Installing Aftermarket AC in a Dodge Van

[GottaBeCold88]

Ok. I’ll make sure it’s properly wrapped up.

A while back, before I starting talking to you guys, I had a wild idea to hole a flame up to the sensing bulb to see if it would trick the TXV to flowing more refrigerant and making the evap blow colder. It didn’t work. In fact I don’t think it changed the temp at all.

Okay I’ll get it recovered tomorrow and adjust the TXV as soon as possible.

[tbirdtbird]

Hope it didn't get too hot. We use hot water on a rag. Was prolly already opened as far as it could at that particular screw setting

[GottaBeCold88]

Ok. I did it. Turned the screw out (ccw) one full turn. Will charge and report back… thanks

[tbirdtbird]

Good.
Can we assume there was still some spring tension on the screw....

You didn't know that little bugger was hiding in there I bet...

[GottaBeCold88]

Yep there was still tension. and no I didn’t know that little bad boy even existed. The source of all my troubles. Too bad they don’t make them accessible from the outside!

Well tonight in 79* weather, 45% humidity I got 27oz in before running out of Freon. Still need to add another 10oz when I go to the store, but the temp got down to 48-50 at the vent which is the coldest yet, so I’m excited. Can’t wait to see what it does with a full charge! Wahoo!

[tbirdtbird]

Wahoo! is right on!
Keep us posted
nice work

I'm sure Detroit will be pleased

[GottaBeCold88]

Ok, I'm back fellas. And, slightly disappointed I'm afraid.

Last night's 50F vent temps were nowhere to be found. Today, at estimated full charge, coldest I got was 60*.

Granted, today was warmer than last night, 84F with 45% humidity.

Filled up to 36.6oz (all I could get out of my last can was a little less than 10oz) so just 0.4oz shy of my original charge before I adjusted the TXV. With me TXV adjusted, my numbers are now better, but still only a 60* vent temp at full load, windows open, 1500rpm, etc.

Check out my updated chart below:



According to my calculations, I'm at 20* Subcool, at 32* Superheat.

(By the way, you'll see two numbers in the low pipe temp column, as I was asked to measure both pipes coming out of the evap. They were very close to each other, but the #10 was 1-2 degrees cooler than the smaller one)

So, if turning the TXV screw out 1 turn lowered my superheat from 38 to 32, that's 6 degrees. To get down to around 10, I need to lower superheat by 22 more degrees. If one turn got me 6 degrees, I need to turn it out another 3.66 turns, making 4.66 turns total from how I received the TXV.

Does my logic check out? And, will the screw even turn out that far without falling out of the housing?

[DetroitAC]

Man, this makes no sense, something is wrong.

When you say you are measuring the pipes coming out of the evaporator, do you mean the inlet pipe (going from TXV to evap) and the outlet pipe (going from evap outlet, has bulb attached, goes to the compressor)?

When you calculate suction superheat are you taking the pressure at the service port and the temperature at the service port?

If those in/out pipe temperatures are to be believed (do they feel like they are in the 70s with your fingers?), your suction line pressure drop is what's killing you.

Also, how much oil do you have in there?

[GottaBeCold88]

Re: the evap, yes. There are two short hard metal lines with fitting on the ends, one attached to the TXV the other to the #10 hose (low side) which goes down the a pillar and through the firewall to the service port and then the compressor.

The other temp is measured at the outlet on the condenser (bottom). The line then goes to the drier, and then to the service port. So there is a drier and about 18” of hose between the area where I’m reading temp and the service port.

Can I try adjust the TXV more?

I’m also putting in a bigger fan, for what it’s worth.

As far as oil, after I got it recovered two times ago, I removed the compressor and drained it and refilled it with 4.5oz of oil. When I drained it, it only had .5oz.

[DetroitAC]

OK, but you measured those temps where I'm pointing in this picture, correct? 76F after the TXV, before the evaporator? Please confirm

I don't think adjusting the TXV was good advice based on this,