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dobryan
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Joined: March 24, 2006
Posts: 16501
Location: Brookeville, MD
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AndyBees
Samba Member
Joined: January 31, 2008
Posts: 2328
Location: Southeast Kentucky
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 Posted: Mon Sep 18, 2017 8:34 am Post subject: Re: DIY - Red Tek conversion |
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| Syncro Jael wrote: |
I am pretty satisfied with my last RedTek charge. New condenser, hoses, and previous replaced components. Upper temp gauge is vent temperatures. Plenum has been removed. It took some tweaking to get the pressures where I wanted them.
Link
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Now, that's cool, no pun intended....
My R134a expels air at about 42f max under the same outside ambient conditions as you have depicted. It keeps the inside satisfactorily cool for now. I did replace hoses and do a flush back in August. When it goes south again, I may opt for the Red Tek....
_________________
'84 Vanagon Tin-top, ALH TDI. 1989 Tin-top
1983 Air-cool, 225k miles, 180k miles mine. Seven trips to Alaska from 1986 thru 2003. |
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Syncro Jael
Samba Member
Joined: December 19, 2013
Posts: 2204
Location: Utah
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| Posted: Tue Sep 19, 2017 3:30 am Post subject: Re: DIY - Red Tek conversion |
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| dobryan wrote: |
| Syncro Jael wrote: |
I am pretty satisfied with my last RedTek charge. New condenser, hoses, and previous replaced components. Upper temp gauge is vent temperatures. Plenum has been removed. It took some tweaking to get the pressures where I wanted them.
Link
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Ron, what pressures did you finally end up with and at what intake temp? Thanks!  |
1800 rpm. 27 low 194 high. 91° ambient. Radiator fan on high speed. Box fan in front of condenser. I was sweating! (1) can charged to the high side of an evacuated system, engine off, was enough for the compressor to engage. I slowly added another can and a little more of the third to the low side. All cans were loaded upside down as per RedTek instructions.
It was interesting to note that while sitting still, doing the charge, my vent temps never got below the low 50°s. This was because the rear hatch was open to an open engine compartment and exposed to the sun. So I'm sure the temps crossing the evaporator was at least 100° If not higher.
The video was taken at highway speeds of 65-70 mph across the Utah desert road. Earlier in this thread you will read that I struggled get low vent temps in the 30°s. This is with my temperature bypass switch on. On evaporator fan speed 1 the vent temps got down to 30° and was still dropping, so I turned up the fan setting so as to not freeze up the evaporator. Once I flipped the bypass switch back off, vent temps stayed in the lower 40°s as the compressor now cycled on and off.
The vent temperature gauge lets me keep track of how the AC system is working. Humidity affects it as does low rpms and traveling speeds. Removal of the rear plenum made a tremendous difference in the airflow to the front of the van. I no longer need the small auxiliary fans pointed at us. TK was rather gruff, but he really did help me understand my AC system and how to attain vent temps in the 30°s. Thanks TK.
I now see a delta of 50° or over at highway speeds between the ambient temperature and my vent temperatures. Fan speed 2. This is with our low humidity levels here in Utah.
_________________
1987 Syncro Westfalia Hightop - NAHT
Subaru EJ25 Forged Frankenmotor, Triple Knob.
Jael = (Mountain Goat) |
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dobryan
Samba Member
Joined: March 24, 2006
Posts: 16501
Location: Brookeville, MD
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Syncro Jael
Samba Member
Joined: December 19, 2013
Posts: 2204
Location: Utah
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| Posted: Tue Sep 19, 2017 6:18 am Post subject: Re: DIY - Red Tek conversion |
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| dobryan wrote: |
| Thanks! Yep, that humidity really makes a difference. I think I am over charged. I'll slowly reduce the amount in the system. My low side is in the upper 30's close to 40. |
Yes, on a previous charge I followed the RedTek instructions and charged to 30psi on the low side. I tweaked it down and noticed that the vent temps also lowered. I have found that 27-28 psi was the sweet spot for my system.
