 and 0.25.
By switching SW4-2 between ON and OFF, adjustments can be made in the following order:
0
→
3%
→
6%
→
9%
→
12%
→
-6%
→
-3%
→
0
For this example, by making an adjustment of -0.06 (-6%),
α
OC can be adjusted to 0.23.
1. If SW4-2 is already set to OFF, change the switch 5 times.
OFF (0.29)
→
ON (0.32)
→
OFF (0.35)
→
ON (0.38)
→
OFF (0.41)
→
ON (0.23)
2. If SW4-2 is already set to ON, change the switch 5 times.
ON (0.29)
→
OFF (0.32)
→
ON (0.35)
→
OFF (0.38)
→
ON (0.41)
→
OFF (0.23)
1
ON
2 3 4 5 6 7 8 9 10
1 2 3 4 5 6 7 8 9 10
ON