New HE Owner - 1991 CAT 963 21Z

[rokatx]

This is my first day with that 963 and also my first day on HEF, and I already found some really useful stuff. Thank you to everyone who's active on here and is answering questions and is helping out.
I did purchase new arm rest pads since the old ones are in bad shape and I found a thread here which talked about how to replace those.

But my next fix will have to be the AC and Heater. I couldn't get neither to operate.
Any pointers for what the best course of action is to troubleshoot that would be appreciated.

The machine is close to 18k hours on it, had a engine replacement in 2021. It has some rust, but not terrible. It did spend some time in Canada it looks like, and Pennsylvania as well. I'm guessing that's where that rust is coming from.
It's now located in Central Texas.

When moving, the tracks are very squeaky and I've been told that this could be an indication of dried-up pins.
Rollers, trackpads/grousers look like they are in good shape, sprockets probably could be replaced in a few hundred hours.

I will use this machine on my ranch place for clearing out trees and digging out a pond. I doubt I will put 1000 hours on it and would think that after my work is done, I would sell it again.

Thank you in advance - I'm sure I will be a source of further posts down the road.

 

[Robert Boggs]

Welcome to the forum, it’s certainly a great tool in the arsenal. Good luck with your projects!

For the HVAC system it sounds like you need to start with the blower motor. Does it run at any speed? Voltage/current present if not?

 

[Welder Dave]

Check for power. If none check fuses. If everything looks OK follow the wires looking for damage or bad grounds.

 

[Nige]

Got any manuals yet.? If you are going to maintain it yourself they will be invaluable.

Operation - SEBU5846
Maintenance - SEBU5847
Parts - SEBP1367
Service (should include both Operation & Maintenance) - SENR2280

 

[rokatx]

thank you all - did not notice any function whatsoever of the HVAC. This already helps a bit and I will start on the troubleshooting trail. Not thrilled that all the labeling is in French.

Thank you Nige - I already purchased the manuals based on some posts I found in here. Didn't know there was a parts manual though. Will look into that.

 

[Nige]

I already purchased the manuals based on some posts I found in here.

It's important to base searches for manuals on the exact machine Serial Number.

As there can be breaks in machine production a manual that suits one particular S/N may not suit another S/N (of the same prefix, 21Z in your case) simply because they are on opposite sides of said S/N break. I was looking at a backhoe loader yesterday and discovered 3 different manuals based on that exact thing.

Not thrilled that all the labeling is in French.

Not surprising. It's a French-built machine. Your one was probably built originally for a domestic sale then found itself exported later.

English versions of any label/decal/plate containing text (not pictograph symbols because they are universal) ought to be available. If you look at the bottom RH corner of any particular one you should find a Part Number. That number ought to be sufficient to track down an English-language equivalent of the same decal.

 

[rokatx]

Finally had time to troubleshoot the AC more. Well, maybe the weather in Central Texas has something to do with it too...

Took the seat out, removed the housing around the climate controls. Turned out to be a disconnected cable.

Plugged that back in and the blowers are working again. Condenser fans kicked in too.
Still no cold air though.

I'm only getting 2.5V (green wire) or so to the compressor. Is that normal? Is that supposed to be only some sort of signal voltage or would this have to be 24V?

 

[rokatx]

Could anyone help me identify this thing hanging on the side of what I believe is the Receiver on my condenser unit? Is that some sort of valve or sensor?

I have 24v going into the receiver but very little voltage coming out of it.

I have not been able to check the HVAC pressure yet. Needed to order another set of valve adapters first.

TIA!

 

[Bootheal]

Not familiar but will guess, high pressure switch?

Does it have continuity across the terminals?

Nice looking machine and good looking rootrake.

 

[Dave Neubert]

that is the low pressure switch jump across both wires and see if clutch kicks in

 

[Bootheal]

Is this not the accumulator (receiver)?
If so, that would make it the high side of the system…but again, not familiar with this setup.

 

[rokatx]

It does seem to be the receiver. This is the part number I was able to research:
cat 164-0622

I'm unfamiliar with the function of this thing.
Still trying to troubleshoot the AC and this is where I'm currently at. This switch seems to prevent proper 24v to reach the compressor - I have a few fittings/adapters coming on Saturday that hopefully will allow me to connect by gauge set and see what pressure is on the system.

If I were to go the route of hiring this work out, who would be able to work on this outside of CAT service?

 

[rokatx]

that is the low pressure switch jump across both wires and see if clutch kicks in

I found this:

Low Pressure Switch Male 1/4" - Normally Open (2601278) - AC Parts for Auto, Truck, Off-road, AG, & Farm

Brand New Multi Fit Application Normally Open - Low Pressure Switch 1430, 085108-00 - 2 Terminals ; Close-35psi - Open-25psi

www.acparts.com

Looks like this would be it.
Hoping I can get a read on the pressure tomorrow when I have the right fitting/adapter for the gauge set.

Thank you!!

 

[Bootheal]

Receivers are generally down stream of the condenser. If this is in fact the receiver, that would make it a high pressure switch.

High pressure side starts at the compressor (smaller piping) travels to the condenser, receiver, drier, sight glass (I see you have one) and on to the expansion valve. Everything from the expansion valve back to the compressor, is low pressure side. Usually larger piping.

For what it’s worth.

 

[Dave Neubert]

Is this not the accumulator (receiver)?
If so, that would make it the high side of the system…but again, not familiar with this setup.

Yes but it shuts the clutch off if the pressure is low so you don't burn up the compressor

 

[Bootheal]

I’m sure you are correct.

I realize it is a cost saving decision but I would assume there would have been a low pressure and a high pressure control. Now, I have to go look…

Thanks.

 

[Cliffy]

Yes but it shuts the clutch off if the pressure is low so you don't burn up the compressor

As my trade school teacher would say there are no incorrect answers. Its manufacturer dependent.
Some switches are high/low cut out. Some just low pressure or just high pressure cut out.
Trinary switchs also include a fan control.

 

[Cmark]

That's the dryer. The receiver is here. Item 37.