This is one area that more is not better.
Cheers....
_________________
1987 Syncro Westfalia Hightop - NAHT
Subaru EJ25 Forged Frankenmotor, Triple Knob.
Jael = (Mountain Goat) |
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Guybrush
Samba Member
Joined: August 08, 2015
Posts: 453
Location: Arizona
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| Posted: Fri Sep 22, 2017 7:01 am Post subject: Re: DIY - Red Tek conversion |
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What is the best way to deal with an overfilling?
I just connected my new system, everything is new except the evaporator. It's running on a Bostig config, with the appropriate compressor. I filled it with Enviro-Safe, which I believe is the same thing as Red Tek. It was a bit low after one can, but I wasn't ready for how fast it filled up on the second can, and got a pressure of over 40 on the low side. It was a bit low on the high side but perhaps because the van was just idling, which made me want to add more.
It's working, there is cold air out of the vent (of course, doing that close to sunset is not a great indication of how it's going to perform in the dead of summer out here in AZ) but I'm sure it could be colder, especially since the compressor is not cycling very often. I was also use fan speed 2 only, because my 50A fuse is blown, pending replacement (tested with a wire but didn't leave that on).
So, how to lower the low side pressure a tad? |
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Syncro Jael
Samba Member
Joined: December 19, 2013
Posts: 2204
Location: Utah
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| Posted: Fri Sep 22, 2017 7:14 am Post subject: Re: DIY - Red Tek conversion |
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This is one reason I chose REDTEK. With the compressor off, slowly let some pressure off on the LOW SIDE, very slowly so you do not loose oil. Or take it to an AC shop. They would not do mine because it was not R12 or R134a. So they had no use for the product.
ENVIRONMENTAL ISSUES:
Red TekŪ 12a is a natural formulation of environmentally friendly Alkane products. They have a very short atmospheric lifetime-weeks and months vs 100's of years for CFC-R12. Once released into the atmosphere RED TEKŪ 12a breaks down into carbon dioxide and water. Although carbon dioxide is a greenhouse gas, it is a very weak one. The significant effect of carbon dioxide on global warming is due to very large quantities released through burning fossil fuels for power generation. The amount released by the use of Alkane / Hydrocarbon refrigerants would be an extremely low proportion of the overall global total.
RED TEKŪ 12a contains no chlorine or bromine and therefore has "NO" ozone depletion potential. Its global warming potential is related to the carbon dioxide produced when it breaks down in the atmosphere. When compared to R12 or R134a in the following "Greenpeace International" comparison table, the amount of carbon dioxide is insignificant.
Refrigerant RED TEKŪ 12a R12 R134a
Global warming potential (100 year basis) 8 7300 1200
RED TEKŪ 12a is considered one of the most environmentally friendly refrigerants available in the marketplace. Greenpeace International has included RED TEKŪ 12a in their "Preferred Products List", World Wide.
_________________
1987 Syncro Westfalia Hightop - NAHT
Subaru EJ25 Forged Frankenmotor, Triple Knob.
Jael = (Mountain Goat)
Last edited by Syncro Jael on Fri Sep 22, 2017 7:31 am; edited 1 time in total |
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dhaavers
Samba Member
Joined: March 19, 2010
Posts: 7756
Location: NE MN (tinyurl.com/dhaaverslocation)
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| Posted: Fri Sep 22, 2017 7:22 am Post subject: Re: DIY - Red Tek conversion |
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| Guybrush wrote: |
| ...got a pressure of over 40 on the low side. It was a bit low on the high side but perhaps because the van was just idling... |
Before losing any refrigerant, check your pressures at 2kRPM & see where you are.
Do you have a big fan up front blowing straight into the condenser? Gotta do it right...
(Is it just me, or do I sound a little like TK these days...???) Naaah... 
