Un-sticking TXV

charliechicago

Hello to all,
Does anyone have experience with this or any other similar product?
Looking to use it but the customer asked if it works and i've
never used it.
Thanks, Michael.
Its Nu-Calgon A/C Re-New

charliechicago

I tried to attach picture

ratio

No personal experience with that particular product, but the official cure for Copeland's li'l oil issue was a can of some kind of treatment; & that's the mfgr of the leak sealer that I've had the best results with (c. 50% no callback after one year).

Ironman

That's what Copeland recommends, and yes, it does work.

charliechicago

Thanks for the response. Does it work immediately to unstick?

pecmsg

Its better at keeping the replacement valve from sticking.

That issue was resolved what 3 - 5 years ago?
What makes you think thats your issue?

charliechicago

Pecmsg-
Ok, didn’t realize. Getting high head. Coil clean and not overcharged. Had one I posted about a couple of weeks ago and I changed the txv and it ran ok. This one is a spacepak that the txv is all soldered and all the handler is butted up against the attic slope and I don’t want to try and replace it. I rather replace the whole coil, which is quite expensive. So I thought it’s worth trying.

pecmsg

That’s your call I’m not there.

The last one you changed did you happen to look at the screen, take it apart?

ChrisJ

> @charliechicago said:
> Pecmsg-
> Ok, didn’t realize. Getting high head. Coil clean and not overcharged. Had one I posted about a couple of weeks ago and I changed the txv and it ran ok. This one is a spacepak that the txv is all soldered and all the handler is butted up against the attic slope and I don’t want to try and replace it. I rather replace the whole coil, which is quite expensive. So I thought it’s worth trying.

High head...... But what's your SH and SC?
The txv doesn't care what your head pressure is if the SH is correct.

pecmsg

Stuck TXV’s do not give high head.

Ironman

charliechicago said:

Pecmsg-

Ok, didn’t realize. Getting high head. Coil clean and not overcharged. Had one I posted about a couple of weeks ago and I changed the txv and it ran ok. This one is a spacepak that the txv is all soldered and all the handler is butted up against the attic slope and I don’t want to try and replace it. I rather replace the whole coil, which is quite expensive. So I thought it’s worth trying.

I agree that the high head pressure is likely do to something else.

How old is the system? Is the condensing unit a micro chanel?

charliechicago

It’s about ten years old, but the condensing unit was replaced the beginning of last summer. It’s not a micro channel. No temp drop across the filter drier. I’m getting a super high subcool. Around 60. The head goes up to 600 psi. And sometimes it will all of a sudden drop to 500psi If the txv is stuck closed that could give me a high head with high subcool and bouncing around I figure. The suction pressure does not pull down thought, so maybe some refrigerant is getting though I thought.

ChrisJ

> @charliechicago said:
> It’s about ten years old, but the condensing unit was replaced the beginning of last summer. It’s not a micro channel. No temp drop across the filter drier. I’m getting a super high subcool. Around 60. The head goes up to 600 psi. And sometimes it will all of a sudden drop to 500psi If the txv is stuck closed that could give me a high head with high subcool and bouncing around I figure. The suction pressure does not pull down thought, so maybe some refrigerant is getting though I thought.

If both liquid and suction pressures are high .....

pecmsg

Have you weighed in the charge?

Ironman

It sounds like it's over-charged. What's the superheat? Does it get high when the head pressure goes up?

heathead

Chris,

You say both liquid and suction pressures are high. I had a bad txv it was clogged / stuck, that was r-22 that both the liquid and suction where both very high copeland scroll about ten years old. Still can't figure out in my head how they both climbed at the same time so high. Was many years ago so i don't remember specifics. I know I changed txv and it fixed the problem. I like to know why and not just change parts but it worked, but couldn't figure out why they both climbed so high so fast. I would love two know how they both climbed high at the same time so fast. Logic behind it? I can't picture it in my mind as to why they both climbed up in pressure. Can someone post the copelands tech buliten on the oil fix or additive? Thanks

ChrisJ

> @heathead said:
> Chris,
>
> You say both liquid and suction pressures are high. I had a bad txv it was clogged / stuck, that was r-22 that both the liquid and suction where both very high copeland scroll about ten years old. Still can't figure out in my head how they both climbed at the same time so high. Was many years ago so i don't remember specifics. I know I changed txv and it fixed the problem. I like to know why and not just change parts but it worked, but couldn't figure out why they both climbed so high so fast. I would love two know how they both climbed high at the same time so fast. Logic behind it? I can't picture it in my mind as to why they both climbed up in pressure. Can someone post the copelands tech buliten on the oil fix or additive? Thanks

When you changed the valve did you just pump down or recover and then charge by weight?

The subcooling can climb while superheat climbs.
But both suction and liquid pressures cannot climb at least not the way I see it.

mattmia2

ChrisJ said:

> @heathead said:

> Chris,

>

> You say both liquid and suction pressures are high. I had a bad txv it was clogged / stuck, that was r-22 that both the liquid and suction where both very high copeland scroll about ten years old. Still can't figure out in my head how they both climbed at the same time so high. Was many years ago so i don't remember specifics. I know I changed txv and it fixed the problem. I like to know why and not just change parts but it worked, but couldn't figure out why they both climbed so high so fast. I would love two know how they both climbed high at the same time so fast. Logic behind it? I can't picture it in my mind as to why they both climbed up in pressure. Can someone post the copelands tech buliten on the oil fix or additive? Thanks



When you changed the valve did you just pump down or recover and then charge by weight?



