[Jack8080]

Hey guys just a general question about leak checking. So far i've read that the best leak checking method is a standing pressure check with nitrogen and a "hotshot" of r-22. Question is when doing this which access port should be used to charge this into the system and should the same access port be used to check the pressure? I know it should be charged to the systems operating pressure as stated on the manufacturers nameplate. However since the pressure is diff throughout the system would this be the liquid saturation pressure, and do all systems have access ports on the liquid line in order to check this? I know it's a lot to ask but i'm trying to piece all this great knowledge together so any response is greatly appreciated. -thanks

 

[trouble time]

I think you need to do a little more schooling on this subject before you try this on your own. There are book on basic refrigeration which would be a benefit to you. Search the web bookstores, or local libraries....

 

[Jack8080]

Well I never said i'm trying this on my own. I'm actually attending school for hvac right now. My current professor is not being very helpful so I was hoping that someone on here might clarify this a little bit more. People don't seem to answer questions on this site as much as they try to tell you what to do. So thanks for the response but no thanks. Anyone else?

 

[coolwhip]

Jack, read the rules of the site and get your post count up, then apply for pro membership. You will get plenty of answers to your questions and have access to a wealth of information.

 

[Jack8080]

Cool whip, yeah I'm trying to do that. Every little bit helps.

 

[crazeehorse]

Jack, I always use the high side access port, just make sure to take a little time for the pressure to equalize on the suction side line before you record the initial pressure reading, 5 to 10 mins. in most cases. I only use straight dry nitrogen thought for testing, due to the fact that R-22/410A pressure will change with any temperature change.

 

[hvacvegas]

Jack, I always use the high side access port, just make sure to take a little time for the pressure to equalize on the suction side line before you record the initial pressure reading, 5 to 10 mins. in most cases. I only use straight dry nitrogen thought for testing, due to the fact that R-22/410A pressure will change with any temperature change.

He's talking about finding a leak, not doing a pressure test.

 

[76olds]

Hey guys just a general question about leak checking. So far i've read that the best leak checking method is a standing pressure check with nitrogen and a "hotshot" of r-22

I don't know if I would call it the best, but that is one way you can do it if using a electronic leak detector..

Question is when doing this which access port should be used to charge this into the system and should the same access port be used to check the pressure?

Too many variables to easily answer.
It depends on what your working on and how it is set up.

I know it should be charged to the systems operating pressure as stated on the manufacturers nameplate

This is a test pressure, not a operating pressure. Big difference..

However since the pressure is diff throughout the system would this be the liquid saturation pressure, and do all systems have access ports on the liquid line in order to check this?

Most small reach in's and window a/c's don't have access ports from the factory-you have to add them. And the system should be off at this time. I know it's a lot to ask but i'm trying to piece all this great knowledge together so any response is greatly appreciated. -thanks

Your teachers in school should be teaching this and answering your questions on this.

As said before, get your post count up and become a pro member.

Hope this helps. Good luck.

 

[crazeehorse]

He's talking about finding a leak, not doing a pressure test.

That is how I find leaks, by pressure testing.

 

[Saturated Suter]

Show up early and stay late. Your teacher will answer your questions.

I would like you to think about the following:
What size is the leak? Are you checking before or after a repair is done?
What are you using to detect the leak? eg; Big Blu, electronic "sniffer", ultrasonic detector, etc. What is this oil stain doing here? What does an electric "sniffer" sniff?

Don't ever assume anything. And don't overlook the obvious.

Generally the "standing pressure test" is proformed with only dry nitrogen. If pressures remain constant according to ambient after several hours, the system has no leaks. So under what conditions would you add a shot of R-22?
What testing equipment is required to do this?

Show up early and stay late. Your teacher will answer your questions.

 

[hvacvegas]

That is how I find leaks, by pressure testing.

So, in a multi evap system, you have a micron leak SOMEWHERE.

You put nitro in. You got a leak. Now what?

Where's the leak? Which evap coil? flare nut? condenser coil? somewhere in the maze of condesner piping? somewhere in the lineset?

I think your thinking of nitro after work is completed.

We're talking about walking on a no-cool doing service.

 

[crazeehorse]

So, in a multi evap system, you have a micron leak SOMEWHERE.

You put nitro in. You got a leak. Now what?

Where's the leak? Which evap coil? flare nut? condenser coil? somewhere in the maze of condesner piping? somewhere in the lineset?

