Toshiba MMU-AP0091H service manual Operation Start/Operation End

6-2. Outdoor Unit

6-2-1. Operation Start/Operation End

The compressor, solenoid valve, pulse motor valve (PMV), outdoor fan, etc. are controlled by a command from the indoor controller. The follower outdoor unit starts/stops by a command from the header outdoor unit.

No.	Item	Operation explanation and applied data, etc.				Remarks
1	Pulse Motor Valve	(1) PMV control (using two PMV, 1 and 2)				• During heating operation,
	(PMV) control	• Each PMV is controlled between 90 to 1000 pulses				PMV2 is 0 pulses and
		during operation.				PMV may be controlled
		• In cooling operation, PMV opening is dependent upon				with only PMV 1, with a
						minimum of 45 pulses.
		detected readings from the TL sensor and Pd pres-
		sure sensor (sub-cool control).
		• In heating operation, PMV opening is dependent upon
		detected readings from the TS and TD sensors and
		the Ps pressure sensor (super-heat control).
		• Each PMV will be fully closed when the system is in
		‘Standby’ or ‘No demand’ modes and when a malfunc-
		tion in the system has occurred.
			1000
		PMV opening		PMV 2
			550
			500
			90	PMV 1
			45
			Min.	Med.	Max.

(2) PMV3 control

1)	PMV3 (Pulse Motor Valve 3) is controlled between 0
	to 500 pulses during mainly cooling, part heating or
	mainly heating, part cooling operation.
2)	PMV3 opening is controlled according to the demand
	capacity difference (HP) between the cooling
	capacity and the total heating capacity.
3)	The PMV will be fully closed when the system is in
	‘Standby’ or ‘No demand’ modes and when a mal-
	function in the system has occurred.
2 Outdoor fan control (1) Fan control in all cooling operation
1)	The outdoor fan speed/mode is determined by the	When TE temp. (ambient
	detected Pd pressure value.	temperature) exceeds 25°C,
2)	When cooling operation has started, the outdoor fan	Heating operation stops.
	speed of the master unit is controlled using the
	detected Pd pressure value.
(2) Fan control in all heating operation
1)	The outdoor fan speed/mode is determined by the
	detected TE sensor value.
2)	If a TE value > 25°C has been continuously detected
	for 5 minutes, the operation may stop.
3)	After start up, this control is not available during the
	specified time after a defrost operation.
4)	This operation may start and stop repeatedly when
	the system is undercharged.
(3) Fan control for mainly cooling, part heating operation		• The maximum fan speed
The outdoor fan speed (mode) is controlled according to		differs depending on the
the target of the Pd (Discharge pressure).		outdoor HP.

64