Leak on Airedale Close Control, Help!!

[Bash1803]

I have been called to a "leak" on an Airedale close control unit.
I have been told the system loses approx 1kg of R407C per week (holds 32kg).
The unit has been pressure tested with OFN (it held) then with Helium (it held), as a last attempt we tried a VAC test (it held).
The system has been injected with spectroline and apart from some tiny spots of green found on the evaporator coil passes, nothing.
I have stripped down the indoor & outdoor units and have also stripped off all the armaflex from the pipe work and still can't find anything!!!!! :(

Does anyone have any suggestions as I feel I have done everything I can??

[nike123]

I have been called to a "leak" on an Airedale close control unit.
I have been told the system loses approx 1kg of R407C per week (holds 32kg).
The unit has been pressure tested with OFN (it held) then with Helium (it held), as a last attempt we tried a VAC test (it held).
The system has been injected with spectroline and apart from some tiny spots of green found on the evaporator coil passes, nothing.
I have stripped down the indoor & outdoor units and have also stripped off all the armaflex from the pipe work and still can't find anything!!!!! :(

Does anyone have any suggestions as I feel I have done everything I can??


......................................

[Brian_UK]

Green spots seem to answer your search.

Try also changing the temperature of the pipework when testing, use a heat gun or similar. The expansion and contract can sometimes show up leaks.

[Bash1803]

Yeah possibly.
The green spots may be the RTU leak spray that was used by the previous engineer, i cleaned it and left it under pressure so only time will tell at the moment.
Also, for such a large amount of leakage (approx 1kg per week) I would have expected to find some oil, but there was none.

I was told that the fan speed controllers have a tendancy to leak aswell so i'm going to go back and have a sniff behind the covers...

Thanks for the reply though Brian, the guys in my company all seem to be baffled by this as 5 weeks have already been spent on this system!!!

[beagle]

The RTU "bubble up" crap should be easy to distinguish from the flourescent dye, the RTU stuff will go greenish in colour if left over a prolonged period but the dye should be a very vivid colour.

[superswill]

can you brake the system down into smaller sections to test,eg indoor/outdoor/suction/liquid line

[Bash1803]

can you brake the system down into smaller sections to test,eg indoor/outdoor/suction/liquid line


We have already done this with Indoor, Outdoor and Pipework seperated and it passed all pressure and VAC tests. We also stripped all of the Armaflex from the pipe work and tested the pipes and insulation for signs of spectroline and nothing!!

[nike123]

We have already done this with Indoor, Outdoor and Pipework seperated and it passed all pressure and VAC tests. We also stripped all of the Armaflex from the pipe work and tested the pipes and insulation for signs of spectroline and nothing!!

How long did you conducted pressure test?

[Bash1803]

A week for both times, the system as a whole and then again when it was seperated.

[marc5180]

I have just had the same problem as you, see following thread

http://www.refrigeration-engineer.com/forums/showthread.php?t=17755

We spent over 8 weeks on it and in the end it turned out to be a nail that had been rubbing against the pipework and over time had made a hole in the pipework.

When we pressure tested it, it must have somehow sealed itself because it did not show up a leak.

Just a few things that i tried;

Can you get access to all pipework? If so i suggest checking it all including joints,
Check around the compressor itself ( not just the stubs) because i have had them leak around the electrical box.

Check all around the coils, down the sides where the copper links through. On the top of the coil incase the fan mounting plate has been rubbing against the coil.

Any capillarys?

I know you have probably checked most of these but if not check them first.

[Bash1803]

Thanks very much Marc.
I'll run through the list but have a feeling we looked at most of this.

I appreciate the feedback.

[paulc1978]

check shut off valve caps they have to be very tight

[El Padre]

I think that you may have allready identified the most likely cause, have had loads of leaks on the Johnson controls fan speed controllers!

Cheers

[hyperion]

Check inside any pressure switches for leaks on the bellows. Welds on the feet/base of the compressors, but would have thought you would notice oil at these points. Have you tried nitrogen/hydrogen leak test. It is expensive but will often find leaks that nitrogen or helium cannot find. Speak to someone at Vulkan Lokring for more info.

[boulting]

Does the system have relief valves on it? they could be lifting for some reason and letting out your 1Kg a week, stick a balloon over the outlet.......just a thought :)

[El Padre]

Does the system have relief valves on it? they could be lifting for some reason and letting out your 1Kg a week, stick a balloon over the outlet.......just a thought :)

A condom also works well!:D

[thebigcheese]

all of the above plus when you are pressure testing are you leaving gauses on.
you may want to back seat valves incase the are only leaking when you have gauges removed

[Coolie]

Airedale shmaredale :eek:

A few further places to look:


Check the electrical cables coming from transducers. I've had it where the transducer diaphragm lets bye, but the refrigerant travels up the cable.
Porous pipework. Poor quality pipe can become porous over time, especially on bends!


good luck, and be sure to tell us when you find it!

[mad fridgie]

If you are leaving your gauges on during testing thenit could be as simple as a damaged service cap.
It sounds as if you have completed a thourgh test. Therefore is sound like a heat related leak. I would check your compressor post terminals. (when it has been running at normal temp)
Would of thought spectraline would of picked this up

[john.sikiotis]

If you have a 4way valve chevk there or in the inlet from the condeser.Sometimes when there is a turn in the inside it might be you have a leak.Anuway i would look at the high pressure side first!