MF7480 Faulty Air Con

[Jinty Mcginty]

Air Con has stopped working it is a climate control version. When you switch the air con on you can hear the compressor clutch kicking in but it just blows hot air.
Any ideas where to start. Had an issue last year with water dripping out of roof panel on hot days but maybe a choked drain line.

 

[Lofty1984]

Have you tried turning the tap off under cab could be letting hot water through the system

 

[Timbo]

Does the compressor remain engaged, or is it rapidly cycling? Does it blow cold at first start up then get warmer as engine warms up or just not at all ?

 

[Jinty Mcginty]

Does the compressor remain engaged, or is it rapidly cycling? Does it blow cold at first start up then get warmer as engine warms up or just not at all ?

Compressor remains engaged but does not blow cold at all

 

[Jinty Mcginty]

No tap unfortunately if I knew the bore size I should fit a tap

 

[box]

Has it just stopped working suddenly (i.e. it was cold yesterday and hot today) or has it happened gradually? Or has it not been used for a while?

Turn the A/C on, put your hand on the pipes at the back of the compressor and tell us whether they're hot or cold.

 

[Timbo]

Compressor remains engaged but does not blow cold at all

Is the suction line back to the compressor ( larger one ) sweating after its been running afew minutes ?

 

[Jinty Mcginty]

One pipe is ice cold the other one nearly burn your hand on

 

[TripleSix]

Sounds like the heater is stuck on.
Pinch off a pipe with vice grips and see what happens

 

[Jinty Mcginty]

Clamped 1 pipe going up to cab helped a little still blowing warm though.left tractor ticking over and now compressor is cycling every 10 secs and water dripping out of roof [emoji35]

 

[Timbo]

Clamped 1 pipe going up to cab helped a little still blowing warm though.left tractor ticking over and now compressor is cycling every 10 secs and water dripping out of roof [emoji35]

Clamp both

 

[Rob Holmes]

@TNSmassey

 

[Jinty Mcginty]

Clamp both

Tried clamping both possibly a little better but still blowing warmish air.
One pipe at back of compressor is ice cold and sweating other one is pretty hot.
You would think from that it must be something up in the roof ?

 

[box]

You would think from that it must be something up in the roof ?

Probably. Pull the top off and see what's going on. Evaporator core should be cold (but not iced up), heater tap should be off and the heater core should be ambient temperature or thereabouts.

Unblock the drain while you're up there.

 

[Timbo]

Tried clamping both possibly a little better but still blowing warmish air.
One pipe at back of compressor is ice cold and sweating other one is pretty hot.
You would think from that it must be something up in the roof ?

Yes. A/C system is working fine on the face of it.

 

[Colliedog]

Have you got another tractor to compare how much air is being blown through the vents? You can get these symptoms with a blocked matrix. Dust, hay and dog hair can often build a mat and restrict air flowing though.

 

[davidroberts30]

Yes lift the roof then open the heater box
Guaranteed the matrix is blocked

 

[Jinty Mcginty]

Yes lift the roof then open the heater box
Guaranteed the matrix is blocked

What like a task to clean it
Just an air line ?

 

[davidroberts30]

Airline maybe a brush

What like a task to clean it
Just an air line ?

ush

 

[Jinty Mcginty]

Found the problem up in the roof water valve jammed open
Took stepper motor off twisted valve forward and back with an allen key put motor back on and hey presto all good
Thanks everyone for the advice