Author |
Message |
Abscate Samba Member
Joined: October 05, 2014 Posts: 22665 Location: NYC/Upstate/ROW
|
Posted: Sat Sep 18, 2021 5:22 am Post subject: Re: DIY - Red Tek conversion |
|
|
You can use compressed air to leak test, you just have to pump down for. A few hours to bring moisture levels down. Most of us don’t have access to N2 at 160psi
If your compressor only hits 100 psi use that _________________ .ssS! |
|
Back to top |
|
|
djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32625 Location: Reading Pennsylvania
|
Posted: Sat Sep 18, 2021 5:41 am Post subject: Re: DIY - Red Tek conversion |
|
|
Watching this ^^^ with interest.
We have another member here running a Subaru who is struggling to get a good temperature drop.
He has done everything outlined in the rebuild threads.
New hoses
New condensor
New Rec/Drier
PAG oil
RedTek
A new genuine VW H style expansion Valve (a twin to the one I installed)
Flushed Evaporator, etc,
He was using and older Subaru compressor but a month ago put on a brand compressor ..... bug bucks!
In short everything that I have done to both my 86 and 90 except for the compressor brand. I have passengers wrapped up in sweatshirts and blankets!
He is rolling his windows down to move some 90° humid air!
We wondered about compressor capacity, we determined that the Subaru compressor pretty much matches the Sanden 507 (early 86 and earlier) on pumping capacity.
He has very high high pressure numbers with a decent low pressure number.
Nothing he has tried remedies this and gives good cooling.
I've questioned if the condensor is properly install, it seems to not be dropping the heat.
Talk about frustration!
Other Subaru conversions are putting out freezing air.... not his.
There is an answer eluding us on this one.
Dave _________________ Stop Dead Photo Links how to post photos
Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473
Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537
Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert |
|
Back to top |
|
|
JudoJeff Samba Member
Joined: May 24, 2013 Posts: 1179 Location: Near Springfield, MA
|
Posted: Sat Sep 18, 2021 6:18 am Post subject: Re: DIY - Red Tek conversion |
|
|
H valve not working or a plug somewhere in the system.
If H valve was even partially working he would have some cooling.
Everything else is new and I assume connected correctly. Many of those valves are defective now right out of the box. Older ones are better. _________________ ________________________________________
1989 Vanagon GL Westfalia Camper, Burned up on 7/31/16.
1987 Vanagon GL Westfalia Camper, Bostig & Rebuilt, sold
1986 Vanagon GL Westfalia Camper, Bostig Sold May 10, 2021
1999 Ford GTRV Westfalia camper (30% bigger Westy layout) |
|
Back to top |
|
|
djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32625 Location: Reading Pennsylvania
|
Posted: Sat Sep 18, 2021 7:02 am Post subject: Re: DIY - Red Tek conversion |
|
|
JudoJeff wrote: |
H valve not working or a plug somewhere in the system.
If H valve was even partially working he would have some cooling.
Everything else is new and I assume connected correctly. Many of those valves are defective now right out of the box. Older ones are better. |
I agree about defective new aftermarket expansion Valves.
We are talking NOS genuine VW.
I found two.
One went in his Van (with no change in performance) and one went in my 90 with excellent results.
They were/are identical to my original 90 valve. After market ones vary from the originals.
It makes some cold, just not adequate.
Both RedTek and r134a have been used with little if any performance change.
The high high pressure with poor output has been a constant.
Dave _________________ Stop Dead Photo Links how to post photos
Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473
Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537
Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert |
|
Back to top |
|
|
mattmoox Samba Member
Joined: September 15, 2021 Posts: 3
|
Posted: Sat Sep 18, 2021 8:36 am Post subject: Re: DIY - Red Tek conversion |
|
|
Thanks for the suggestion on aftermarket H valve. When I originally replaced all my AC system, I took the advice in the original thread and replaced the H valve too. I have a horrible feeling that I threw out the old one (which was working well with R12....grrr), but will have a rummage today and see if I still have it.
Anyone got a recommendation on where to buy a working H valve?
Here's the one I have at the moment:
https://www.partsgeek.com/review-product/0Y15Z1R942L/7340-01369372/
And some questions on H valves -
Is there a way to test the H valve out of the van to confirm it works? As I mentioned before, I did already strip down my current H valve - removed the brass plug and checked that the spring valve moves freely. All good.
Is there a way to test that the H valve diaphragm moves as expected?
