When I first converted my system to 134 and got it working, I put in a new
receiver-drier.  I don't recall if I looked at the sight glass then.  I
probably just put in the recommended amount of refrigerant.  When I started
using butane/propane I think that I saw something on the autorefrigerants
website that implied that the sight glass would not be helpful.  Since then
I have ignored it.

Larry A.

On Fri, Aug 30, 2013 at 10:40 AM, Mike Finkbiner <mike_l_f@hotmail.com>wrote:

> Larry -
>
> That's helpful information.
>
> Have you ever checked your sight glass?  I keep coming back to that
> because I have heard conflicting stories.  With an R-12 system, you will
> likely see bubbles when you start the AC, but then it should look generally
> clear while it's running.  One RedTek rep said their product behaves the
> same, but admitted he was more familiar with household systems.  Another
> said that it's considerably lighter than R-12, which is why you only use
> 1/3 as much (17oz instead of 51), so you will always see bubbles.
>
> I'm trying to get some field verification from other people using
> hydrocarbon blend refrigerants.
>
> The sight glass is on top of the receiver/dryer, visible through the front
> of the rear, driver's side wheel well.  I generally use a Q-tip or similar
> with a solvent to reach in and clean the glass, then shine a flashlight to
> see what's happening.
>
> Mike Finkbiner
>
> mike_l_f@hotmail.com
>
>
>
>                    You can't see a thought, you can't measure, weigh, nor
> taste it - but thoughts are the most real things in the Galaxy.
>            - Richard Baslim
>
> Date: Fri, 30 Aug 2013 09:08:32 -0400
> Subject: Re: RedTek and the Sight Glass
> From: lalofs@gmail.com
> To: mike_l_f@hotmail.com
> CC: vanagon@gerry.vanagon.com
>
> Mike,  I use ES-12a from autorefrigerants.com.  I'm not sure, but I am
> assuming that RedTek is a similar butane/propane refrigerant.Your pressure
> and temperature numbers sound nearly normal to me.  My system leaks enough
> that I typically add one 6 oz. can per season.  When it is well charged, I
> usually see a temperature drop of 25 to 30 degrees, measured with an IR gun
> at the intake and output at the rear unit (duct to the front has been
> removed).
>   Of course when the sun has been shining on the back of the van and the
> intake air is 90 or 100F, the air coming out doesn't feel very cold at
> first.  After going down the road for a while, it gets caught up and we
> start backing off on the fan and the temp control.
>
> Larry A.
>
>
> On Thu, Aug 29, 2013 at 9:47 PM, Mike Finkbiner <mike_l_f@hotmail.com>
> wrote:
>
> Dennis -
>
>
>
> Sadly I have no way to measure the high side pressure.  I was hoping to
> not have to get set up as an AC tech, and we'll see how it goes.  The
> radiator fan isn't running at high speed.   It would still be interesting
> to hear from anyone else who is using RedTek what they are seeing in their
> sight glass.
>
>
>
>
> Today I got a replacement low-pressure valve adapter which doesn't leak
> when it's screwed on, so I was able to re-test the pressure.  Before
> starting the engine, ~ 70 lbs.  After starting it dropped to ~ 34 lbs,
> right in where the RedTek folks recommend.  Not sure why it dropped from
> when I was loading the refrigerant, but there it is.
>
>
>
>
> After running for 10 minutes or so I was getting ~ 52 degrees out of the
> vent on fan speed 2.  Ambient temperature in the garage ~ 75.   I shut up
> the engine compartment and went for a drive.  After about 15 minutes, the
> vent temp was just under 50.
>
>
>
>
> The condenser up front is pretty clean and seems warm, but not hot.  At
> this point I think I'm going to run with it for a bit.  If it can't drop
> more than 25 degrees below interior temperature I gather something isn't
> right, but I need to know more about how to dig into the system to find out.
>
>
>
>
> - Mike
>
>
>
> Mike Finkbiner
>
>
>
> '87 Westy
>
> Moscow, Idaho
>
> mike_l_f@hotmail.com
>
>
> <SNIP>
>