Air Conditioning problem

[Mpierick]

I am having an electrical problem with my air conditioner. My compressor will not engage. I can put power direct to the 9 pin and the clutch engages. When I measure the power that goes to the high pressure switch it reads 10.4v Is that enough to engage the clutch? If not what is my next move.

Thanks.

Mike P

[Mrmerlin]

are there air bubbles in the sight glass? with the compressor jumpered?
Has the HVAC board relay been replaced?
google 928 HVAC relay replacement

[Mpierick]

I have evacuated the system. And I put a vacuum on and it held pressure. I then tried to put some freon in. I noticed the clutch would not engage. That is when I started the voltage test.

Where is the HVAC board relay?

Thanks. Mike P

[Mrmerlin]

google 928 HVAC relay replacement.

NOTE with the system empty of freon it may take a short while for the freon gas to increase the pressure in the lines to turn on the low pressure switch,
once this turns on,
then the compressor will engage,
that is if everything else is in working order.

[Mpierick]

is it a problem if I am only getting 10.4v at the high pressure switch?

Thanks for all your help.

Mike P

[Mpierick]

I found the relay. I will start the replacement.

Thanks Mrmerlin

[AirtekHVAC]

Mike,

Let me know if you need a hand....

[Mrmerlin]

the only thing i could advise on the wire install into the board is,
Do not drill the holes bigger as this will usually rip the bonded circuitry off the board your first hole will confirm this. BTDT

[Mpierick]

I had an extra contoller and now I am getting 12v to the high pressure switch. I pulled a vacuum again and tried to put some freon in. It would not go in. I converted the system over to 134. Replaced all the O rings and the ports. I am thinking that maybe my gages are not reaching the shrader valve to open it up to put freon in. Could that be the problem?

Also, Has anyone extended the low pressure access port so it can be reached easier.

Thanks Ron for the offer. Long time no see. I will be calling you. How is .#30 doing?

Thanks. Mike P

[Mrmerlin]

OK lets get things straight here are you installing freon or 134?
Freon has different connectors for the lines,
134 takes a bigger connection fitting and your Freon connectors wont connect to the 134.
Its possible that your lines are not opening the schrader valves do you hear any gas hiss when you connect the lines? What type of connection do you have on the 134 can.
Will you post pictures of the hoses and can fitting your using

[Mpierick]

Mrmelin,

I am sorry I assumed freon is a generic term. I am installing 134. I have changed out all the connections to handle 134. The larger connections. The low pressure valve is very difficult to access. Is it possible the extend the connection above the coolant line.

Thanks. Mike P

[Mrmerlin]

Dichlorodifluoromethane
Dichlorodifluoromethane, is a colorless gas, and usually sold under the brand name Freon-12, is a chlorofluorocarbon halomethane, used as a refrigerant and aerosol spray propellant. Wikipedia
Formula: CCl2F2
Boiling point: -21.64°F (-29.8°C)
IUPAC ID: Dichlorodifluoromethane
Density: 1.49 g/cm³
Molar mass: 120.91 g/mol
Soluble in: Water

[Mpierick]

Well, I think I found one of my problems. I was wondering if my gauges were pushing the schrader valve down, so I screwed the schrader valve out a little and hooked up my gauges. I was able to evacuate it and also put some 134 in it. The clutch looked like it engaged. My problem now is that the schrader valve is not tight and it will leak.

Any Ideas? Are there longer schrader valves? or different 134 connections.

Thanks. Mike P

[Mrmerlin]

screw the schrader back in and then put a cap on it

[AirtekHVAC]

Sorry mike, been traveling today. Do you have a schraeder tool? Once you evacuate and recharge, you can tighten the schraeder back up, and do as Merlin said and cap it...won't hurt a thing, and will just hiss whenever you remove the cap again ( just remove slowly) if it is leaking a little. How old are your gauges? Sometimes the depressor in the end of the hose pushes too far into the hose fitting and won't compress the schraeder. There are a few different sized schraeders and depressors...I have a kit...we need to hook up for lunch one day and I'll let you pick through it.

I am sure there is a way to extend the fitting...might not be easy, and might have to evacuate it all again.....

#30 been sitting on her lift bars doing nothing. Rebuilding rear shift linkage this week, putting it in Saturday afternoon, (I hope), then have to figure out how I am going to do the clutch line and blue hose. Have not started her in 3weeks.....I bet she will run rough when I fire her off....

[Mpierick]

Thanks a lot Mrmerlin and Ron!!!!

I will do that in the next day. By the way I have some cheap gauges. That also might be my problem with the valves.

Ron, sounds good. Lets get together for lunch. Give me a call.

Thanks.

[19psi]

I run into that problem all the time with any type of quick connect fittings designed to keep refrigerant in the hose. For standard R12 fittings, I always use regular hoses. No real loss on the low side as long as the compressor is running when you remove it and you're not second guessing yourself when pulling a vacuum. If you have at least one standard hose, ditch those 134a adapters. Or try a different brand of 134a adapter. Some of the cheaper ones are known to cause problems.

FREON is nothing more than a generic name owned by DuPont. It does not specifically mean R12.

[Mpierick]

Thanks 19psi. You are exactly right. The Schrader valve was not being pushed in so I was pulling a vacuum on the hose. I though I was pulling a vacuum on the system but it was only on the gauge hose. I do not claim to be a professional but only a person who wants to learn and this forum is so helpful and patient.

Thanks. Mike P

[Alan in AZ]

Originally Posted by Mpierick

is it a problem if I am only getting 10.4v at the high pressure switch?

Thanks for all your help.

Mike P

10.4v should be sufficient (assuming the pressure switch is conducting).If its 10.4v into no load (insufficient pressure - meaning switch is open circuit) then it could be a problem.

Need to know the voltage when its actually driving the clutch coil...? without the load its impossible to say from the results how it will perform with a load...

Alan

[Danglerb]

Originally Posted by Alan in AZ

10.4v should be sufficient (assuming the pressure switch is conducting).If its 10.4v into no load (insufficient pressure - meaning switch is open circuit) then it could be a problem.

Need to know the voltage when its actually driving the clutch coil...? without the load its impossible to say from the results how it will perform with a load...

Alan

Unless you have a set of LoadPro test leads.