PDA

View Full Version : pressure testing systems







cadwaladr
11-08-2016, 01:22 AM
I have a fellow tech who pressur tests systems with a hermetic compressor basically suction open to atmosphere delivery connected to system ,me it's own or nothing any thoughts on this?

chemi-cool
11-08-2016, 05:10 AM
Pressure wise its a test but he is filing the system with moisture. poe oil is will absorb it and vacuum will not take it out. Not smart thing to do.

OFN is whats he needs.

RANGER1
11-08-2016, 09:07 AM
He would possibly generate service work for the future to clean up mess he has created.
If not to late he needs retraining.
Even in large Industrial ammonia systems we use OFN for pressure testing.

cduque
11-08-2016, 09:34 AM
If the system is new and with no oil, I don't see any risk for the system in using air as a pressure test fluid, provided that it is folowed by a good vacuum.
In a system not new the correct way is efectively to use oxygen free nitrogen.

Josip
11-08-2016, 09:55 AM
Hi all :),


If the system is new and with no oil, I don't see any risk for the system in using air as a pressure test fluid, provided that it is folowed by a good vacuum.
In a system not new the correct way is efectively to use oxygen free nitrogen.

I can agree with above ... all depend what is available on site for pressure test ... on huge plants we usually use instrumental air or huge air driers connected to air compressor/s ... the best is OFN ... but we all know life is not always simple ;)

Using hermetic compressor with an inline air drier in small systems can be acceptable ...


Best regards, Josip :)

Brian_UK
11-08-2016, 11:36 AM
Obviously not performing strength tests though.

Basic bad practice, would cancel manufacturers warranty.

sterl
11-08-2016, 07:48 PM
Compressing air for leak testing is going to introduce moisture to the circuit, and that will make the evac more difficult. You basic drier arrangement not going to do much good unless you can afford to re-expand to shift pressurized dewpoint. So: for checking out the install of 1-little evap on an ammonia circuit: Sure, go for it. For just about anything more complicated or involving a refrigerant-lubricant combination thats sensitie to moisture: You could build something; its not just a recouped hermetic....

RANGER1
11-08-2016, 09:13 PM
If he has access to OFN then no real excuse for not using it.
We don't know what type of systems we are referring too.

Possible problems could be oxidized oil entering system
Introducing different oil & contaminants into system
How is hermetic compressor controlled to prevent over pressure
How is oil level in hermetic compressor monitored?

We can't all be perfect, but at least try to do right thing.
We would want to keep it as pure as possible by not introducing anything unnecessary.

cadwaladr
12-08-2016, 12:19 AM
The type of equipment is catering equipment bottle coolers ,walk in cold rooms and yes I have told him the pitfalls he has a cut out fitted for over pressure and he does have access to ofn but says it's too expensive!