The banner above is an advertisment - if it asks you to download software, please ignore.
Site News - 7/1: Members: Log In to See Fewer Ads! | 5/28: SAAB Evolutions/TSN T-Shirts $14
[General | Members | C900 | 9000 | NG900 & OG93 | 93 | 95 | NG95 | 99 | Sonett | Vintage Models | Clubs | Other Cars | FAQs | Gifts | Member Photo Galleries | Member Directory | Classifieds | Manuals | *Buddy Registry | *Mileage Registry | Polls | What's New | Raffle | Photo of the Month | Sponsors]

General Bulletin Board
[Subscribe to Daily Digest]
(Search Author's Posts: e.g. Keyword:username)*Members Only

[Main General Bulletin Board | BBFAQ | Prev by Date | Next by Date | Post Followup ] Member Login / Signup - Members see fewer ads. - Latest Member Gallery Photos
Re: Vacuum pump
Like This Post: - Subscribe to Daily Digest for this Bulletin Board
Posted by Gene N [Email] (#1094) [Profile/Gallery] (more from Gene N) on Thu, 20 Jul 2006 06:34:16 Share Post by Email
In Reply to: Vacuum pump, yaofeng, Thu, 20 Jul 2006 05:46:43
Alert me when someone posts in this thread:
Members do not see ads below this line. - Help Keep This Site Online - Signup

There at least two types of electric vacuum pumps. Single stage and dual stage. The two stage pulls a better absoulute vacuum, but is more expensive as you would imagine. I have a single stage pump, and it works just fine, pulls to about 29.8 inches of Hg or 150 microns.

The vacuum pump that works off compressed air uses Bernoulli principle to evacuate the system, so the pump has no moving parts. They do work, but they cannot pull as high a vacuum as the electric vacuum pumps (28 inches of Hg if you are lucky), require a robust compressed air flow (5 CFM at least), and reportedly take quite a long time to do the job.

The idea behind the pump is remove all the air from the system before charging, with particular attention to water vapor. In an A/C system, water vapor turns to ice and clogs up the expansion valve. The water is removed by lowering the pressure in the system to the point where the water is boiling at the ambient temperature (say 20 degrees C). The higher the vacuum, the lower the boiling point.

The venturi vacuum pump requires no maintenance and costs $10 from Harbor Freight. The electric pump requres changing the vacuum pump oil periodically and typically costs $200-$300 new. I got a used one in excellent shape for $100 a few years ago, and have used it dozens of times.

My recommendation is to shop around for an electic pump.



posted by 208.20.22...

Posts in this Thread:
Alert me when someone posts in this thread:
Members do not see ads below this line. - Help Keep This Site Online - Signup
Post a Followup

No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.

Name: Member Login / Signup - Members see fewer ads. - Latest Member Gallery Photos
E-Mail: (Optional)
Re-Enter E-Mail: (Confidential & Secure - Not revealed to other users!)
Note: Please check your spam folder for BB responses.

Subject:

Posting rules are simple - No for sale/wanted ads may be posted here - use the site classifieds.
You may not cross-post your message to multiple BBs.
Not permitted: political/religious topics and being disrespectful (personal attacks, insults, etc...).
 Site Members do not see any red text, inline ad links, bottom of page anchor ads, box ads, or anti-spam check.

Message: (please no for sale/wanted classifieds - post those in the Saabnet.com Classifieds)
Links are now automatically made active, no need for any special code (or use the Option Link field below) - don't put links in () or end with a '.'
To add inline images to your post, use [img]http://www.domain.com/img.jpg[endimg] (or use the Optional Image Link field below).

Links are now automatically made active, no need for any special code (or use the Option Link field below) - don't put links in () or end with a '.'
To add inline images to your post above, use [img]http://www.domain.com/img.jpg[endimg] (or use the Optional Image Link field below).
Optional Link: (e.g. http://www.saabnet.com/)
Link Title: (Optional)
Optional Photo/Image Link: (e.g. http://www.saabnet.com/img.jpg)
Photo/Image to Upload: (Please be patient while file uploads)



StateOfNine.com
SaabClub.com
Jak Stoll Performance
M Car Covers
Ad Available

The content on this site may not be republished without permission. Copyright © 1988-2024 - The Saab Network - saabnet.com.
For usage guidelines, see the Mission & Privacy Notice.
[Contact | Site Map | Saabnet.com on Facebook | Saabnet.com on Twitter | Shop Amazon via TSN | Site Donations]

Random Saabnet.com Member Gallery Photos (Click Image)
This is a moderated bulletin board - Posting is a privilege, not a right. Unsolicited commercial postings are not allowed (no spam). Please, no For Sale or Wanted postings, SERIOUSLY. Classifieds are to be listed in The Saab Network Classifieds pages. This is a problem solving forum for over 250,000 Saab owners, so expect to see problems discussed here even though our cars are generally very reliable. This is not an anything goes type of forum. Saabnet.com has been a moderated forum since 1988. For usage guidelines, see the Saabnet.com Mission and Purpose Page. Please remember that you are not anonymous. Site Contact | Site Donations | Other Sites by SP - Poverty2Prosperity.org | Run Club Menlo Park | ScreenBot


Site Members do not see red text instructions, bottom of the page anchor ads, or box ads.
Click here to see all the Site Membership Benefits!