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seanf
19-05-2017, 09:41 PM
Not familiar with why you would put a rubber boot on an expansion valve. Seen a few of them mainly on Carrier units, not tightly fitted and is open at the top. I would have though it would cause problems with trapping moisture. Anyone know what there for?

Thanks

14809

FaultCode
19-05-2017, 10:20 PM
Probably trying to keep the head warmer than the bulb do that the charge does not migrate to the head.

Glenn Moore
19-05-2017, 10:30 PM
Hi Sean
sometimes it is necessary to cover the stainless steel capillary tube to try to prevent corrosion caused by chlorine. This can be necessary in certain enviroments such as swimming pools , where fish are stored (sea water) etc . I have seen a number of these T2 valve which have lost the charge due what is termed as deep crevice corrosion.
What product is stored close to the valve .?.
The blackening of the brass body is indicative of an aggressive enviroment

seanf
20-05-2017, 10:34 AM
Hi FaultCode,

Its open at the top so the top of the head is visible.

Thanks

Grizzly
20-05-2017, 10:38 AM
Brilliant answer Glenn.
You learn something new every day.
Grizzly

seanf
20-05-2017, 10:58 AM
Hi Glenn,

As far as I know its just a standard Carrier unit on a box van for moving meat products, it may be that they use a cleaning product for the back of the van. The only reason I could think of was to try and protect against corrosion at the joint on the diaphragm, but the boot is open at the top and I would have thought moisture would be more likely to collect and then get between the boot and the diaphragm and cause more of a problem. The boot has a bit of height so could create a pocket of stagnant air.

Thanks

monkey spanners
20-05-2017, 01:11 PM
Maybe its to stop the capillary vibrating and rubbing through, i usually put two or three small cable ties on the loop of capillary to stop unwanted movement.

seanf
20-05-2017, 01:31 PM
Maybe its to stop the capillary vibrating and rubbing through, i usually put two or three small cable ties on the loop of capillary to stop unwanted movement.
Think youve probably got it monkey spanners.

14813
Maybe a better image than the first. It does look like the capillary is held by the boot, but I would have thought it would be better to prevent moisture being trapped and just use cable ties.

Thanks

cadwaladr
20-05-2017, 09:04 PM
I think it's to stop vibration,it's always like that on carrier road units

Glenn Moore
20-05-2017, 10:26 PM
Hi Sean
It is certainly an overkill but there again being banged around on our potholed roads and vibrations from a Diesel engine perhaps they deem it necessary to prevent capillary tube damage, it's certainly a neat idea, looks a bit like shrink tubing. But as you quite rightly say it would be better to keep the capillary tube in a dry condition than to keep it submerged in some possibly aggressive fluid which will shorten its life cycle. I used to use cable ties the same as monkey spanners more for neatness than anti vibration but even using cable ties can contribute to corrosion failure under the right circumstances which I had on some trawlers up in your kneck of the woods. Most engineers assume that stainless steel will last for years inmany cases it does , but under certain environments it can be corroded as easily as mild steel unless precautions are taken.

RANGER1
20-05-2017, 10:37 PM
Just to add, If you use cable ties only, capillary to power element could still bounce around breaking it, unless most of it was supported by securing it to something else.
I guess it looks professional as well.

charlie patt
21-05-2017, 06:14 PM
Carrier introduced them on xarious and 30 to stop capillary bouncing and vibrating on servicein when in warranty we where requested to spray with white grease to protect capillary lot of these vans where on fish and rotted them out

cadwaladr
22-05-2017, 12:20 AM
Transport units suffer from extreme vibration as said before in earlier posts I used to wrap them around the head and use insulating tape if you did not they would just not last,quite a weak spot with the danfoss valve,the stresses and strains on transport refrigeration is like drinking a pint on a bike with a buckled wheel !!!!