A/C Bulb Broken, What are my options?

Avery · 03-30-2003, 08:49 PM

Hello All:

The little capillary tube is broken on a used A/C Unit that I purchased. This is the tube that runs to the A/C temp control. I think I may have broken it while unpacking the stuff from the box. Can this thing be purchased? If so, who are potential suppliers? What happens if I don't replace it? Will the A/C unit work as if it's on full blast (OK with me) or as if I have it on the least cold setting? Any advise is much appreciated.

Felmir

Jim Sims · 03-31-2003, 03:39 AM

You'll need to replace it and probably you'll also need to replace the thermal expansion valve (TXV) it controls. Without the capillary (bulb) system of the TXV fuctioning correctly the system will likely flow little or no refrigerant and provide no cooling. If it were to be stuck open (which I don't believe to be the case with a failed capillary) there is the risk of sending liquid refrigerant into the compressor which can cause the compressor to self destruct. Check with Griffiths, Performace Aire, and other Porsche after market A/C parts and system suppliers. Cheers, Jim

stormcrow · stormcrow's Garage

Are you talking about the capillary tube on the fan control switch or on the expansion valve. If it's on the expansion valve, the expansion valve needs replacing. If it's on the fan control switch, then the switch needs replacing.

The fan control switch capillary tube has a gas in it which controls the on/off function of the compressor. When the air temp is warm, the gas in the capillary tube expands and keeping the compressor running. As the air temp becomes colder, the gas in the capillary tube contracts shutting the compressor off.

With regard to the expansion valve capillary tube, it does basically the same thing but it controls the refrigerant going throuth it. If the temp on the return side of the system is warm with reference to its design, then it opens the valve to let more refrigerant through it. As the temp becomes lower, then the refrigerant flow is restricted, again based on design, to reduce flow.

Replacement parts - if you need an expansion valve I believe Pelican sells them. If you need a new switch, then you may have go to to a P-dealer or aftermarket supplier for one.

You could use a window unit a/c switch but you would only have one speed and you would need to know how to wire it. You may also be able to cannibalize a switch from a junk yard.

Steve

"A Porsche does more then just go fast in a straight line"

dkmartin · 03-31-2003, 10:20 AM

What Steve said...except if it is a 84-86 model, I believe the tube is connected to the temp. switch dial NOT the fan speed switch...so....if this is the case, turn on the a/c with both the fan speed switch AND the temp. switch on high and check to see if compressor clutch is engaged. If so, let it run for awhile to see if it turns off....if it gets really cold inside the cabin and the compressor is still running, then what you have is an a/c system with no temperature regulation, it's either on or off and controlled by the fan speed switch: Fan switch off= a/c off...fan switch on medium speed= a/c on with fan blowing medium speed.

stormcrow · stormcrow's Garage

Doug is right, I don't know what I was thinking. On my 78, the temp is controlled by one switch, the fan by the other.

Steve

"A Porsche does more then just go fast in a straight line"

Avery · 03-31-2003, 07:36 PM

Thanks everyone for the advise so far. Sounds like I'll have to replace the bulb and the temp control (not expansion valve). I'm hoping this is not expensive.

Felmir