expansion valve repairs

[philjd26]

hi
what is involved in changing a valves power assembly? also reading through posts and recommends replacing cage?? whats this and whats involved?

just wondering if replacing these parts will save me the hassle of brazing a hole new valve in...

rgrds phil

[al]

phil

you can replace the head seperately and the orifice cage, leave the body in place. beware that some older bodies had filters on the inlet,(although maybe only yorks!!)

Whats wrong with existing valve?

al

[philjd26]

hi al

thats grand..!! saves me hassle, its an alco trx-n14 in a technair ccu. 407c..

basically getting 13brg liquid pressure behind valve, with no temp drop across liquid line drier...back pressure is at 10 psi absolute and fully charged...

had a look at the new valve inlet...and there is no strainer...id imagine dodgy valve is the same...

rgrd phil

[Brian_UK]

I do like the way we mix our numbers....

13 barg on one side and 10 psia on the other.

Take some cleaning rags or similar with you, I have had old TEVs full of crap due to bad install. Although strainers were not to bad the cage was really yuk. Otherwise, a simple job - don't play with the new cage, check the setting is correct for the gas/duty but don't rotate it unless you have to.

[philjd26]

for consistency 205psia/10psia....

[philjd26]

can i change power assembly without recovering ref..?????

[nike123]

can i change power assembly without recovering ref..?????

Yes you could, if it is leaked out before!

If you have receiver and isolation valves at right place, you could pull refrigerant in receiver with compressor and isolate it. Then you could evacuate small amount remained refrigerant in that part of system very quickly.

[al]

phil

once you undo the bolts you're at liquid line pressure,so yes recover if you can't pump down. Give me a pm if you want.

al

[philjd26]

hi

update on the valve....had to chage the hole lot.ie valve and drier...found the LL core drier had broke down and bloked the exp valve...

anyone come acroos this before??? any thing else i should look out for as i can imagine there are still bits of the core still in there....

rgrds phil

[al]

have seen it on older yorks especially when the cores are replaced and reassembled wrong.

al

[Brian_UK]

High temperatures can destroy driers sometimes.

[Kaiser]

Yep, had a drier break down and blocked the TX. Blew thru with nitro and changed drier, fortunately all ok.