A question about dash A/C replacement.....
75 degree air was coming out of the vents. It was 85 deg outside and on max cool. A mobile tech came to visit and even after adding l lb. of R134a......no improvement. He went under the coach and f...
Forum Discussion
If you don't know what gauge readings the mobile tech got, there's no way to guess what might be wrong.
He DID connect what they call a Manifold Gauge Set, didn't he? A head with two gauges, a couple valves, and long hoses to connect to Suction/Low Side, Discharge/High Side, and the Refrigerant Supply? All A/C systems require an Expansion Device, which is where the Discharged refrigerant expands to absorb heat. GM and Ford used to always use an Orifice Tube. The heart of it was a little brass tube like a piece of ballpoint pen refill. It had a screen that could get clogged but beyond that didn't actually fail. Imports and Chrysler typically used a Thermostatic Expansion Valve (TXV). Those CAN fail (they stick) and no cooling. If that happens it needs a Valve and not a Compressor. I think you need a better diagnosis.
EDIT - Above assumes the Workhorse Chassis included the A/C. I'm not current on that but I recall that the chassis used to NOT include what's correctly called HVAC (Heating Ventilation Air Conditioning) and various aftermarket suppliers provided it. Frigette, also known as SCS/Frigette, was one but I think they went out of business, Evans TempCon another, and I'm sure there were more. That made it difficult to get service information and parts. Still, I think at least most of them used TXV, not Orifice Tube.
To answer your question:
If replacing Compressor, YES, change out the Expansion Device AND the Drier. You said "X-Valve" which is the same idea as TXV.
Come to think of it, if you can find the "Drier" and it's in one of the SMALL diameter lines, probably close to the Radiator and A/C Condenser, then you have X-Valve/TXV and the Drier is called Receiver-Drier. If it has Orifice Tube, you'll find a much larger (coffee can size) Drier and it'll be in the larger diameter lines and probably away from the Condenser. Usually called Accumulator, but it has the dessicant inside so it's in practicality an Accumulator-Drier. Best practice is to seal the ends of the open lines when the A/C is apart, then install a new "Drier" (whichever kind the system call for) then evacuate the system with a vacuum pump before recharging with refrigerant. Once the Drier's absorbed moisture, evacuation won't make the dessicant useful again. Evacuation will evaporate only moisture that got in while working. Moisture interferes with cooling, and it also reacts with refrigerant to create acid and corrosion inside the system.
He DID connect what they call a Manifold Gauge Set, didn't he? A head with two gauges, a couple valves, and long hoses to connect to Suction/Low Side, Discharge/High Side, and the Refrigerant Supply? All A/C systems require an Expansion Device, which is where the Discharged refrigerant expands to absorb heat. GM and Ford used to always use an Orifice Tube. The heart of it was a little brass tube like a piece of ballpoint pen refill. It had a screen that could get clogged but beyond that didn't actually fail. Imports and Chrysler typically used a Thermostatic Expansion Valve (TXV). Those CAN fail (they stick) and no cooling. If that happens it needs a Valve and not a Compressor. I think you need a better diagnosis.
EDIT - Above assumes the Workhorse Chassis included the A/C. I'm not current on that but I recall that the chassis used to NOT include what's correctly called HVAC (Heating Ventilation Air Conditioning) and various aftermarket suppliers provided it. Frigette, also known as SCS/Frigette, was one but I think they went out of business, Evans TempCon another, and I'm sure there were more. That made it difficult to get service information and parts. Still, I think at least most of them used TXV, not Orifice Tube.
To answer your question:
If replacing Compressor, YES, change out the Expansion Device AND the Drier. You said "X-Valve" which is the same idea as TXV.
Come to think of it, if you can find the "Drier" and it's in one of the SMALL diameter lines, probably close to the Radiator and A/C Condenser, then you have X-Valve/TXV and the Drier is called Receiver-Drier. If it has Orifice Tube, you'll find a much larger (coffee can size) Drier and it'll be in the larger diameter lines and probably away from the Condenser. Usually called Accumulator, but it has the dessicant inside so it's in practicality an Accumulator-Drier. Best practice is to seal the ends of the open lines when the A/C is apart, then install a new "Drier" (whichever kind the system call for) then evacuate the system with a vacuum pump before recharging with refrigerant. Once the Drier's absorbed moisture, evacuation won't make the dessicant useful again. Evacuation will evaporate only moisture that got in while working. Moisture interferes with cooling, and it also reacts with refrigerant to create acid and corrosion inside the system.
