Hbc Maintenance Instructions (Applicable To Main And Sub Hbcs); Valve Block - Mitsubishi Electric PURY-M200YNW-A1 Service Handbook

[8-14 HBC Maintenance Instructions (Applicable to main and sub HBCs) ]

8-14 HBC Maintenance Instructions (Applicable to main and sub
HBCs)
8-14-1

Valve Block

VB3 (valve block) is driven by the pulse signal from the VB board and are controlled by a stepping motor.
1) VB board and valve block (VB3)
Valve block
4
3
Limit signal
2
(Opening
"0" signal)
1
2) Pulse signal output and valve motion
Output (phase)
number
4
5
7
8
If the LEDs (VB3a-VB3p) on the VB board are lit, check the relevant valve blocks for loose connectors and faulty wiring. Make
sure that the valve blocks are properly controlling the refrigerant flow.
If the LED is unlit, check all valve blocks for proper operation.
If the problem persists after taking the above measures, replace the circuit board.
3) Opening and closing of the valve
BS_08_L
5
M
6
6 7
8
Output status
1 2 3
ON ON OFF
OFF ON ON
OFF OFF ON
ON OFF OFF
Cooling
Closing
the valve
Opening
the valve
0
Circuit board
8
7
6
5
4
3
2
LED
1
GND
4
OFF When valve opens (0 → C800 or H800): 4 → 3 → 2 → 1
OFF When valve closes (C800 or H800 → 0): 1 → 2 → 3 → 4
ON
ON
Heating
Opening
the valve
700 800 900
Number of pulses
12V
12V
Microcomputer
Closing
the valve
1600
chapter 8 -
127