I think your thinking of nitro after work is completed.

We're talking about walking on a no-cool doing service.

What we're talking about, is referring to the original question about leak testing by using nitrogen for pressure testing to find a leak. If you would like to discuss other methods, start another thread & I will be glad discuss these methods with you.

 

[Saturated Suter]

What we're talking about, is referring to the original question about leak testing by using nitrogen for pressure testing to find a leak. If you would like to discuss other methods, start another thread & I will be glad discuss these methods with you.

The original question is: "when doing this which access port should be used to charge this into the system and should the same access port be used to check the pressure?"

That sounds like a DIY question to me.

One says tomato while the other says Tomäto.

Can't we all get along?

:cheers: To this site and our differences!

 

[RayD8630]

The original question is: "when doing this which access port should be used to charge this into the system and should the same access port be used to check the pressure?"

That sounds like a DIY question to me.

One says tomato while the other says Tomäto.

Can't we all get along?

:cheers: To this site and our differences!

Maybe not DYI. I asked some pretty out there questions on here when I was a trade school noob.

There are different kinds of leaks. In Canada, "hot shots" are not allowed and if caught doing one you can be fined or imprisoned as it's a violation of the laws made by Environment Canada. We have to use dry nitrogen.

One leak is pressure dependant. For example it only shows up after a certain pressure.

If you are in school read up in your books. As the guys have said different situations require different methods.

 

[Jack8080]

Thanks to all that responded. With different systems and different situations there of course are different tests that need to be performed to find leaks. The discussion that stemed from the question and the ways you all interpreted it was helpful indeed and will allow me to ask more precise questions in the future and pay it forward to new techs joining the field.

 

[Baloo2327]

Well I never said i'm trying this on my own. I'm actually attending school for hvac right now. My current professor is not being very helpful .....


Is the school you are attending free? If you are paying for the education, then I would damn well make sure you're getting your money's worth. You are the customer/employer. You are not paying for the privilege to just sit in his class. You are paying for the opportunity to learn. Ask questions until you understand the answers. School is the time to ask any and all questions.

 

[Jack8080]

@baloo I'm not on this site to get life advice. I got some good answers from a few of the guys so if you have nothing important to add that relates to the topic then refrain and don't waste peoples time.

 

[icoolfla]

our last resorts to find leaks are what is commonly known as an isolation test....each separate refrigerant containing component is cut from the loop, sealed, and charged with strait dry nitrogen, valve stems will have to be added to any component that doesn't already have them. charge them all up , and wait to see which one has lost pressure. there is a difference between testing for leak and then finding them for repair, and i believe you did say "finding leaks". the last thing you want is to sell new equipment to a customer with a leak in the line set. A few moths later you will return to add gas and you will have one pissed off home owner. the proses is very involved and i never look forward to doing it, this should always be done by some one with ears of experience in repairs.
hang in there.....the school i went to was similar and i eventually quit. the first year was spent on how to use tools, like a hammer, or a power drill.. keep in mind this was a night school and all of us were working in the field and im pretty sure we all new how to use a drill, but then again i have met some special people who shouldn't be allowed to use a broom. the internet is going to provide some wonderful opportunitys for the next generation of technicians and you should do as suggested, and get your post count up so you can fully take advantage of the site to accomplish your educational goals.

 

[Jack8080]

Thanks icoolfla, yeah i've been attending a local community college for hvac for the last 2 years. However, because of work and other priorities it's only been 1-2 classes at a time. Now they're canceling the program altogether b/c of lack of funding masked by lack of interest. So my last professor would rather complain about losing his job or not show up for class. The dean and other counselors I went to complain to wouldn't be of much help. I didn't want to push the subject to far as it might cost me an easy A. So next semester should be my last but that will depend on the new college I have to go to.

 

[icoolfla]

professor not showing up for class....hehehe....yah i remember that. keep in mind depending what is required in your state to get a contractors license you may not need the school. florida wants 4 years as a mechanic or supervisor and budy those 4 years fly buy in the hot sun. this is equivalent in the stats mind to vocational school, and better in my opinion. the trick is to find an employer willing to give you a chance and jumping at the opportunity of being thrown to the wolves. i wish i would have been using a resource like this a decade ago as i allso know that some times older coworkers can be reluctant to show you things as they may view you as a threat to there job. as long as you stay interested in learning you will breeze buy the rest of them and take advantage of any one willing to teach you in the field as that is wear you will learn the fastest.