Carrier MMY-MAP0724FT9UL Service Manual page 67

NO. Item
11 A3-IPDU
IPDU controls inverter compressors by issuing commands relating to compressor
control speeds, speed increases/decreases, and current release control values via the
interface P.C. board.
The main control functions of the IPDU P.C. board are described below.
1. Current release control
To prevent inverter input current from exceeding the specified value, output
frequency is controlled with AC input current as detected by T02 mounted on the
control P.C. board.
Current control values for various outdoor units are shown below.
2. Heat sink temperature detection control
1) This control function is aimed at protecting IGBT from overheating via a
2) When TH ≥ 185°F (85°C) is detected, the fan operation mode is raised by one
3) After step 2), the normal fan mode is restored when TH falls to < 176°F (80°C).
4) When TH ≥ 221°F (105°C), compressors are shut down.
5) Compressors are restarted 2 minutes and 30 seconds later, with an error count
3. Overcurrent protection control
1) When the overcurrent protection circuit on an IPDU P.C. board detects an
2) The compressor is restarted 2 minutes and 30 seconds later, with an error count
3) If the error count reaches 8, the error is confirmed as final.
4. High pressure SW control
1) When the high pressure SW of an inverter compressor is activated, the
2) The compressor is restarted 2 minutes 30 seconds later, and, if it successfully
3) If the error count reaches 4, the error is confirmed as final. The error "P04" is
Specification outline
Current
I
1
I
2
Zone A:Compressors are operated normally.
Zone D:The current operating frequency is maintained.
Zone B:Operating frequency is lowered.
Zone C:The lowering of operating frequency is halted
to maintain the current frequency.
Outdoor unit
Ton capacity
10
8
6
thermistor (TH sensor) mounted in the compressor drive module (Q201) of A3-
IPDU.
step, followed by a series of additional step-ups right up to the highest mode at a
rate of one step/5 seconds.
of 1 recorded. If this is repeated four times (error count reaches 4), the error is
confirmed as final. The error [P07] is displayed. (There will be no more restarts.)
* Possible causes of the confirmed error include a heat buildup in the outdoor
unit, fan abnormality, blockage of the cooling duct, and IPDU P.C. board fault.
* The TH temperature used in this control function is the highest registered by
A3-IPDU1, A3-IPDU2, and A3-IPDU3.
abnormal current, the compressor is shut down.
of 1 recorded. If the compressor successfully operates for at least 10 minutes
after a restart, the error count is cleared.
compressor is shut down with an error count of 1 recorded.
operates for at least 10 minutes, the error count is cleared.
displayed.
Zone B
Zone C
Zone D
Zone A
FT9UL (208/230V) FT6UL (460V)
I1 I2 I1
14.5 14 7.1
14 13.5 6.7
13.9 13.4 6.6
– 67 –
I2
6.6
6.2
6.1
• A3-IPDU1, 2 and
3 are each
provided with a
TH sensor.
• Connected to A3-
IPDU, the high-
pressure SW is
normally closed.
Remarks