HEXA

HVAC

LINEAR POWER MODULE (LPM)

In case of FATC a LPM is used to enable the ECU to

control the blower speed in smaller increments. It is

mounted in the same location as blower resister.

PIN OUT

PIN NO

DESCRIPTION

Ground

Signal

Battery

Motor Negative

Motor Positive

NOTE

For more information on LPM refer FATC section in

this group.

EVAPORATOR COIL AND TXV

(THERMAL EX-

PANSION VALVE)

EVAPORATOR COIL

It is a heat exchanger cum dehumidifier which ab-

sorbs heat and moisture of the air passing through it

to give cold dehumidified air. As the refrigerant ab-

sorbs the heat it changes its state from liquid to

vapour. A thermister (

temperature sensor)

is used to

measure the temperature of the air passing over the

evaporator in order to avoid freezing.

TXV (

THERMAL EXPANSION VALVE

)

The thermal expansion valve used in this vehicle is

block type valve. It consists of a two passages one

for refrigerant flowing into the evaporator and the

other for refrigerant coming out of evaporator and

into the compressor. A temperature sensing element

is placed in the outlet passage. This sensing element

is filled with a fluid which expands and contracts

when there is rise or fall in the temperature. When

the temperature of the refrigerant flowing out of the

evaporator rises it causes the expansion of the re-

frigerant in the sensing element which in turn pushes

the pin, such that the ball valve blocking the orifice

opens to allow more refrigerant into the evaporator.

The pressure spring provided below the ball tends to

close the ball valve and hence this pressure has to

be overcome in order to open the valve.

There is a passage in the block valve where refriger-

ant flowing out can build pressure under a

diaphragm on which the sensing element is mounted

causing the diaphragm to move up; this provides the

needed pressure correction while regulating the re-

frigerant into the evaporator.