Mitsubishi Electronics PCFY-P24NKMU-E Closing a valve 1 → 2 → 3 → 4 →, Become OFF, Valve

<Output pulse signal and the valve operation>

Closing a valve : 1 → 2 → 3 → 4 → 1

Output

Output

(Phase)

Opening a valve : 4 → 3 → 2 → 1 → 4

1

2

3

4

The output pulse shifts in above order.

Φ1

ON

OFF

OFF

ON

Note:

Φ2

ON

ON

OFF

OFF

• When linear expansion valve operation stops, all output phase

Φ3

OFF

ON

ON

OFF

become OFF.

Φ4

OFF

OFF

ON

ON

• At phase interruption or when phase does not shift in order, motor

Linear expansion valve operation

does not rotate smoothly and motor will lock and vibrate.

• When the switch is turned on, 2200 pulse closing valve signal will

Open

be sent till it goes to point

in order to define the valve position.

D

C

• When the valve moves smoothly, there is no sound or vibration

occurring from the linear expansion valves, however, when the

(capacity)

pulse number moves from

to or when the valve is locked,

more sound can be heard than in a normal situation.

• Sound can be detected by placing the ear against the screw driver

positionValve

Close

Open

handle while putting the screw driver tip to the linear expansion

valve.

Outdoor unit R410A model

: 1400 pulse

A

Outdoor unit R22 model

: 2000 pulse

E

Opening a valve all the way

Close

B

Pulse number

Extra tightening (200~800 pulse)

Trouble shooting

Symptom				Check points		Countermeasures
Operation circuit	Disconnect the connector on the controller board, then con-					Exchange the indoor con-
failure of the micro	nect LED for checking.				6	troller board at drive circuit
processor					5	failure.
					4
					3
					2
				1kΩ LED	1
	When power is turned on, pulse signals will be output for 10
	seconds. There must be some defects in the operation circuit
	if the LED does not light while the signals are output or keeps
	lighting even after the signals stop.
Linear expansion	Motor will idle and make a ticking noise when the motor is					Exchange the linear expan-
valve mechanism is	operated while the linear expansion valve is locked.					sion valve.
locked.	This ticking sound is the sign of the abnormality.
Short or breakage	Measure the resistance between each coil (white-red, yellow-					Exchange the linear expan-
of the motor coil of	brown, orange-red, blue-brown) using a tester. It is normal if					sion valve.
the linear expansion	the resistance is in the range of 200Ω ±10%.
valve
Valve does not close	To check the linear expansion valve, operate the indoor unit					If large amount of refriger-
completely.	in fan mode and at the same time operate other indoor units					ant is leaked, exchange
	in cooling mode, then check the pipe temperature <liquid					the linear expansion valve.
				pipe temperature> of the indoor unit by the
				outdoor multi controller board operation
				monitor. During fan operation, linear expan-
			Thermistor	sion valve is closed completely and if there
			(Liquid pipe)	is any leaking, detecting temperature of
		Linear		the thermistor will go lower. If the detected
		expansion		temperature is much lower than the tem-
		valve		perature indicated in the remote controller,
				it means the valve is not closed all the way.
	It is not necessary to exchange the linear expansion valve, if
	the leakage is small and not affecting normal operation.
Wrong connection	Check the color of lead wire and missing terminal of the con-					Disconnect the connector
of the connector or	nector.					at the controller board,
contact failure						then check the continuity.

22