Pressure switch necessary on a/c? - Page 2 - Chevelle Tech
Heating & Cooling Heating, cooling and air conditioning Sponsored by:Cold-Case Aluminum Radiators

 11Likes
Reply
 
LinkBack Thread Tools Search this Thread Display Modes
post #16 of 21 (permalink) Old Feb 9th, 20, 11:53 AM
Gold Founding Member
Administrator
 
Join Date: Aug 1998
Location: near Kansas City
Posts: 62,062
Garage
Re: Pressure switch necessary on a/c?

Quote:
Originally Posted by DUTCH MAX HEADWORK View Post
1972 Chevelle and most other Chevys of that year.

72 A6 compressor had the superheat switch mounted on the backside and the thermal limiter switch was on the fender.
Oh, it was 72 then, I was thinking 74
DUTCH MAX HEADWORK likes this.

.
.
.
.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Dean is offline  
Sponsored Links
Advertisement
 
post #17 of 21 (permalink) Old Feb 9th, 20, 1:13 PM Thread Starter
Lifetime Premium Member
Brandon
 
Join Date: Dec 2018
Location: Pflugerville, Texas
Posts: 48
Re: Pressure switch necessary on a/c?

I traced the compressor wire on my 71 and it runs to the ambient temp sensor on the evaporations box. I'll just tap the pressure switch in those wires.

Ive got everything ordered to replace everything on the a/c system and reuse the existing evap box. With seeing some debris and crud in all of the lines I don't want to skimp on something and have to do it over again. And the previous owner already replaced the heater core, blower motor, and complete car wiring harness so I should be pretty good.
DUTCH MAX HEADWORK likes this.
bjl95mustang is offline  
post #18 of 21 (permalink) Old Feb 10th, 20, 5:20 PM
Tech Team
 
Join Date: Aug 2018
Posts: 388
Re: Pressure switch necessary on a/c?

Quote:
Originally Posted by swampy 6x6 View Post
HI
Blow out plugs
compressor and receiver driers can have them

Wouldn't that be sort of a designed-in epa violation? Or maybe not back when these were made...

'71 chevelle, 468, TH400, 12 bolt posi w/3.08's, drinks a lot of 87 octane.
v8440 is offline  
 
post #19 of 21 (permalink) Old Feb 10th, 20, 5:48 PM
Tech Team
 
Join Date: Oct 2019
Posts: 142
Re: Pressure switch necessary on a/c?

HI
Those inbuilt safety plugs only operate when the situation of system catastrophic failure occurs . Controlled explosion of system eg in the event of an accident .

If the EPA was that concerned ,, the operation of system high pressures would be specified . The high side pressures are by far responsible for the majority of leaks in most vehicles .
swampy 6x6 is online now  
post #20 of 21 (permalink) Old Feb 10th, 20, 8:45 PM
Gold Founding Member
Administrator
 
Join Date: Aug 1998
Location: near Kansas City
Posts: 62,062
Garage
Re: Pressure switch necessary on a/c?

Quote:
Originally Posted by swampy 6x6 View Post
hi
In various GM cars with an orifice tube and accumulator , the super heat switch is a pressure switch senses ultra low pressures when the evaporator is full of cold low pressure liquid and sending excess liquid back to the compressor . The design is a safety aspect for the compressor . If the system is working properly the safety switch should not be used .

In the 90`s even some GM cars were retrofitted with such devices .

Biggest issue with those is some factory accumulator / POA / orifice type aircons were designed really badly by GM ..
Although not every model .

A thermal switch is an overheating compressor disconnect and /or operates a warning light/ac light flashes . GM pls many other brands use this idea
OOPS, I thought this was about 64-72 Chevelle A/C systems.

.
.
.
.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Dean is offline  
post #21 of 21 (permalink) Old Feb 10th, 20, 10:59 PM
Tech Team
 
Join Date: Oct 2019
Posts: 142
Re: Pressure switch necessary on a/c?

HI
Most factory Gm are now not running the exact factory spec
refrigerant change to start with.
upgraded R134a compressor , H/D condenser, R134a evap core ,thermostat used a lot .Poa valve not always used .
accumulator instead of r/drier .
In the auto a/c industry upgrades occur often not just Chevelles . Older GM systems do not perform as well as more modern independent designs by some specialists eg Nippon Denso who supply to the auto industry .
Now if u upgrade properly any poor performing older GM a/c can be improved . Keep in mind R134a is low performing refrigerant compared to R12 . That's why upgrades are needed to compensate in the first place .

Qualified Mechanic with years of a/c specialist experience and the appropriate licensing
If it has had wheels Ive fixed or help fix the A/c . Trains /trucks /buses/small planes /cars .
If it come in the shop I`m not refusing to work on it .
LeoP likes this.
swampy 6x6 is online now  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevelle Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address. Note, you will be sent a confirmation request to this address.

Email Address:
OR

Log-in










Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome