Automotive Air Conditioning Information Forum

The big question:
Will a drier negatively affect an FOT system? As in having one between the condenser and the orifice tube.


The details:
I'm working on getting the AC in a '74 Chevy C10 going.

I'm using the original evaporator/heater box. The evaporator has a fixed orifice tube.

I went for Vintage Air's condenser kit.
The kit comes with pre-bent lines, brackets and a drier. I know the drier's redundant when there's going to be an accumulator full of desiccant after the evaporator using the FOT.

At this point, if I can just plumb in the drier without causing any issues, that's the easiest solution. Otherwise, I need to bend a new line, or get a fitting to "delete" the drier.

Other thoughts:
Another reason I picked the VA condenser kit (and its drier) in the first place is I thought I might switch the system to a TXV. I'd need to modify the evaporator and I'm concerned about liquid ending up in the compressor without an accumulator if I don't pick the right TXV.
It would be a cleaner install (if I'm confident enough to not use an accumulator), but is a TXV so much better than a FOT to justify all that?

Other info:
The truck has a serpentine setup from an '88 Camaro. So there is an R4 compressor on the passenger side as opposed to an A6 compressor on the driver side. I'm replacing the Camaro's R4 with a Sanden.

Thanks!

I do not believe this would be a problem. Both are often used on commercial refrigeration applications. In fact, my commercial ice cream truck has both.
For the record, a TXV by mere definition of the way it works will not spill liquid refrigerant into the low side line, like an OT, which is why they do not require an accumulator.
You did not mention what section of the country you live. For the record a TXV will outperform an OT any day of the week, but I am sure you will be OK.
Be glad that you are replacing the R4 with a Sanden.

- I'm in North Alabama.


- So, about the TXV conversion. I was looking at several on Summit. Figured I'd pick one that had just the right length capillary tube for a tidy install. Then I looked up the specs on the various ones I was considering and saw they had different superheat values.

This led me down a rabbit hole.

As I (a layman currently) understand it, the lower the superheat value, the more liquid the TXV will allow into the evap.

So, if I played it safe a pick a high value, I'll leave performance on the table. And if I pick too low of a value, I'll risk slugging the compressor.

I could be waaay off and worried about nothing.
Edit: Re-reading the post I'm responding to, I must be way off.


- Yeah, it didn't take much research to convince me to ditch the R4. Not too popular.


Thanks!

I am surprised they showed any superheat values at all. Mobile AC does not care about superheat or subcooling, because the compressor and rest of the system is so variable.
Most of the TXVs are 1 ton. A few are 1.5 ton. Not usually a concern. It is very hard to determine what the tonnage rating is. Last year I was able to find a chart and learned that the vast majority are 1 ton. Some 1.5 ton. Never saw any 2 ton. I am using a 1 ton in a big'ol 1959 Cadillac boat of a car and it works fine.
If there is a high load on the evap, that TXV will open all the way up and give you all the freon you want. It compares the inlet of the evap to the outlet and regulates from there. The sensing bulb must be tight to the outlet tube and well insulated
Length of cap tube is irrelevant.

TLDR:
I'll probably go with the Vintage Air TXV. I could have sworn I started looking at other TXVs to find a shorter capillary tube thinking the VA TXV had a super long one. But I guess I was just looking for cheaper options. It's at least twice as much as most others, but I s'pose it does come with the insulative tape.

Edit: Removed section related to external links.

Of course, the Vintage Air TXV is a mystery. I would email them, but they have this in red on their contact us page:
"Please Note: Vintage Air, Inc. does not provide replacement parts, repair information, or retrofit data for Factory-installed or Original Equipment (OE) Air Conditioning systems."
Guess it doesn't hurt to ask.

Wondering about this thread.

Me too.
It is all over the place. I did not think you allowed links to off site sales, either.
And since when would the cap tube be in the engine compartment

Yeah, the threads original question has been answered. So I guess I'm good.

Removing the links.

A '74 Chevy C10 has the entire evaporator hanging off the firewall on the engine side. Everything's as exposed as it possibly can be.

Good luck then

Modify your evap if you want to use an Exp Valve. 1.0 or 1.5-ton valve should be used. All custom work, but can be done.