AC Conundrum

[Butch65]

Gents,

I have come upon a curious problem and I'm hoping someone out there will have the obvious answer that I am overlooking.

Here's the situation:

Rebuilt the heater / AC box a year ago ( Classic Auto Air Kit). Everything new inside, all gates refurbed and working smoothly.

Installed CAA's under hood upgrade kit last weekend. (Sanden compressor, new hoses,condenser,receiver, expansion valve.)

System is charged as reco'd ( done by my local shop).

I double checked all vacuum lines and actuators for proper connections and leakage- system holds 22" of vacuum ( using hand vacuum pump). All good there.

I have the water valve vacuum motor forced open to help with troubleshooting (no hot water).

The Clutch is engaging and the Expansion Valve does get cold. Since the compressor is activating, and I have a cold Expansion Valve, I presume that the thermostat switch is operating properly.

I have the glove box out and the center dash panel out, so it's easy to see the actuator movements. Heck, we even labeled all the actuator motors and valves to make following the troubleshooting guide easier! So it appears that everything is working - Slide control arm to Max Air (cable controlled) and the temp blend door opens, and actuators 1,3,4 & 7 all shift.

Fan is worked great - lots of air moving.

IF I have coolant flowing through the EV and IF my actuators are working properly, what am I missing? (other than my ice cold air!)

Thanks on advance for the help.

Butch

 

[basstrix]

We'll need to know what the high and low side pressures are, what type of refrigerant you're running, and what the duct and ambient temperatures are.

I'm not familiar with this kit....what major components does it include?

 

[Butch65]

Thanks for the response.

Components:

Sanden 508 style compressor,new hoses,condenser,receiver, expansion valve. Evaporator coil was changed when the heater box was rebuilt last year.

I recall Hi at 170, low at 20. Running R134

Ambient temp is 77 right now, and the air at the vent is 76.

I just ran it again, and noticed that the compressor is chattering. I'm keeping the engine rpm at 12-1500 while testing.

We'll need to know what the high and low side pressures are, what type of refrigerant you're running, and what the duct and ambient temperatures are.

I'm not familiar with this kit....what major components does it include?

 

[kcmash]

Sounds to me like you are low on R134a based on the pressures you gave. You should be closer to 40 psi on the low side from what I see.

View attachment 34639

 

[basstrix]

Thanks for the response.

Components:

Sanden 508 style compressor,new hoses,condenser,receiver, expansion valve. Evaporator coil was changed when the heater box was rebuilt last year.

I recall Hi at 170, low at 20. Running R134

Ambient temp is 77 right now, and the air at the vent is 76.

I just ran it again, and noticed that the compressor is chattering. I'm keeping the engine rpm at 12-1500 while testing.

We'll need to know what the high and low side pressures are, what type of refrigerant you're running, and what the duct and ambient temperatures are.

I'm not familiar with this kit....what major components does it include?

When you say chattering, does it seem as though the clutch is engaging and disengaging in succession? There are both over-pressure and under-pressure switches that can cause this. If you don't know the real time pressures, you'll be shooting in the dark as to what the root cause is.

Here's an example: Let's say that the system was properly charged and pressures were normal at the shop who charged it, but since then, enough refrigerant has leaked out such that the low side pressure is at the threshold of where the low pressure switch opening and closing....due to insufficient refrigerant. On the other hand, let's say you have a faulty low pressure switch but the system is properly charged. Without knowing the low side pressure, you can't tell which it is.

I agree with previous poster, the pressures you recall seem low, but you really need to know what they are, real time.

 

[Butch65]

After checking pressures again, we removed the Expansion valve to find it blocked with fine debris. Cleaned out the valve, blew out the evaporator. Vacuum and recharge and we had cold air. During this operation, we removed the adjustment assembly , and while I think it's back to where it was based on number of turns, is there a prescribed tension for our systems?

Thanks for the response.

Components:

Sanden 508 style compressor,new hoses,condenser,receiver, expansion valve. Evaporator coil was changed when the heater box was rebuilt last year.

I recall Hi at 170, low at 20. Running R134

Ambient temp is 77 right now, and the air at the vent is 76.

I just ran it again, and noticed that the compressor is chattering. I'm keeping the engine rpm at 12-1500 while testing.

We'll need to know what the high and low side pressures are, what type of refrigerant you're running, and what the duct and ambient temperatures are.

I'm not familiar with this kit....what major components does it include?

When you say chattering, does it seem as though the clutch is engaging and disengaging in succession? There are both over-pressure and under-pressure switches that can cause this. If you don't know the real time pressures, you'll be shooting in the dark as to what the root cause is.

Here's an example: Let's say that the system was properly charged and pressures were normal at the shop who charged it, but since then, enough refrigerant has leaked out such that the low side pressure is at the threshold of where the low pressure switch opening and closing....due to insufficient refrigerant. On the other hand, let's say you have a faulty low pressure switch but the system is properly charged. Without knowing the low side pressure, you can't tell which it is.

I agree with previous poster, the pressures you recall seem low, but you really need to know what they are, real time.

 

[Butch65]

After checking pressures again, we removed the Expansion valve to find it blocked with fine debris. Cleaned out the valve, blew out the evaporator. Vacuum and recharge and we had cold air. During this operation, we removed the adjustment assembly , and while I think it's back to where it was based on number of turns, is there a prescribed tension for our systems?

Thanks for the response.

Components:

Sanden 508 style compressor,new hoses,condenser,receiver, expansion valve. Evaporator coil was changed when the heater box was rebuilt last year.

I recall Hi at 170, low at 20. Running R134

Ambient temp is 77 right now, and the air at the vent is 76.

I just ran it again, and noticed that the compressor is chattering. I'm keeping the engine rpm at 12-1500 while testing.

We'll need to know what the high and low side pressures are, what type of refrigerant you're running, and what the duct and ambient temperatures are.

I'm not familiar with this kit....what major components does it include?

When you say chattering, does it seem as though the clutch is engaging and disengaging in succession? There are both over-pressure and under-pressure switches that can cause this. If you don't know the real time pressures, you'll be shooting in the dark as to what the root cause is.

Here's an example: Let's say that the system was properly charged and pressures were normal at the shop who charged it, but since then, enough refrigerant has leaked out such that the low side pressure is at the threshold of where the low pressure switch opening and closing....due to insufficient refrigerant. On the other hand, let's say you have a faulty low pressure switch but the system is properly charged. Without knowing the low side pressure, you can't tell which it is.

I agree with previous poster, the pressures you recall seem low, but you really need to know what they are, real time.

 

[basstrix]

Glad you got the system working again. I don't have any experience with the adjustment assembly.