Once you're at high idle & running the fan on the condenser, watch your vent temp
& make small adjustments in the amount of refrig to find your best vent temp.
Takes a little fiddling but it can make a big difference... 
- Dave
_________________
86 White Wolfsburg Westy Weekender
"The WonderVan"
<EDITED TO PROTECT INNOCENT PIXELS> |
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Guybrush
Samba Member
Joined: August 08, 2015
Posts: 453
Location: Arizona
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| Posted: Fri Sep 22, 2017 8:14 am Post subject: Re: DIY - Red Tek conversion |
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No, I don't have a big fan. I can probably use one from my workshop. The radiator fan does run though.
My question is really about how to *remove* some refrigerant though. Adding is easy enough, apparently...
I'll try at a higher RPM once I find a helper. |
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dobryan
Samba Member
Joined: March 24, 2006
Posts: 16501
Location: Brookeville, MD
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| Posted: Fri Sep 22, 2017 8:35 am Post subject: Re: DIY - Red Tek conversion |
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| Guybrush wrote: |
No, I don't have a big fan. I can probably use one from my workshop. The radiator fan does run though.
My question is really about how to *remove* some refrigerant though. Adding is easy enough, apparently...
I'll try at a higher RPM once I find a helper. |
As Ron mentioned. Slowly depress the shrader valve on the low side fitting with the engine off and cold. Try not to let any oil out.
_________________
Dave O
'87 Westy w/ 2002 Subaru EJ25 and Peloquin TBD
"To travel hopefully is a better thing than to arrive." Robert Louis Stevenson
MD>Canada>AK>WA>OR>CA>AZ>UT>WY>SD
https://www.thesamba.com/vw/forum/viewtopic.php?t=620646
Building a bus for travel in Europe (euroBus)
https://www.thesamba.com/vw/forum/viewtopic.php?t=695371
The Western Syncro build
https://www.thesamba.com/vw/forum/viewtopic.php?t=746794 |
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Guybrush
Samba Member
Joined: August 08, 2015
Posts: 453
Location: Arizona
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| Posted: Fri Sep 22, 2017 8:43 am Post subject: Re: DIY - Red Tek conversion |
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Apologies, I only saw the last message, for some reason, when I typed my reply. Thanks  |
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fxr
Samba Member
Joined: December 07, 2014
Posts: 2321
Location: Bay area CA
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| Posted: Fri Sep 22, 2017 8:56 am Post subject: Re: DIY - Red Tek conversion |
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| Guybrush wrote: |
What is the best way to deal with an overfilling?
I just connected my new system, everything is new except the evaporator. It's running on a Bostig config, with the appropriate compressor. I filled it with Enviro-Safe, which I believe is the same thing as Red Tek. It was a bit low after one can, but I wasn't ready for how fast it filled up on the second can, and got a pressure of over 40 on the low side. It was a bit low on the high side but perhaps because the van was just idling, which made me want to add more.
It's working, there is cold air out of the vent (of course, doing that close to sunset is not a great indication of how it's going to perform in the dead of summer out here in AZ) but I'm sure it could be colder, especially since the compressor is not cycling very often. I was also use fan speed 2 only, because my 50A fuse is blown, pending replacement (tested with a wire but didn't leave that on).
So, how to lower the low side pressure a tad? |
If you've only got two cans of Envirosafe in there, you need to add a bit more, not take some out. The sweet spot in my rig is 14oz - two and a third cans. With the engine off I add the first two cans to the high side, holding them upside down. Then I start the engine, run it well above idle with a shop fan on the front and add the last bit to the low side but with the can upright just letting vapour in. I've done this about four times now, as I've had to resurrect a system that apparently hadn't worked for 20 years.