Is there a method to calibrate the pressure on the H valve spring (i.e. the how far the brass plug is screwed in)?
Kind of annoying that a $30 part is (perhaps?) the one thing that let's down a $1000 overhaul!
I am encouraged however by all these reports of needing to buy a sweatshirt when this thing is done
Cheers all. |
|
Back to top |
|
|
JudoJeff Samba Member
Joined: May 24, 2013 Posts: 1179 Location: Near Springfield, MA
|
Posted: Sat Sep 18, 2021 8:55 am Post subject: Re: DIY - Red Tek conversion |
|
|
Hi,
I answered this off top of my head. After Dave’s nice reply, I researched it. Assuming everything is connected properly, and working the experts said:
1. Overcharge of refrigerant or oil
2. Blockage in the system
My A/C notes went to the buyer of my Westfalia, sorry I can’t be of more help. _________________ ________________________________________
1989 Vanagon GL Westfalia Camper, Burned up on 7/31/16.
1987 Vanagon GL Westfalia Camper, Bostig & Rebuilt, sold
1986 Vanagon GL Westfalia Camper, Bostig Sold May 10, 2021
1999 Ford GTRV Westfalia camper (30% bigger Westy layout) |
|
Back to top |
|
|
djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32625 Location: Reading Pennsylvania
|
Posted: Sun Sep 19, 2021 5:51 am Post subject: Re: DIY - Red Tek conversion |
|
|
I know of no way to test the H style expansion valve.
I do know that the older L style with the temp probe can be adjusted but haven’t ever done so.
The gentleman I purchased my 86 Westy from was horrified when I told him I replaced the expansion valve.
He was an old HVAC technician and had put many hours into adjusting that old style L valve to produce maximum cooling.
After my after market one didn’t work I reinstalled his adjusted one with excellent results.
It is still working today on the West Coast.
Like Jeff says, I too have stumbled upon the concept of too much PAG being a reason for poor cooling performance.
The thought of disassembling and cleaning out the entire system to KNOW your PAG level is daunting!
And to do this without knowing if is the problem or not?
It could be an action of futility.
This particular Subaru powered system has already been confirmed to NOT have any blockages in the system.
Honestly we are down to pulling our Hair out!
The high high pressure indicates the gas is not dropping its heat in the Condensor or an expansion valve issue. I feel the expansion valve has been ruled out by installing the NOS VW Valve in the VW box.
Why then isn’t the gas dropping the heat?
Undersized Condensor ?
Poor gas flow in the system as a whole, in the Condensor specifically?
Poor air flow through the Condensor?
Incorrect gas flow direction in the Condensor?
Too much PAG gumming up the gas flow or effectiveness of the gas?
You don’t want to just randomly drop some PAG out of the system not knowing if the quantity left is adequate for safe operation.
The selection of poor performance possibilities is growing increasingly smaller with each try at a repair.
I’ve even brainstormed multiple times on the phone (most recently yesterday afternoon) about this problem vehicle with one very well versed in Vanagon A/C operation and RedTek in particular.
He too is now stumped.
I’m thinking a good Winter project for the owner will be to drop the evaporator, disconnect hoses and components and flush them all out.
Refill with a known proper quantity of PAG in each component and try it.
An overfill is quite possible on this rig for over time suspected components have been replaced and new bits have been installed with the suggested by VW Vanagon Oil capacities.
There is absolutely no way to know how much oil is in the system, even after flushing it clean, it will be an unknown quantity that comes out with the flushing agent.
Dave _________________ Stop Dead Photo Links how to post photos
Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473
Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537
Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert |
|
Back to top |
|
|
Farf Samba Member
Joined: July 12, 2009 Posts: 463 Location: Colorado
|
Posted: Sun Sep 19, 2021 9:19 am Post subject: Re: DIY - Red Tek conversion |
|
|
mattmoox wrote: |
After charging the system to capacity (3 cans of RedTek), low/high pressures were:
- Static = 80/80
- Idle = 50/180
- 1500 rpm = 45/195
|
Old compressor compression ratio @ 45/195:
(195+14.7) / (45+14.7) = 3.51
Not too bad, shows old compressor was pumping well. You added 3 full cans of RedTek (18oz.) With the micro channel condenser, charge is critical, a 3 oz. overcharge could easily affect system pressures and operation.
mattmoox wrote: |
I only had around 3/4 of a can of Red Tek left, so I sucked it in as a liquid under vacuum. The static pressure was around 35, and when the compressor kicks in, the low pressure reading was pulling down to around 25
|
I suspect your "rebuilt" compressor isn't pumping well. You should have had a much lower suction pressure with such a low charge.
