Finally got my A/C working(PIC'S)

[BobbyK]

Well I had rebuilt my A/C and heating system about 5 months ago but never got around to getting the A/C working.

I got er done last week though.

I retro'd the system from R12 to R134a and got rid of the POA valve.
I used a POA eliminator from Old Air Products.Along with a fixed orafice tube(FOT) and a pressure cutout switch.

The system cools O.K.,still some fine tuneing needed but I get about 50F at the vents.Not bad but I'd like it colder.

Here's a few pic's of the process.

This is the connection to the low pressure side of the system.That's the POA eliminator I had mentioned earlier.An integral pressure cutout switch comes with the POA eliminator.
I just spliced into the existing A/C compressor wire.What it does is it shuts down the compressor and prevents the evap. from feezeing up.


Here is the high side connection at the compressor.I used a Sanden SD5H14 compressor.


I used is a RobinAir,1/2hp,6cfm vacume pump to evacuate the system before charging.


The gauge set I used.This allows you to measure the vacume you pull on the system as well as the pressure in the system while chargeing it.
In this pic I'm evacuating the system.The gauges are at -29.5inHg,which is as far as you can go on the planet Earth.


The can tap I used.I ended up overcharging the system a bit.I used four(4),12oz cans of R134a to charge it up.


Killin time while evacuateing the system


I connected my can tap to my vacume pump via an adaptor I bought at Car Quest.This way I can eliminate the chance of air getting in the system when I have to change cans during the charging process.


I had to "jump" the cutout switch during the first bit of charging.The compressor would not engage untill some pressure was in the system.
[image]http://images6.fotki.com/v94/photos/2/229137/865118/DSCN0991-vi.jpg[/img]

Just an overhead view of things.


This is the top tube of the evaporator core.Condensing like it should,cool to the touch but not iceing up.


And the bottom line.The line on the right is the FOT.It meters the amount of r134a that got through the evap. core.It function like the TVX valve on the old POA system.


Like I said I still nedd to "tune" it a bit.Might need to put in a smaller FOT or take out a bit of R134a.Worst case would be a new parallel flow condensor.I have the orig. type in there now.Through the reading I've done the orig. condensor design may not work that well when retro'd to R134a.

[Yukon Jack]

50F sounds pretty good, what is generally considered a normal temp?

[Gee_Emm]

Cool, although I did open this thread expecting to see icicles hanging from your rear view mirror so I am a little dissapointed.

Does anybody down there get the lisence plate?

[BobbyK]

Very few.
Most think it means something like "Hikeing" .Most just stare at it with a blank or puzzled look on thier face.

Cool, although I did open this thread expecting to see icicles hanging from your rear view mirror so I am a little dissapointed.

Well I'm hoping to get it that cold,in the 40's at LEAST.We'll see today after I take it for a drive.
I'll post updates.

[cheyenne10]

OK, let here good explaination

Is that a sidewinder winch behind the plate?

[BobbyK]

Nope,just a reg. old Warn 9000.

OK, let here good explaination

HKYISLIF=HocKeY IS LIFe

[red71cheyenne]

Nice post Bobby. How much does the vacuum pump hold when you evacuate? Do you just discard the old refrigerant after that? Did you have to change out all the seals and all for the 134 as well? Wish I could get all my pulleys to line up as nice as yours do. Jeff.

[BobbyK]

The vacume pump is not used to pump out old refridgerant.
By law,you must reclaim what's in your system and then use the vacume pump to evacuate all the air out of the system.The vacumeing proceedure will boil off any moisture in the system as well.

Well the only thing I had that was from the orig. A/C system was the evaperator and the POA valve,The rest of it had been removed by the P/O.
So really everything was replaced with R134a compatable parts.
I installed:
-new hard and soft lines
-new compressor
-new condensor(not a parallel flow design)
-POA eliminator
-new receiver/dryer with R134a disadent(spelling)

I evacuated the empty system with my vacume pump.Pulled vacume for 30 min X2 with a 15 min break in between.The vacume held during those breaks so I knew the system didn't have any leaks.

I then charged the system with the 12oz. cans of freon you get at any parts store.

It cools ok with vent temps in the 50's but that's not good enough.I think an A/C system should at LEAST get into the 40's to cool the vehicle cabin off on a hot day.

I took it for a spin today with no better results than I had with it stationary in my driveway.
I even watered down the condensor to see what that would do.Other than decreasing head presures it didn't make the vent temps cooler.

I think I might try a smaller FOT(fixed orafice tube) and see what happens.

[red71cheyenne]

Hmm. Ok, I thought the vacuum was to pull all the old refrigerant out. Don't know much about the systems though. When I had mine serviced a few years ago I just kept the R12. I guess you can still get it if you need it. Its expensive though. Mine does not get very cold either, but the A/C guy said its because the damper does not shut off the hot air very well. Do you know if our system is designed to run the compressor while its on defrost like the new sysytems?

[BobbyK]

Do you know if our system is designed to run the compressor while its on defrost like the new sysytems?

I'll have to check that.

I know the compressor will only come on if the fan is on(any speed).
I think the lever must at least be set in a position that will depress the A/C clutch switch which is located on the back of the inside ducting.
That's the switch here on this inside duct.

[red71cheyenne]

I think that given the way ours is set up it won't run the compressor on defrost. When you put the lever on defrost, it pulls the A/C lever that way, off the switch. Guess you could make it work though, if you reworked the way the levers contact the switch.

[BobbyK]

Anything is possible man!

[red71cheyenne]

True. Think I will rework mine anyway. The plenum you have in the pic doesn't mount up very well in my truck. May just be worn out from all the in and out over the years. I know the baffles in there don't work as well as they should, especially when it comes to switching between modes of operation. May just have to upgrade it all. Later, Jeff.

[BobbyK]

Well...good news
Today I added 6oz. of R134a for a total of 36oz in the system.Had some good results with this change.

Here's the data as of today(7/22/04)

At about 1700rpm
low=25
high=peaked at 260
vent temp-44-46F
ambiant temp lower today=75F.
fan on high
Compressor cycled,on for 30sec,off for 5sec.

at Idle(approx.700rpm)
low=30-38
high=180-230
vent temp=44-46F.
fan on high
Compressor DID NOT cycle.

Here's the kicker.
I turned the interior fan on low and my vent temps dropped even more.

at idle
low=30
high=180
vent temp=38-40F.!!!!
Compressor DID NOT cycle.

At 1700 rpm
low=25
high=200-220
vent temp=42-43F.
Compressor cycled,on 30 sec,off 5sec.

So I'm pretty happy with those vent temps.

Thanks to those that made suggestions.

Hope this info. can help others down the line.

[ericguy320]

the slower the air moves through the evap core the more chance it has to exchange the heat. those numbers look good, it wouldnt hurt to turn down the low preasure cycle switch to cut off at around 17-20 insted of 25psi