_________________
Jim Crowther
1984 1.9l EJ22 Westy Wolfsburg Edition
Vespa GTS 300 |
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Guybrush
Samba Member
Joined: August 08, 2015
Posts: 453
Location: Arizona
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| Posted: Fri Sep 22, 2017 10:18 am Post subject: Re: DIY - Red Tek conversion |
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| Going by the gauges, I was at almost 50 on the low side after the second can, and about 200 on the high side. I'll go back to it this weekend by checking the pressures at a higher RPM. I didn't add anything to the high side. Only to the low side, by jumping the compressor to run. Can was sucked in very quickly. |
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Abscate
Samba Member
Joined: October 05, 2014
Posts: 22641
Location: NYC/Upstate/ROW
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| Posted: Fri Sep 22, 2017 10:51 am Post subject: Re: DIY - Red Tek conversion |
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Methane is a potent greenhouse gas, and instead of trying to write a false narrative on the science the MFG should just correctly point out that the contribution of refrigerant to the world wide methane load is neglible..I will swag it as about 50 ppb of the total load
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Guybrush
Samba Member
Joined: August 08, 2015
Posts: 453
Location: Arizona
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| Posted: Fri Sep 22, 2017 12:14 pm Post subject: Re: DIY - Red Tek conversion |
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So I decided to go back to it.
Learning a few things in the process. I understand the need for the fan now. Without any air going over the condenser, the system can't work. If I have the compressor running at that time, the high pressure just climbs, and climbs, but there is no cold air. I suppose the trinary switch normally catches that (I bypassed it for charging).
Once the radiator fan kicks in, and the compressor is running, I got the van to go at an estimated 2000 or 2200 RPM from the back (real RPM from the OBD2 system is always higher than what the gauge says), it's hard to see from out there, but it's about right. At that point, the pressures get closer to what they're supposed to be, and cold air comes out. With higher RPM, the low side drops too, below 30. I ended up finishing that second can and adding a bit more from a third. Not sure how much. Just adding it in quick bursts.
I decided to leave it this way for the moment, as I need things to cool down so I can make a heat shield between exhaust and compressor. It gets very hot down there, can't take off the couplers without gloves on.
I might revisit this weekend by rigging a fan in front of the van, and find a thermometer, but the question is...shouldn't the radiator fan come on at low speed when the compressor runs? I'm not positive that's standard depending on the year, but should probably be the case. There's a lot of low speed and idling in the heat out here, more than highway driving. |
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Guybrush
Samba Member
Joined: August 08, 2015
Posts: 453
Location: Arizona
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| Posted: Fri Sep 22, 2017 12:26 pm Post subject: Re: DIY - Red Tek conversion |
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Actually, that last bit about the radiator fan might be due to the specs of the trinary switch, which are these:
Fan on at 242 PSIG, off at 185 PSIG. Low opens at 29 PSIG. High opens at 377 PSIG closes at 369 PSIG
Looking at those numbers, I might need to add yet a bit more refrigerant...
Edit: actually, scratch that, I realized the switch is on the high side, so it has nothing to do with the low side pressure.
And perhaps add a manual fan switch to force low speed on when using A/C around town.
Last edited by Guybrush on Fri Sep 22, 2017 12:41 pm; edited 1 time in total |
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ledogboy 
Samba Member
Joined: September 19, 2005
Posts: 578
Location: Scappoose, OR / Oakland, CA
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| Posted: Fri Sep 22, 2017 12:31 pm Post subject: Re: DIY - Red Tek conversion |
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The radiator fan should come on whenever the A/C is on.
_________________
1986 Westy Weekender
Now a full camper
1.8t Syncro conversion
Some people call him Maurice... |
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Alan Brase
Samba Member
Joined: March 28, 2004
Posts: 4532
Location: Cedar Falls, Iowa
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| Posted: Fri Sep 22, 2017 1:04 pm Post subject: Re: DIY - Red Tek conversion |
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| Syncro Jael wrote: |
...
