Bad TXV ? or solenoid valve?

[kurt s]

i have a AC unit around not sure of tons but i would guess 15 ton, runs on R22..... it has 1 compressor but 2 stages at the evap. coil.

each 1/2 of coil has its own TXV and a solenoid valve just before the TXV.

i am getting flow and cooling through the 2nd stage of coils, The solenoid valve is opening and the txv is operating.

But the 1st stage is doing nothing, i have power 24v to solenoid and the magnet is working but im not sure its opening, there is a manual screw on the bottom of the solenoid valve that i screwed all the way in to force it open, still nothing........

could it still be the solenoid it stuck shut? or is my TXV not operating? and staying shut???

[tonyelian]

hi
you should start from the filter drier may be restriction is there.
about solenoid valve when its energized you should hear a click .

[Magoo]

Hi Kurt S
if the power element on the TXV looses its charge it will shut the TXV down, zip zero flow.

[Tesla]

Hi Kurt
I think Magoo is right - the TXV blocked or element has lost charge. If you have a conventional solanoid valve you could use a permanent magnet to check. I have had one that would click but didn't open til I put on the magnet which kept a chiller going until I got a new solanoid valve. Considering there should be only one drier and the other circuit is flowing. If there was a little flow at start up it would suggest moisture in the system. I would simply replace the drier and TXV.

[chemi-cool]

I would disconnect the working circuit and check if the suction pressure increases when SV energize.
Filter in the TXV entrance should be checked too.
If nothing work, start with replacing the TXV, SV does not have as many problems as TXV.

Basically I am with Magoo direction.

[kurt s]

thanks for the responses ill keep you updated, the SV has a manual screw for a bypass on the bottom i also tried and still nothing. i assume its the txv, i will take it apart and find out next week.

as for the dryer it is just before both of the valves as TESLA mentioned so that is not the problem.

thanks so far, im sure it will get worse before it gets better.

[Royal241]

Did you find the second compressor?

[kurt s]

Royal241

Re: Bad TXV ? or solenoid valve?
Did you find the second compressor?




not yet yet what do they look like?

for anyone else interested (that actually cares) ill keep you updated. going to have to wait 2 weeks for new txv..... and new toy http://store.cyberweld.com/smqutwtip.html

[Magoo]

Hi Kurt.
with most TXV's Danfoss Sporlan Alco, you can purchase the power element assembly as an individual item. Probably too late if you have ordered a total new TXV.
Keep us informed with results though.

[kurt s]

i installed the new tev and its working much better, is changing the power head easy to do? the old one looked like it was brazed to the top of the valve body.

[HVACRsaurus]

Not all power heads are replaceable. If they are replaceable they are usually screwed on and you will see the flats for getting your spanners on, yours probably a sealed unit. Thanks for posting the outcome, always good to find out end result!