Low-cost A/C efficiency boost or asking for trouble?

On Jun 12, 11:57 pm, "Ray O" <rokigawaATtristarassociatesDOTcom>
wrote:
> <ma....DeleteThis@london.com> wrote in message
>
> news:78766e64-85dc-40a8-96e9-d26c922ee57f@i36g2000prf.googlegroups.com...
>
>
>
>
>
>
>
> > Ray O wrote:
> >> <ma....DeleteThis@london.com> wrote in message
> >>news:1d90b8ca-ca75-4259-b9ae-d37e4214ce34@c19g2000prf.googlegroups.com....
>
> >> With the engine running, and the AC on, open the hood and look at the
> >> sight glass on the receiver drier.  It should look like water is flowing
> >> past
> >> the sight glass.  If you see foam, the system needs recharging.
>
> >> > Does that apply to R-134a systems?
>
> >> Yes.
>
> > Does it also apply to R-12-to-R-134a conversions, where the R-134a
> > charge is 25% less than the recommended R-12 charge?  I did what a
> > thought was a proper converson (new compressor, hoses, receiver-dryer,
> > and condenser, flushed evaporator), and the pressures and temps looked
> > right, but the sight glass was foamy at all RPMs and ambient temps.
> > The conversion still worked fine when I sold the car 5 years later.
>
> I don't have any first hand experience with R-12 to R-34-a conversions, but
> there should not be any foam in the sight glass regardless of the
> refrigerant.  The foam is caused by air in the system.  If there is air in
> the system, it probably wasn't evacuated properly prior to charging.
> --
>
> Ray O
> (correct punctuation to reply)- Hide quoted text -
>
> - Show quoted text -

Maybe we have different interpretation of 'foam', but when the sight
glass shows "air" then you are seeing a lack of refrigerant and oil.
It could simply be a void; it doesn't have to be air from improper
evacuation.

Typically on R134a systems and conversions with a sight glass, you
will see no bubbles at all once the correct charge is installed.
{While charging}, the point at which they go away is usually still an
undercharged state. Conversely, with OE R12 systems, depending on the
heat transfer and localizations within the condenser region, it is
generally accepted to see small bubbles during operation. I find this
particularly true of FWD electric cooling fan designs especially while
high speed fan operation is commanded on, and for a time after the
compressor cycles on.

Toyota MDT in MO
 >> Stay informed about: Low-cost A/C efficiency boost or asking for trouble? 

On Jun 12, 12:09 am, "Ray O" <rokigawaATtristarassociatesDOTcom>
wrote:

>
> I think liquid lines running through hot attics are insulated so that
> moisture does not condense on them and wet the attic insulation and corrode
> the lines.
>
> --
>
> Ray O
> (correct punctuation to reply)

With residential systems, the liquid line is rarely insulated.
But the suction lines always will be. The suction line is the
one that sweats. In a normal system, the liquid line should
feel "neutral" and about at ambient temp.
If it feels hot, might need to clean the condenser coils
outside..
 >> Stay informed about: Low-cost A/C efficiency boost or asking for trouble? 

"Comboverfish" <comboverfish RemoveThis @yahoo.com> wrote in message
news:997b83f5-39ca-48cd-a722-7e1b92b90c3c@y21g2000hsf.googlegroups.com...
On Jun 12, 11:57 pm, "Ray O" <rokigawaATtristarassociatesDOTcom>
wrote:
> <ma... RemoveThis @london.com> wrote in message
>
> news:78766e64-85dc-40a8-96e9-d26c922ee57f@i36g2000prf.googlegroups.com...
>
>
>
>
>
>
>
> > Ray O wrote:
> >> <ma... RemoveThis @london.com> wrote in message
> >>news:1d90b8ca-ca75-4259-b9ae-d37e4214ce34@c19g2000prf.googlegroups.com...
>
> >> With the engine running, and the AC on, open the hood and look at the
> >> sight glass on the receiver drier. It should look like water is flowing
> >> past
> >> the sight glass. If you see foam, the system needs recharging.
>
> >> > Does that apply to R-134a systems?
>
> >> Yes.
>
> > Does it also apply to R-12-to-R-134a conversions, where the R-134a
> > charge is 25% less than the recommended R-12 charge? I did what a
> > thought was a proper converson (new compressor, hoses, receiver-dryer,
> > and condenser, flushed evaporator), and the pressures and temps looked
> > right, but the sight glass was foamy at all RPMs and ambient temps.
> > The conversion still worked fine when I sold the car 5 years later.
>
> I don't have any first hand experience with R-12 to R-34-a conversions,
> but
> there should not be any foam in the sight glass regardless of the
> refrigerant. The foam is caused by air in the system. If there is air in
> the system, it probably wasn't evacuated properly prior to charging.
> --
>
> Ray O
> (correct punctuation to reply)- Hide quoted text -
>
> - Show quoted text -

Maybe we have different interpretation of 'foam', but when the sight
glass shows "air" then you are seeing a lack of refrigerant and oil.
It could simply be a void; it doesn't have to be air from improper
evacuation.

Typically on R134a systems and conversions with a sight glass, you
will see no bubbles at all once the correct charge is installed.
{While charging}, the point at which they go away is usually still an
undercharged state. Conversely, with OE R12 systems, depending on the
heat transfer and localizations within the condenser region, it is
generally accepted to see small bubbles during operation. I find this
particularly true of FWD electric cooling fan designs especially while
high speed fan operation is commanded on, and for a time after the
compressor cycles on.

Toyota MDT in MO

******************
Good point and clarification!

--

Ray O
(correct punctuation to reply)

******************
 >> Stay informed about: Low-cost A/C efficiency boost or asking for trouble?