TXV body frosting over

[iraqveteran]

Haven't seen a thread on this topic in a while. So just to refresh my memory...

I have to do a re-check on a walk-in tomorrow that our on-call tech had to work on this past Friday.

He had to replace the temp control.........no big deal there...........but....


He noticed that there is frost/ice accumulation on the body of 1 TXV. He wasn't too specific on whether it was frost or a freeze. This is a large walk-in cooler, 1 condenser and 2 evap coils in the box. R-22 refrigerant. There has been no repairs made to this walk-in to my knowledge within the last year...


I can't for the life of me remember the model of the equipment.......brain fart :rolleyes:...



So what are ALL the possible causes of the valve body frosting/freezing over?

[jwc64]

Haven't seen a thread on this topic in a while. So just to refresh my memory...

I have to do a re-check on a walk-in tomorrow that our on-call tech had to work on this past Friday.

He had to replace the temp control.........no big deal there...........but....


He noticed that there is frost/ice accumulation on the body of 1 TXV. He wasn't too specific on whether it was frost or a freeze. This is a large walk-in cooler, 1 condenser and 2 evap coils in the box. R-22 refrigerant. There has been no repairs made to this walk-in to my knowledge within the last year...



I can't for the life of me remember the model of the equipment.......brain fart :rolleyes:...



So what are ALL the possible causes of the valve body frosting/freezing over?

Restricted flow.

Plugged inlet screen
Out of adjustment.
Weak power head.

[iraqveteran]

Restricted flow.

Plugged inlet screen
Out of adjustment.
Weak power head.

And a plugged inlet screen would cause flashing the valve body...


So, provided the filter dryer is doing its job, a significant temp drop across it would be a good indicator....


I'm also thinking maybe the solenoid could be weak causing the refrigerant to be metering at the solenoid as apposed to the TXV.

[Dchappa21]

And a plugged inlet screen would cause flashing the valve body...


So, provided the filter dryer is doing its job, a significant temp drop across it would be a good indicator....


I'm also thinking maybe the solenoid could be weak causing the refrigerant to be metering at the solenoid as apposed to the TXV.


Yep pump it down and clean or replace the screen.... I keep new ones in my truck and just replace them and clean the old one up for use later.

[iraqveteran]

Yep pump it down and clean or replace the screen.... I keep new ones in my truck and just replace them and clean the old one up for use later.

not a bad idea...


I don't have any spare screens on my truck but I may have a few extra expansion valves somewhere in there....I may be able to cannibalize one for this project. I will be on a time limit on this job....gotta be in and out in under 2 hours.

[icemeister]

Get a can of CRC Brakleen to clean up TEV screens....and lots of other stuff.

No mess, no residue, no problem.

[skwsproul]

not a bad idea...


I don't have any spare screens on my truck but I may have a few extra expansion valves somewhere in there....I may be able to cannibalize one for this project. I will be on a time limit on this job....gotta be in and out in under 2 hours.
Ouch that may not be enough time. Who gave you this time limit? I would explain that it may not be enough time. If you get lucky and the system is small enough and the solenoid valve holds and the strainer is dirty and the txv is set correctly and the sytem charge is spot on and so forth and so on, you will fix it in 2 hours or less.

Time limits and quality work do not work hand in hand when there are uknown factors involved.

[crackertech]

Get a can of CRC Brakleen to clean up TEV screens....and lots of other stuff.

No mess, no residue, no problem.
That's some good stuff.:)

[crackertech]

Restricted flow.

Plugged inlet screen
Out of adjustment.
Weak power head.

push pins stuck.

[jwc64]

Ouch that may not be enough time. Who gave you this time limit? I would explain that it may not be enough time. If you get lucky and the system is small enough and the solenoid valve holds and the strainer is dirty and the txv is set correctly and the sytem charge is spot on and so forth and so on, you will fix it in 2 hours or less.

Time limits and quality work do not work hand in hand when there are uknown factors involved.

No doubt. Best case scenario is the plugged inlet screen. Some of the other stuff is more time consuming. And like cracker said, sticking push pins may mean burning in new valve.

[iraqveteran]

There is no real time limit.....


The manager at this place is the worst one we have. I would be more than happy if this account goes belly up and we don't gotta deal with her anymore....


Tomorrow is gonna be a waste of time I'm sure. The cooler will come down to temp and hold steady. There is no problem with that.....


She just wants a "second opinion" from another tech....its just how she is, you gotta tell the b!tch 5 times whats wrong and why before she will believe anyone. The use of big words and technical terms is a must. Baiscally I gotta use terminology that confuses her.....if she hears the same thing from 3-5 different techs, then she will believe us. But I highly doubt she will approve any repairs to be made until the box won't hold temp.....and then she'll b!tch about the cost of repairs when more extensive damage is done....


Its job security, thats for sure. Its just a waste of time for me....I got 2 calls already tomorrow and they aint nothin but re-checks from this past holiday weekend......waste of time IMO. I would rather get a jump start on this months PM list with Christmas fastly approaching....

[Dowadudda]

you know, I have been using KO Blaster. I like to stock this on the truck anyways for singles. The stuff works really good for plugged screens.

[Slatts]

check that the external equalizer line isn't iced up. If it is then the pin seal is shot and the valve will have to go.
I've seen this where the external eq. line is piped in on the evap side of the TEV bulb.
It squirts liquid into the suction line up stream of the bulb, chilling it right down and causes the valve to close down. That's why we always put the bulb on the evap side of the equalizer line hey.

[jpsmith1cm]

you know, I have been using KO Blaster. I like to stock this on the truck anyways for singles. The stuff works really good for plugged screens.

KO blaster is awesome stuff.

Just be careful around paint!!

[iraqveteran]

Just like I told yall......


waste of my time. spent 2 hours there, ran up their bill nicely and got denied making any repairs to the walk-in......


oh well, not that I care. She knows whats going on and she knows that come a Friday night, she will have no excuses as to why she shouldn't pay overtime rates.

[GGALLAND]

Yes the txv frosting is definately the result of a massive pressure drop. I'd check the powerhead first, make sure the cap tube is'nt broken.

[mark itziro]

TXV frosting/freezing reasons... low on gas?

[fitter33]

TXV frosting/freezing reasons... low on gas?

Not if it's just 1 TXV, unless of course it is the last circuit and last case on the Rack....LOL....can be tricky sometimes.

...the screen or liq. line drier in the case will most probably be the issue. If the drier has a temp. diff. cut it out. Don't worry about replacing it, the cores at the Rack are all you need.