leak testing

[Brian_UK]

Well...

Following Mitsu or Daikin Intallation manuals we need to keep pressure for 24h on comissioning...
in 2-3h some engineers could find that pressure drops or raises and depends up to air/ sun temperature.
True leak test is VAC test... Left pomp through the night and in the morning take VAC for 2-3h... if holds 4-6 Torr, then OK... If more.... use sealant, if more then 10, then put CO2 + Refrigerant or OFN + HE... or if system compicated, use distilated water...

P.S.: DIN standard is in base of EN and is more demanding. Belive me /have Tuv nord certificate for pressure test./

I intrigued to know how a pressure test of 1 bar can prove that a system is leak free.

Also what sealant do you use ?

[expat]

Also what sealant do you use ?

He uses distilled water of course

[Slatts]

Well...

Following Mitsu or Daikin Intallation manuals we need to keep pressure for 24h on comissioning...
in 2-3h some engineers could find that pressure drops or raises and depends up to air/ sun temperature.

Read, some engeneers couldn't solder well enough to hold a pressure test for 2 -3 hours.

True leak test is VAC test... Left pomp through the night and in the morning take VAC for 2-3h... if holds 4-6 Torr, then OK...

If only hold 4 to 6 Torr for 2 to 3 hours, pressurize the system with nitro and find then fix the leaks.
If the system is dry and sealed it should hold 0.5 Torr (500 micron) for 24 hours.

If more.... use sealant, if more then 10, then put CO2 + Refrigerant or OFN + HE... or if system compicated, use distilated water...

P.S.: DIN standard is in base of EN and is more demanding. Belive me /have Tuv nord certificate for pressure test./

Distalated water? Sealant? Hu?
Solder your pipes in properly.
inspect the welds with a mirror and torch, then pressure test with nitro. If the system holds the pressure test, vac it to 500 micron and if you have to do a vacuum test. If you've been putting "distalated water" in the system, don't expect it to pass a vacuum test.

P.P.S.: For companies with long service contract /5 or more years/ would recommend to keep equipment gas register and monitore leaks...
I would say loss 10% of charge in a year is bottom line... 2% is optimistic for new Daikin VRV systems...

How is any gas loss in a newly installed and commissioned system acceptable?
If your people are competent and the system has been pressure tested and vacced properly there should be no leaks in the first 12 months of operation.
I can only assume that something has been lost in the translation.

or have I missed something here?

[nike123]

I think both methods are good methods (vacuum test and pressure testing).

With pressure test you have high pressure difference at sides of leak (leak rate is high) and low accuracy (resolution) manometers to test leak and also influence of temperature change on test gas pressure.

On the other end, you have small pressure difference (1 bar) between sides of leak (leak rate is small but still present), but very precise and sensitive instrument to detect that small leak rate, and very, very, very small influence at reading of temperature change of gas remained in vacuumed pipes.

To me it looks like both methods are equally good with one key difference. If some welds are mechanically weak, pressure test will make them to open and leak but vacuum test will never disclose them.

That is why I will always make first pressure test and then vacuum test on systems where welds are involved.
On split systems with pipes in one piece, only vacuum test is sufficient.

That is my 2 cents.

Also, keep in mind this:
http://www.refrig.com/bigblumanual3....RTHING%20LEAKS

[Peter_1]

To me it looks like both methods are equally good with one key difference. If some welds are mechanically weak, pressure test will make them to open and leak but vacuum test will never disclose them.

That is why I will always make first pressure test and then vacuum test on systems where welds are involved.
On split systems with pipes in one piece, only vacuum test is sufficient.

According EN378-2008, all systems must pass a strength test at a predetermined pressure and a leak test. Both are serving a different purpose. It's not leak testing or pressure testing, it's and ..and

[nike123]

According EN378-2008, all systems must pass a strength test at a predetermined pressure and a leak test. Both are serving a different purpose. It's not leak testing or pressure testing, it's and ..and

Peter, my country is not in EU (and probably will not be) and we are not obliged here to follow that norms. Our norms are still harmonizing with EU regulation.

I wrote that from perspective of common sense and not from perspective of norms and regulations.

That is my 2 cents.

Also, in mini split systems with pipes from one piece, Indoor and outdoor unit is already tested and comes with certificate and pipes are tested and comes with certificate so there is nothing to strength test.

[Peter_1]

Peter, my country is not in EU (and probably will not be) and we are not obliged here to follow that norms. Our norms are still harmonizing with EU regulation.

I wrote that from perspective of common sense and not from perspective of norms and regulations.

Ok, you're right

Also, in mini split systems with pipes from one piece, Indoor and outdoor unit is already tested and comes with certificate and pipes are tested and comes with certificate so there is nothing to strength test.

OK, but only valid outside the EU.

[Peter_1]

Peter, my country is not in EU (and probably will not be) ..

Croatia is negotiating to join the EU, isn't it?

[nike123]

Croatia is negotiating to join the EU, isn't it?

Yes, but for now, that is at hold! And date of joining are continually postponing from mostly political reasons (and EU should stand for European economic union) and our goverment incompetence. At least, that is how I see it.

[brunstar]

it actually worries me about some of the work that is being carried out in different countries, i can see why a lot of countries have not changed to 410A either as i don't think the techs would be able to carry out the work.

If you are a fully qualified refrigeration engineer and have not been bred into it, the work to be carried out on installations should be of some similar quality, sealants and Co2 being used, hmm, if a strength test and leak test is not being carried out properly, i would hate to see what is going to happen when a VRV Co2 system is installed....hmmmm... i am scared and can see why there are so many leaks and problems out there and need for regulations!!!

[Peter_1]

A CO2 VRV, what's that?

[brunstar]

it is a Variable Refrigerant Volume, multi system running on CO2 gas.

[Peter_1]

What brands are already selling a CO2 VRV in the EU?
None I suppose.

[nike123]

I dont know is any in Europe.

Daikin: The global supplier is presenting a world premiere, as its latest VRV (Variable Refrigerant Volume) model is now using the natural refrigerant CO2. It is optimised for heating function. The outside unit features a heating capacity of 31.5 kW for heating, and 28 kW for cooling. Daikin has applied a new refrigeration cycle technology with a swing compressor and a newly developed heat exchanger. The CO2 model is compatible with all VRV control and management systems.

http://www.r744.com/articles/2008-10...2-(part-3).php

[john tucker]

you should only use OFN for this pressure testing

[Slatts]

you should only use OFN for this pressure testing

OK John. I'll bite. What's OFN?

[nike123]

OK John. I'll bite. What's OFN?

Oxygen Free Nitrogen

[Slatts]

Oxygen Free Nitrogen

Thanks nike.
Over here in my neck of the woods, we still use industrial dry nitro.