Another stupid Air Con question.

[Nathan Buffery]

So as previously established the Air Con on the Mk3 Focus is pants. I've replaced the condenser and I do have relatively cool air blowing out the vents. However, when I was investigating where the cabin filter is, I discovered that one of the water pipes that go into the heater assembly was hot, while the heater control is set to cold with the Air Con on.  I was wondering if this should be hot or is the valve that controls the temperature in the car not working. I'd be interested to know if anyone else with the maunal heater (twisty knobs) has hot pipes next to the clutch pedal, while the Air Con is on.

[richardc1983]

One of the pipes will be hot as it is the heater matrix coil. 

[Frowma]

I'm not 100% sure but this does sound right, the valve / flap that controls the hot / cold (not air-con) is in the box that the pipes go in, so the pipe is always going to be hot as it is coming from the engine and feeding the matrix. When you set the temp to cold it'll just change the flap to direct cold air straight from the outside (or recirculate the cabin air) rather than from round matrix that the hot pipe feeds.

When you have it set to fully cold with the air-con on, the pump starts to circulate the coolant and the fan will blow over the cold pipes to provide the cold air. Does the condenser unit contain the pump as well? If not then the pump might be on the way out.

[Nathan Buffery]

24 minutes ago, Frowma said:

I'm not 100% sure but this does sound right, the valve / flap that controls the hot / cold (not air-con) is in the box that the pipes go in, so the pipe is always going to be hot as it is coming from the engine and feeding the matrix. When you set the temp to cold it'll just change the flap to direct cold air straight from the outside (or recirculate the cabin air) rather than from round matrix that the hot pipe feeds.

When you have it set to fully cold with the air-con on, the pump starts to circulate the coolant and the fan will blow over the cold pipes to provide the cold air. Does the condenser unit contain the pump as well? If not then the pump might be on the way out.

So the temperature control diverts the Air flow rather than the hot water circulation? I guess that makes sense. The pump is separate from the condenser.

[TomsFocus]

Yep, the heater matrix is always hot....which is why the dash (particularly by your leg) feels hot even with the AC blasting out cold air! 

[Nathan Buffery]

1 hour ago, TomsFocus said:

AC blasting out cold air!

Yeah I remember blasting out cold air...that was on my mk1 focus though🤔!!

[Ned_Mk2_1.8tdci]

33 minutes ago, Nathan Buffery said:

Yeah I remember blasting out cold air...that was on my mk1 focus though🤔!!

When is the last time your AC was checked for refrigerant, compressor oil etc......

Remember for the future, there's no stupid questions, only stupid answers! 

[Nathan Buffery]

31 minutes ago, Ned_Mk2_1.8tdci said:

When is the last time your AC was checked for refrigerant, compressor oil etc....

I had it done when I fitted my new condenser. It's not got any worse, it's just not as cold as my old mk1 used to be, but going by previous comments on this forum, the system on the mk3's is not very good.