1800 rpm. 27 low 194 high. 91° ambient. Radiator fan on high speed. Box fan in front of condenser. I was sweating! (1) can charged to the high side of an evacuated system, engine off, was enough for the compressor to engage. I slowly added another can and a little more of the third to the low side. All cans were loaded upside down as per RedTek instructions.
It was interesting to note that while sitting still, doing the charge, my vent temps never got below the low 50°s. This was because the rear hatch was open to an open engine compartment and exposed to the sun. So I'm sure the temps crossing the evaporator was at least 100° If not higher.
The video was taken at highway speeds of 65-70 mph across the Utah desert road. Earlier in this thread you will read that I struggled get low vent temps in the 30°s. This is with my temperature bypass switch on. On evaporator fan speed 1 the vent temps got down to 30° and was still dropping, so I turned up the fan setting so as to not freeze up the evaporator. Once I flipped the bypass switch back off, vent temps stayed in the lower 40°s as the compressor now cycled on and off.
The vent temperature gauge lets me keep track of how the AC system is working. Humidity affects it as does low rpms and traveling speeds. Removal of the rear plenum made a tremendous difference in the airflow to the front of the van. I no longer need the small auxiliary fans pointed at us. **TK was rather gruff, but he really did help me understand my AC system and how to attain vent temps in the 30°s. Thanks TK.**
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Truer words never spoke regarding the famous TK.
Pressure and performance are very charge sensitive BUT EVEN MORE sensitive to air flow across the condensor and evaporator. Shop type fans around the condensor will help.
And sitting still with the evaporator sucking hot air from the engine compartment will yield very high low side pressures compared to real life where the return air might be in the 60's F.
So the answer is, just get it close then take it for a drive. I would try to keep low side high enough so there is never a chance of the evaporator icing. 38degrees, I think.
ALSO, the more charge in the system the greater is the capacity to remove the heat. SO:
More refrigerant- higher pressures, higher boiling temps in the evaporator, higher capacity
Less refrigerant - lower pressures, temps, but less capacity.
Humidity is pretty irrelevant to the system except the there will be much greater condensate dripping out the back with greater humidity. Humidity has a GREAT effect on humans, whose bodies are cooling by expiration and evaporation of water. It's all about evaporation and vapor pressure with us too. But the condensation takes place remotely. And the pump is huge.
Al
_________________
Al Brase
Projects: 67 sunroof bug, 67 Porsche 912 Targa, 70 Westy
Dec 1955 Single Cab pickup WANT 15" BUS RIMS dated 8/55, thru 12/55
To New owners: 1969 doublecab, 1971 Dormobile
Vanagons:
80 P27 Westy JUL 1979, 3rd oldest known US
83 1.6TD Vanagon, 87 Wolfie Westy daily driver, swap meet home |
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Guybrush
Samba Member
Joined: August 08, 2015
Posts: 453
Location: Arizona
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| Posted: Fri Sep 22, 2017 1:13 pm Post subject: Re: DIY - Red Tek conversion |
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| Thanks. I will take it for a drive after I make the heat shield and get a thermometer to hook up near the fans. True that it gets very hot in there while fiddling with all this and bringing up the RPM. I would have liked to have this working before the summer heat, but the whole project was much more involved. |
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Guybrush
Samba Member
Joined: August 08, 2015
Posts: 453
Location: Arizona
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| Posted: Sat Sep 23, 2017 6:29 pm Post subject: Re: DIY - Red Tek conversion |
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I spent my day retrofitting a weekender table into my van, so I didn't get a chance to drive. However, the lack of automatic engagement of the rad fan was due to the blown 50A fuse. The schematics showed that, but replacing the fuse confirmed it. With a new fuse in place, the radiator fan came on right away as I started the vehicle cold with the A/C switch on, and the compressor started cycling quickly as well. Previously, it would only turn on when the van had heated up enough for the rad fan to come on for the cooling system.
I'm pretty happy about that, because my to-do list is long enough. |
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