R407c pressure testing

[flash]

Hi Guys urgent help needed. I have a customer who we have moved a denco 407c system for now the sites H&S man is wanting a 35 bar pressure test. Our gauges only reach 34? I am sure that pressure is not required but cannot find anywere that states a reccommended test pressure- any idea's :)

[NoNickName]

The PED directive, if I remember well, states that the pressure test must be done at 1.2 times the service pressure. If PS = 29, then test pressure is 35bar. Your customer is perfectly right.

From a metrological point of view, a 35 bar gauge cannot be used for measuring 35 bar.

[thisname]

See BS EN 378 - Refrigeration and heat pumps - safety and environmental requirements - Section 2

[thisname]

Ps is the allowable pressure.

High side Ps is the refrigerant type at 55 deg C in the UK.

Leakage test pressure should be less than or equal to 1.3 time Ps.

[The Viking]

Hmm,
Don't forget to ask the manufacturer what the maximum allowed test pressure is.
Even if you only talking about a condensor, you might find that fanspeed controllers and other things attached not will allow for 35bar test pressure.

[koel goeroe]

Ps is the allowable pressure.

High side Ps is the refrigerant type at 55 deg C in the UK.

Leakage test pressure should be less than or equal to 1.3 time Ps.

Hi thisname,

Should we not make a difference between pressure test and leakage test?
By law we use the 1.3 time Ps for the pressure test. This is to see if the system can stand that pressure without distortion or even ripping open.
But does the law talk about leakage test at a certain value?

[NoNickName]

Sorry, I meant PRESSURE TEST, not LEAKAGE test. My mistake. The law simply states there should be no leakage in excess of 5 gr/year, whatever pressure.

[koel goeroe]

Sorry, I meant PRESSURE TEST, not LEAKAGE test. My mistake. The law simply states there should be no leakage in excess of 5 gr/year, whatever pressure.

You don't need apologizing because you have not mentioned leakage testing.
And yes indeed, NO leakages should be found in refrigeration systems.
BUT!!! Be aware!!
If unit has had a pressure test and during the pressure test the surrounding temperatures have risen, it does NOT guarantee you that the system is leak tight!!
I experienced the nitrogen pressure going up in a system during a pressure test while I visualised 3 pinhole leaks in the pipe plate of the tube & shell evaporator!!

[zenen]

so if the normal working pressure at HP side is 24bar at 40 celcius, then the pressure test will be ??

thanks

Z

[nike123]

http://i54.tinypic.com/s49ks6.jpg
http://i55.tinypic.com/124v42v.jpg

So, if your ambient never cross 38°C your design pressure is at 59°C saturation temp if you use air cooled condenser.
For R407C that is 27,7 bar gauge saturated liquid.
27,7x1,3=36 barg
27,7x1,1=30,5 barg

Your strength test pressure should be in between 30,4 and 36 barg.

If your ambient is above that and below 43°C your design pressure is at 63°C saturation.
For R407C that is 30 bar gauge saturated liquid.
Strenght test pressure will be from 33 to 39 barg.

And so on.....

[RatsPom]

Why not look on the manufacturers data plate or contact the manufacturer and ask what it is ?

[chillerman2006]

Why not look on the manufacturers data plate or contact the manufacturer and ask what it is ?

Exactly...and dont forget to check max pressure for low side

[Denco Technical]

http://i54.tinypic.com/s49ks6.jpg
http://i55.tinypic.com/124v42v.jpg

So, if your ambient never cross 38°C your design pressure is at 59°C saturation temp if you use air cooled condenser.
For R407C that is 27,7 bar gauge saturated liquid.
27,7x1,3=36 barg
27,7x1,1=30,5 barg

Your strength test pressure should be in between 30,4 and 36 barg.

If your ambient is above that and below 43°C your design pressure is at 63°C saturation.
For R407C that is 30 bar gauge saturated liquid.
Strenght test pressure will be from 33 to 39 barg.

And so on.....


The above quote is correct, however we advise you to remove HP/LP switches and any auxiliary connections (transducers etc etc)

[Tony]

BS EN 378:2008 states that the strength test should be carried out between 1.1 X Ps and 1.43 X Ps

[install monkey]

by the age of this post it should be up and running by now.by the way you can only pressure test upto the manufacturers data.testing with helium or leaving the test for a longer duration.

[chillerman2006]

by the age of this post it should be up and running by now.

lmao.. i gotta learn to check op dates