I wouldn't use your new batch of RedTek on your rebuilt compressor.
You might be able to spray "Dust Off" cleaner onto the bulb inside the H block TXV to see if the needle moves. Doesn't mean the valve is good though. Adjusting superheat (spring adjustment) is probably something you don't want to mess with. I'd put a new valve in.
The new condenser has a much smaller internal volume than the original. An oil overcharge (using Bentley amounts) is certainly possible, but don't know for sure. |
|
Back to top |
|
|
dan macmillan Samba Member
Joined: October 19, 2003 Posts: 3110 Location: Northern Ontario, Canada
|
Posted: Sun Sep 19, 2021 5:53 pm Post subject: Re: DIY - Red Tek conversion |
|
|
What are your pressures at. What is your superheat value. _________________ Licensed Automotive Service Technician
Licensed Truck and Coach Technician
Licensed Heavy Duty Equipment Technician
CFC/HCFC/HFC A/C handling and installation license
Alignment specialist
66 Modified Manx,68 Kyote,74 Thing,74 Beetle, 76 Transporter,75 self made Double Cab,65 Meyers Manx,78Westy,68 Ghia, 79 Bradley GT2
Current projects:
Built for others:69 Manx Clone |
|
Back to top |
|
|
Farf Samba Member
Joined: July 12, 2009 Posts: 463 Location: Colorado
|
Posted: Sun Sep 19, 2021 7:49 pm Post subject: Re: DIY - Red Tek conversion |
|
|
Superheat? Subcooling? Sanden system service chart below with a link to an inexpensive thermocouple thermometer. This has been mentioned in the past, no takers yet. Note, I added the evaporator outlet temp. line.
https://www.amazon.com/Stainless-Thermocouple-Ther...mp;sr=8-24 |
|
Back to top |
|
|
djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32625 Location: Reading Pennsylvania
|
|
Back to top |
|
|
djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32625 Location: Reading Pennsylvania
|
|
Back to top |
|
|
Abscate Samba Member
Joined: October 05, 2014 Posts: 22665 Location: NYC/Upstate/ROW
|
Posted: Mon Sep 20, 2021 4:37 am Post subject: Re: DIY - Red Tek conversion |
|
|
I’ve never used HC based refrigerants like Redtek but my understanding is the high side head is about 1-2 that if R134A
If the Subaru guy has high head pressure relative to R134A numbers, he is either massively clogged or has residual R134A , or both _________________ .ssS! |
|
Back to top |
|
|
djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32625 Location: Reading Pennsylvania
|
|
Back to top |
|
|
Abscate Samba Member
Joined: October 05, 2014 Posts: 22665 Location: NYC/Upstate/ROW
|
Posted: Mon Sep 20, 2021 6:09 am Post subject: Re: DIY - Red Tek conversion |
|
|
High pressure redtek about 1/2 of R134A , correct _________________ .ssS! |
|
Back to top |
|
|
pdm777 Samba Member
Joined: August 06, 2012 Posts: 348 Location: Clovis, CA
|
Posted: Tue Sep 21, 2021 2:02 pm Post subject: Re: DIY - Red Tek conversion |
|
|
I say, start with a clean slate.
We have No Idea what the prior owners have put
into the AC system. Stop Leak/Dye/Oil etc.
Most 'refill' kits have stop leak, yellow dye, and Oil.
You will end up with compromised cooling when there
is an excess amount of these additives.
I flushed at the dryer fitting (always replace the dryer) with a funnel
to get 2-3 cups of Menthanol into the lines, and then blow it through the lines with compressed air and out to a bucket. Rinse and Repeat.
Filthy, Ugly Snot will come out of the lines !!!
Keep flushing until the solvent is clear, then blow out
the lines with compressed air for 30-60 minutes.
Your AC System is now as Clean as New.
Take the compressor off and fill with solvent,
rotate the moving parts and get all of the Old Oil out.
Refill with New oil, New refrigerant.
I prefer Red Tek or EnviroSafe, they have much less high side pressure
and mimic the original R12 without the environmental concerns. _________________ 1990 Westy Full Camper |
|
Back to top |
|
|
|