65fury

thats right didn't do that evaporator thing to the ac and filled it up, i didn't have time to evap it so i just filled it, and it blows cold, but not that cold, does evaping the system make that big of a difference?? thanks



jason

Mt Ram

Yes!!!!!!!

loch

They can be purged instead but even that doesnt work as well. If the system was left open for more than a few minutes it has air and water in it,,niether is a refriderant.

Jim Lane

The reason to evacuate the AC system is by lowering the pressure to 28-29 inches of mercury the moisture will boil out at ambient temperatures.
The refrigerant will react with the moisture and create acid and corrode the system.
Also the moisture in the system can block the metering passages in the orifice tube or in the H-block and cause it to stop cooling, a common scenario is it cools good when it is cool out or at night but is warm when it is hot out.

The system in a vacuum also helps draw in the new refrigerant when it is being recharged.

You should not have been able to install a full charge.
You can buy air-powered vacuum pumps fairly cheap or you can remove the compressor from an old freezer and make a suitable evacuation pump.

I have 4 vacuum pumps for AC, my favorite one I bought from an industrial surplus.
It is an Edwards E2M2 ¾ hp diffusion pump that was on an electron microscope and is certified to 1 micron. This thing really sucks.
Jim

JDGnut

As others have said.. its now charge with air.. and freon.. (134a??) (with moisture..) Yes.. its going to make a difference...
I have not had very good luck with my AirVac and being able to see it boil out the moisture.. ( I'll pull a vacuum on a glass container to see the effects of the vacuum.) My gauges pull down.. but nothing happens inside.. I'd always use an electric pump when you can... (not always possible out in the field.)
134a is picky on the amount.. a little too much and it can hurt your duct temps... and high side pressures.. as it gets hotter outside, the more your problems will show..
Also, I'd stay away from the sealers.. most react with air.. If you are looking for a leak.. try adding some dye to the system.. it may take a little while for it to show up.. (and you'll need a light to find the leak.)

I'd search around.. I bet someone close to you has a v-pump you can use..
Good Luck..
Bryan

pred

Also if the moisture decides to be a few drops, and hits the compressor which is designed to compress a vapor into a liquid, and liquid is hitting it, It will not be happy for long!

BC847

What moisture in an air conditioning system does is:

- Combine with the compressor's oil to form sludge and acid(s) which are corrosive to the refrigeration systems components.
- The above is compounded when the hot, high pressure refrigerant passes through the compressors exhaust valve(s) (point of hottest refrigerant temperatures).
- When passing through the refrigerant's metering device be-it capillary tube(s) or thermostatic expansion valve, given enough, the moisture can freeze restricting if not blocking the flow of refrigerant.




The way moisture is removed from a refrigerant circuit is to (as said above) impose a very deep vacuum so as to reduce the boiling point of the liquid be it water or otherwise. As Jim Lane has pointed out, many pull down to 28 ~ 29" of mercury though to be thorough, proper refrigeration practice mandates one pull the system down to a static level of 300 to 500 microns*. The Micron range is not read with typical HVAC service manifold gages (not even close). One must use an electronic gage. No way around it.
After reaching 300 to 500 microns static vacuum, after ten to 15 minutes, if the vacuum rises to approximately 1500 microns, then you still have moisture in the system. If the vacuum rises still further (all the way up to atmospheric), then you have a leak.




Finally, having assured the refrigerant circuit is dry, a chemical desiccant drier is included in the sealed refrigerant circuit that will adsorb/absorb any moisture/acid that may form during abnormal system operation (typically high compressor operating temperature due to running with a low refrigerant charge (very high superheat).



FURTHER: The HVAC/refrigeration vacuum pump not only dehydrates the refrigerant circuit as mentioned above, it also evacuates the refrigerant circuit of any non-condensible gases be it air, nitrogen or otherwise. Any of the aforementioned left in a refrigerant circuit will present as exaggerated head pressures. Those non-condensible gasses will typically "Stack Up" in the condenser coil. Those areas of the coil where the non-condensible gasses are stacked, will not allow the refrigerant to give up it's heat resulting in reduced system capacity.


Hope this helps.





*The vacuum level is determined by the pressure differential between the evacuated volume and the surrounding atmosphere. Several units of measure can be used. Most refer to the height of a column of mercury - usually in.-Hg or mm-Hg. The common metric unit for vacuum measurement is the millibar, or mbar. Other pressure units sometimes used to express vacuum include the interrelated units of atmospheres, torr, and microns. One standard atmosphere equals 14.7 psi (29.92 in.-Hg). Any fraction of an atmosphere is a partial vacuum and equates with negative gage pressure. A torr is defined as 1/760 of an atmosphere and can also be thought of as 1 mm-Hg, where 760 mm-Hg equals 29.92 in.-Hg. Even smaller is the micron, defined as 0.001 torr.

Vacuums fall into three ranges:

* rough (or coarse), up to 28 in.-Hg
* middle (or fine), up to one micron,
* high, greater than one micron.

* As found here ~ http://www.hydraulicspneumatics.com/...460/Pneumatics

65fury

WOW that about answers my questionand everything else i wanted to know and not know about a/c, thanks


jaosn