[Biggenz]

My A/C developed a leak some time ago, so I replaced the condenser first of all. Leak still there. As there was a strong smell of refrigerant in the cabin after I had it regassed, I thought it must be the evaporator leaking. I bought a new one but put the job off for over a year as it's such a pain in the ass to replace.

I finally pulled the trigger this week and fitted it on Monday. Went to have it regassed again, and this time the A/C no longer blows cold at all. It's as if the compressor has decided to die in the year I wasn't using the A/C. And on top of that I still have a leak as all the refrigerant has leaked out over two days.

I will get someone to do a leak test, but I'm more worried about it not working even with gas in. So I hooked up INPA and the only thing that looks suspicious is the Y-value that is showing -128. I've read previous posts where people had the same issue, but I don't think they ever got the bottom of it.

Does anyone have any ideas?

[Biggenz]

Actually, the Y-value changes if you press the Max button.

I've just gone through INPA again and there are no fault codes in any of the modules anywhere. The compressor relay engages when I turn the A/C on and I can also activate it in INPA itself.

There's actually still around 90psi of pressure on the high side which should be enough to activate the compressor? Only thing is when I checked the low side earlier today I barely got a reading so what does that mean?

[gbalthrop]

Originally Posted by Biggenz

... A/C no longer blows cold at all. It's as if the compressor has decided to die in the year I wasn't using the A/C. And on top of that I still have a leak as all the refrigerant has leaked out over two days...

You had SOME "Refrigerant Pressure", cleverly disguised as "Print Cooling Agent", per the Lower-Left bar graph on you first "Analog Inputs" Screen. That shows 6.5 Bar or ~ 94 PSIG refrigerant pressure, WHENEVER that ScreenPrint was saved. Your Engine was obviously running as KL30 Voltage was ~ 14V. BUT the compressor was NOT pumping. IF it HAD BEEN Pumping, Refrigerant Pressure would have been ~ 13 bar, and Evaporator Temp should have been ~ 10C or less.

6.5 bar would be a "Reasonable" system refrigerant pressure "At Equilibrium", with NO compressor "Pumping", and with High Side & Low Side pressures equal. That equilibrium pressure is normally attained after engine/ Compressor has been OFF for an hour or more.

If you have Manifold Gauges, or even a Can Tap with a gauge to read Low Side pressure, get a reading of BOTH High & Low Side Ports when engine has been off for an hour or more. IF the Refrigerant Pressure Sensor (located on High Side Line near the Washer Fluid Filler Tube) is reading correctly, that Value as received by JBBF & IHKA Modules should be SAME as High Side Port per Manifold Gauge.

You don't say if you read "Refrigerant Pressure" using INPA BEFORE you started the engine, so we can ONLY guess. If the JBBF & IHKA Modules are getting a pressure value from the Refrigerant Pressure Sensor of at least 3 bar, the compressor can be activated, as there is enough refrigerant to circulate Refrigeration (PAG) oil.

Unless the Compressor or its wiring/connector was damaged in some way, it SHOULD be activated with 6.5 bar "Equilibrium/Static" pressure in the system, per the P-Sensor signal.

I'm NOT aware of any specific screen in INPA via which you can "Activate" the Compressor, or view a value for the signal being sent to it via IHKA & JBBF Modules (Compressor AND Refrigerant Pressure Sensor are BOTH connected directly to the JBBF/JBE Module).

I would suggest using "Analog Inputs" screen (your first ScreenPrint) to view "Equilibrium" pressure, and report that value. Please also let us know if you have ANY UV Dye in the system, and whether you had any definitive "Leak" diagnosis of either the Condenser or Evaporator coils, before or AFTER removing the original coil (e.g. by dye appearing, or by Pressure Test of coil).

My PLAN would be to FIRST determine system pressure (INPA can easily show that per Pressure Sensor signal), then if that suggests a leak, add UV dye to try to identify leak source, such as Compressor Shaft or O-rings at fittings, and also test electrically to determine WHY Compressor is NOT pumping.

ANYONE know what "Y-Value" is and how it is computed?? It appears to be related to differential between T-Stat settings and Interior Temp, where large Negative Value appears with Coldest T-Stat setting, and large Positive Value appears with Hottest T-Stat setting.
George

[Biggenz]

I've had another think about it and I'm wondering whether the expansion valve is clogged up causing a blockage in the system.

Why else would I have pressure on the high side but nothing on the low side?

There must still be a leak as well which I'll hopefully get checked out tomorrow.

As for activating the compressor, under 'Engine' in you look under Actuator Activation 1, there is an option for Compressor Relay.

[mainbearing]

I do not know if the UK uses the same direct drive compressor as in the States.

If the system is not building pressure now and had lost its refrigerant in the year you did not run the AC, then I would think the pulley shear pin might have been broken because the compressor was essentially running without refrigerant (and therefore lubrication).

You can see if replacing the pulley would resolve it, if the compressor did not already spew metal throughout the system.

[Biggenz]

Originally Posted by mainbearing

I do not know if the UK uses the same direct drive compressor as in the States.

If the system is not building pressure now and had lost its refrigerant in the year you did not run the AC, then I would think the pulley shear pin might have been broken because the compressor was essentially running without refrigerant (and therefore lubrication).

You can see if replacing the pulley would resolve it, if the compressor did not already spew metal throughout the system.

Without any refrigerant in the system, the load on the compressor will be minimal as the swash plate will be vertical meaning no internal piston movement, and therefore no internal pressure. Since the drive plate on mine is still intact and there is no obvious signs of overload protection having been triggered, I can only assume my compressor is still ok.

From what I understand, the compressor can run fine in this state with minimal oil for some time as the oil has nowhere to go. Please correct me if I'm wrong anyone.

Also, I would have thought that if the internal valve or solenoid has failed, it should possibly store a fault code of some sort? As mentioned before, there are no fault codes stored at all.

[Biggenz]

Originally Posted by mainbearing

I do not know if the UK uses the same direct drive compressor as in the States.

If the system is not building pressure now and had lost its refrigerant in the year you did not run the AC, then I would think the pulley shear pin might have been broken because the compressor was essentially running without refrigerant (and therefore lubrication).

You can see if replacing the pulley would resolve it, if the compressor did not already spew metal throughout the system.

I've just had the auxiliary belt off and you're right, the compressor is dead. Even though there is no sign of a catastrophic failure, the compressor had seized and the overload protection kicked in. The pully is spinning freely and no longer connected to the input shaft.

After I buy a new compressor, I will have replaced the entire A/C system apart from the pipes. FML

[mainbearing]

Hopefully a new compressor solves your problem.

Variable compressors actually do not de-stroke down to 0. It will always operate at a few percent capacity. If there is no refrigerant, oil does not circulate and the compressor will seize. Sounds like that was what happened to yours.

I keep an eye on these variable systems like a hawk. I never let these systems run low on refrigerant. A couple of ounces 3-4 years apart is usually sufficient. I am not sure you can DIY that in the U.K.