HVAC - AC not blowing ice cold.

strummagnet · #1 11th May 2023, 01:33 PM

Hi. I should have noticed this before, weather not being warm enough, but my HVAC unit or the AC bit is not blowing ice cold.

I have:

Checked fuses - no issues
Run a scan on the HVAC unit - No codes present
Visual inspection - all seems good - no loose connections

Cycled through the options, switching ECON on or off does not not seem to indicate any changes to the compressor. I checked the compressor fuse (drivers footwell) and that is OK. Are there any other connections I should be looking at?

Saff · #2 11th May 2023, 02:46 PM

Hi Paul
If the compressor is not kicking in and the fuse is ok then my VERY limited understanding suggests either the gas is low/flat or I seem to remember if the cooling fans aren't working then the compressor won't run. Hope that's some help. Steve

MikkiJayne · #3 11th May 2023, 03:03 PM

Is the compressor spinning?
Is the electric fan on?
Is it cooling at all?
Condensation on the pipes past the header tank?
Is the centre vent switching between hot and cold?

If it'll switch ECON on/off then the HVAC unit thinks there is enough gas, which comes from the pressure switch on the evaporator.

Its becoming increasingly common for the valve blocks to fail and allow hot water through constantly, meaning even if the AC is running ice cold, you still get a face full of hot air. Marcel and I are working on a solution for this which is not tested yet.

strummagnet · #4 16th May 2023, 05:34 PM

Quote:

Originally Posted by MikkiJayne

Is the compressor spinning?
Is the electric fan on?
Is it cooling at all?
Condensation on the pipes past the header tank?
Is the centre vent switching between hot and cold?

If it'll switch ECON on/off then the HVAC unit thinks there is enough gas, which comes from the pressure switch on the evaporator.

Its becoming increasingly common for the valve blocks to fail and allow hot water through constantly, meaning even if the AC is running ice cold, you still get a face full of hot air. Marcel and I are working on a solution for this which is not tested yet.

Is the electric fan on? Yes, running fine.
Is it cooling at all? Not cooling at all, fan on high speed.
Condensation on the pipes past the header tank? No condensation, pipes appear to be warm to touch.
Is the centre vent switching between hot and cold? No discernible difference when switching from warm to cold on centre vent.

Am I looking at Valve block replacement or finding a learned AC person?

strummagnet · #5 19th May 2023, 02:49 PM

Well this became odd. Sort of.

Took the car in to be checked out and it was found there was very little gas to recover from the system. Lines were checked for leaks and none present.

Refilled and has been ice cold for the last 24hrs with all controls working.

Sorry if I mis-directed you chaps.

tintin · #6 19th May 2023, 03:32 PM

Quote:

Originally Posted by strummagnet

Well this became odd. Sort of.

Took the car in to be checked out and it was found there was very little gas to recover from the system. Lines were checked for leaks and none present.

Refilled and has been ice cold for the last 24hrs with all controls working.

Sorry if I mis-directed you chaps.

Sounds like a good outcome - especially given the weather/forecast

MikkiJayne · #7 19th May 2023, 04:19 PM

Vexing because it had numerous new parts and seals. It might need some dye injecting and then going over with a blacklight to see if the leak is visible.

Saff · #8 19th May 2023, 04:35 PM

Sounds a bit like my D4, tested ok for leaks but only about 70g of gas recovered. Refilled to I think 780g.
Glad you're all sorted.

strummagnet · #9 20th May 2023, 08:54 AM

Quote:

Originally Posted by MikkiJayne

Vexing because it had numerous new parts and seals. It might need some dye injecting and then going over with a blacklight to see if the leak is visible.

Yes it threw me as you put new condenser, dryer and compressor on. The fact it switched from ECON to normal (though no difference); I thought the worst.

Quote:

Originally Posted by Saff

Sounds a bit like my D4, tested ok for leaks but only about 70g of gas recovered. Refilled to I think 780g.
Glad you're all sorted.

Hopefully that's sorted it. The 'Aircon' chap said there were no 'discernible' leaks but it wasn't fully tested.

steamship · #10 11th May 2023, 05:54 PM

Quote:

Originally Posted by strummagnet

Run a scan on the HVAC unit - No codes present

I'm sure there was somewhere in the measuring blocks where it gave the refrigerant pressure value, but can't find it. Something similar to this video from the 22 second mark:

https://youtu.be/H9wJNAJBcvI?t=22

Turns out, if I switch my ECON off, the engine stalls. I'm hoping that this is because there is no gas in the system (after having the front off), and it just needs pressure tested and regassed, and not issues with the compressor.