AC question

[Cougsfan]

It is a 2017, It has the low ceiling, right before they made it higher.
I didn't tear them apart, but I think the block valves are just bulkhead fittings. They don't restrict flow in either direction.
I will work on your other two items. In fact I will take several pictures.

 

[LouNY]

I have a service manual for a NH T6050 it has a very good trouble shooting section for the AC.
I will try and attach it.
View attachment NH AC troubleshooting C.pdf View attachment NH AC troubleshooting B.pdf View attachment NH AC troubleshooting A.pdf
Well that was a royal pain with a 10mb file limit I had to break it down into sections A,B, and C
It may help, I certainly hope so

Good Luck

 

[Cougsfan]

Here are some pictures:
First, where the service manual shows the receiver dryer:

This is what mine looks like. Not at all like they show. As I said, if you follow the line out of the condenser all the way to the expansion valve, no receiver dryer.

This is the new receiver dryer (still in the bag as I may have to return it) and the old expansion valve (My guess is there is nothing wrong with it.)

This shows the evaporator and newly installed expansion valve under the roof. I took the ducts out of the condenser off to remove the lid on the evaporator and haven't put them back on yet. I also need to re-insulate the expansion valve. I'm going to cut up some sponges and tape them around the valve (if I ever get things working). That sticky, rubbery tar the factory put on for insulation is the pits!



As a note, after setting 6 hours with a vacuum, the system did loose just a bit of the vacuum. So it is either moisture evaporating (hopefully) or a leaky quick disconnect on the vacuum pump hose connection (more likely).

 

[Cougsfan]

The picture in the manual shows a electrical connection on the receiver/dryer. What would that be for?

Also thanks for the manual, Lou. I will read through it. I can't believe how much I have learned about automotive style ac systems in the last couple weeks (unfortunately, I haven't yet learned enough.)

 

[LouNY]

On the pdf I attached on page 7 the New Hollands have "self sealing quick connects" I wonder if the Branson QC's you found are similar if so is it possible that some particles got into one of them from your failed hose.

 

[K5lwq]

The picture in the manual shows a electrical connection on the receiver/dryer. What would that be for?

Also thanks for the manual, Lou. I will read through it. I can't believe how much I have learned about automotive style ac systems in the last couple weeks (unfortunately, I haven't yet learned enough.)

That plug is most likely for a low pressure switch. You are doing a great job of working this problem. You will find a solution no doubt!

 

[Cougsfan]

Lou, it is probably the same self sealing quick disconnect. It is one that is standard for automotive type systems. It is very much like a standard air hose quick disconnect except it has a rubber seal at the base of the female fitting. My friend says that in his experience they hold quite well but sometimes seep if held under vacuum for a long period of time. Probably from specs of dirt on the seal. He prefers the old threaded connections that are no longer used.

He has a set-up for flushing the system with some type of solvent made for refrigeration systems. He uses it when a compressor or a dryer fails. My oil is still quite clear so I am not sure we need to use it. No contaminates came out when we blew air through the lines.

 

[Cougsfan]

Lou, I was reading through that PDF and found the "self sealing quick disconnects" you were talking about on page 7. Those look identical to the "Block valves" in the Branson we have been talking about and they are at similar points in the system. They don't look much like "quick disconnects" though 'cause it takes a handful of different wrenches to disconnect them.

 

[TractorGuy]

I would try putting a big fan in front of the condenser and attempt to get the prescribed charge in the system.

 

[Texasmark]

This great nation was founded by people who didn't know what they were doing, and it grew mighty with the help of many more such people. We're scolded for it, but it's our indomitable, independent spirit coming through.

In looking at page K25W-201504 of the 20 series service manual which applies to the 4720, the "block valves" look like they're just bulkhead fittings, not valves. Here's a picture of the diagram to help envision the schematic of the pattern, and I've colored the "valves" red. The expansion valve is on the evaporator, and I've colored it blue:

View attachment 664925

My take on "block valves" is this: At some point in the assembly process the cab is married to the tractor chassis. The AC system components in the roof , aka evaporator and expansion valve can be filled with freon and checked for functionality including possibly the setting of the expansion valve release pressures. Meanwhile the tractor chassis can be filled and operated, checking functions on it's assy line ready to mate with the cab.

Both assemblies could have blocking valves incorporated in their interconnecting hose connectors to retain any refrigerant/oil that may be a result of production line testing, and to prevent proper processing and filling of the AC at final assy.

On the side of my engine my lines meet and one is supported by a clamp to hold it in place. I am assuming that the cab it placed on the chassis and interconnections are completed. For the AC system, it's a matter of mating the two connections and the AC system is ready for shipment.

You can buy pre charged lines for home AC systems that perform the same function.