Pressure Range

[tanveerkuet]

Hi i am a newbe in refrigeration. I am trying to build a basic refrigeration system. But having difficulties hoe to measure pressure in the compressor outlet and evaporator outlet? Please help me.

[expat]

Without wishing to seem obtuse could you tell me why you want to know these measures?

Do you need to know if something is fonctioning correctly? Do you wish to find out if there is or isn't any gas left in a system or are you merely curious as to the workings?

Once I undestand what you want to do I can help you.

[taz24]

Hi i am a newbe in refrigeration. I am trying to build a basic refrigeration system. But having difficulties hoe to measure pressure in the compressor outlet and evaporator outlet? Please help me.

Compressor outlet could have a service valve.
Fit gauges and read pressure.
If no valves fitted then there are small shraider valves that can be fitted into the line anywhere you want. You could fit these then fit gauges and read pressure.

taz.

Ps if there is gas in the system and no service valves to access the point you want you will have to remove the gas first before you cut into the system to braze the new valve,

[tbirdtbird]

"if there is gas in the system and no service valves to access the point you want you will have to remove the gas first before you cut into the system to braze the new valve"

Taz what about the saddle valves you sweat on a live line then insert a special schrader/piercing gizmo then screw the cap on tight to make a leak-pruf perm. schrader anywhere ya want 'on the fly'..they've bailed me out...JB has them here A32800

just ad www to this url:
[ jbind.com/catalog_multi-page/Page_37-40_JB_Industries_2007_catalog.pdf]

[expat]

High Tbird, I've seen these things and often wondered if they were viable. Your saying they've bailed you out a few times, and I must admit they're not an expensive addition to the tool box. But do they hold the gas like a brazed on schrader?

[tbirdtbird]

Greatest thing since sliced bread. Here is a pic of one I put just ahead of a suction accum. in a -40*F R404a system so I could add liquid 404 on the low side. (slowly of course). Depends on your skill. I have used 95-5 on a bunch of them no trouble. Actually probably over the top since 404a has such a low glide (? 1.5??) that my highly knowledeable company engineer says don't worry about adding gas. BE SURE to put the little teflon ring-gasket on!!! Sometimes they have fallen out of the pkg before you get it. As you screw down the brass cap (hold the other hex with a separate wrench) it pierces, seals on the teflon, and crimps the pin in all at the same time. Schrader is inside the pin from the factory. Done!!!DSC00795.JPG

DSC00796.JPG

[tbirdtbird]

One more (C&D brand)DSC00797.JPG

[expat]

Ok, thanks I see what your saying know. I thought it was something you could attatch to a charged system. BTW, what brazing rods did you use on that valve?

[tbirdtbird]

Yo *do* attach to a charged system. (or uncharged too)

[rrvilla920]

Wouldn't a simpler way just be to take temperatures in the necessary parts of the system and then use pressure/temperature relationship to know whats going on?

[expat]

Cześć rrvilla920, we're getting a bit off subject as Tanveerquet wanted to know how to get pressure readings from a compressor, then Tbird said that these neat little add-on valves were useful, then I wanted to know if they could simply be applied to a pipe on a charged system and remain leak free to which he replied they could (hold on, I'm going to take a breath,.... that's better)

Now I'm confused because in your picture Tbird the valve is brazed on, so the pipe had to be empty.?

[tbirdtbird]

Please look at the jpgs i sent, they will help. So you braze on the main part of the fitting **whether system charged or not**. Or pump down. Leak test your brazing skill if you wish as the pic shows. You have not yet actually entered the interior of the copper tube. Insert the special hardened steel core which has a piercing tip on it. Be sure the teflon gasket is on as mentioned above and as depicted. This is **very important** . Now put the brass cap on finger tight. Now use 2 wrenches to finish screwing in the special core....As you do so:
1 the special tip will piece the copper
2 the teflon gasket will seal the special core to the special main brass body
3 the brass cap will also crimp the brass around the top of the special core so that it cannot be removed or cannot come out. This special core is threaded internally for the usual Schraeder core.

Done!!

1 2 and 3 all happen at the same time. Your refrigerant charge is protected.

I build up some extra 95-5 around the joint. I also tin everything ahead of time which makes it a very simple job. I keep a few of the common sizes on hand. Check the JB catalogue or the C&D catalogue on-line.

This may save some of you guys time, and better yet aggravation. Can't explain it any better. Suggest you buy one (pennies) and play with it at home. I have learned at lot from this site and thought I'd toss back a pearl. There are some really sharp guys here.....