The subcooling can climb while superheat climbs.

But both suction and liquid pressures cannot climb at least not the way I see it.

They can if something is closed or blocked between the suction port and the the inlet of the compressor like say the service valve.

ChrisJ

mattmia2 said:

ChrisJ said:

> @heathead said:

> Chris,

>

> You say both liquid and suction pressures are high. I had a bad txv it was clogged / stuck, that was r-22 that both the liquid and suction where both very high copeland scroll about ten years old. Still can't figure out in my head how they both climbed at the same time so high. Was many years ago so i don't remember specifics. I know I changed txv and it fixed the problem. I like to know why and not just change parts but it worked, but couldn't figure out why they both climbed so high so fast. I would love two know how they both climbed high at the same time so fast. Logic behind it? I can't picture it in my mind as to why they both climbed up in pressure. Can someone post the copelands tech buliten on the oil fix or additive? Thanks



When you changed the valve did you just pump down or recover and then charge by weight?



The subcooling can climb while superheat climbs.

But both suction and liquid pressures cannot climb at least not the way I see it.

They can if something is closed or blocked between the suction port and the the inlet of the compressor like say the service valve.

Wow.
That's a good point.

heathead

I recovered then charged by weight. Both pressures where climbing. Trying to picture something blocked between suction port and inlet of compressor. Just replaced txv, replaced dryer on liquid side, nitrogen flowing when brazing then vac down below 500 for 30 min. It does have a high pitch noise on shut down sometimes, sounds like Freon going thought a check plate /valve when pressure equalizing. Wonder if its worth the treatment. Its copeland scroll about 10 year old seer 13 or 14 with ecm extended fan time. I will try and google for bulletin on copeland scroll.

ratio

What's the outdoor fan doing at this time? Approach temp or liquid line temp?

Ironman

mattmia2 said:

ChrisJ said:

> @heathead said:

> Chris,

>

> You say both liquid and suction pressures are high. I had a bad txv it was clogged / stuck, that was r-22 that both the liquid and suction where both very high copeland scroll about ten years old. Still can't figure out in my head how they both climbed at the same time so high. Was many years ago so i don't remember specifics. I know I changed txv and it fixed the problem. I like to know why and not just change parts but it worked, but couldn't figure out why they both climbed so high so fast. I would love two know how they both climbed high at the same time so fast. Logic behind it? I can't picture it in my mind as to why they both climbed up in pressure. Can someone post the copelands tech buliten on the oil fix or additive? Thanks



When you changed the valve did you just pump down or recover and then charge by weight?



The subcooling can climb while superheat climbs.

But both suction and liquid pressures cannot climb at least not the way I see it.

They can if something is closed or blocked between the suction port and the the inlet of the compressor like say the service valve.

I can't quite agree here: if there was a blockage between the suction port and the compressor, the head pressure would begin to go down since the compressor would be pumping little or nothing into the condenser coil as the fan was cooling it.

Ironman

@charliechicago,
Assuming that there's nothing dumping excessive heat into the evaporator (like a hot water coil before it), then the only other thing that could cause both suction and head pressures to be too high is an over-charge of refrigerant. A stuck TXV won't do that. It would starve the evaporator and the suction pressure would then be too low and the superheat would be too high.

mattmia2

Ironman said:

mattmia2 said:

ChrisJ said:

> @heathead said:

> Chris,

>

> You say both liquid and suction pressures are high. I had a bad txv it was clogged / stuck, that was r-22 that both the liquid and suction where both very high copeland scroll about ten years old. Still can't figure out in my head how they both climbed at the same time so high. Was many years ago so i don't remember specifics. I know I changed txv and it fixed the problem. I like to know why and not just change parts but it worked, but couldn't figure out why they both climbed so high so fast. I would love two know how they both climbed high at the same time so fast. Logic behind it? I can't picture it in my mind as to why they both climbed up in pressure. Can someone post the copelands tech buliten on the oil fix or additive? Thanks



When you changed the valve did you just pump down or recover and then charge by weight?



The subcooling can climb while superheat climbs.

But both suction and liquid pressures cannot climb at least not the way I see it.

They can if something is closed or blocked between the suction port and the the inlet of the compressor like say the service valve.

I can't quite agree here: if there was a blockage between the suction port and the compressor, the head pressure would begin to go down since the compressor would be pumping little or nothing into the condenser coil as the fan was cooling it.

The suction pressure would be higher than normal, the liquid pressure would be lower than normal and they would likely be equal. I don't see anything other than that or an overcharge that would cause the suction pressure to rise. i suppose a lack of heat load on the evaporator would do something similar.

EBEBRATT-Ed

Sounds to me like the internal bypass in the compressor is passing gas. maybe overcharged and blowing gas discharge to suction

One of the best tools is an amprobe, tells you weather the compressor is loaded or just spinning. How are the compressor amps?

JUGHNE

Ed, yes if the internal bypass is stuck open and then more gas was added to bring up the discharge pressure.
You can usually definitely hear it open.
They do not always reset.

ratio

If you're hitting 600#, I'd expect the internal bypass to open, that'd be a hissing internal to the compressor, that may continue for a little while after the compressor stops.

You said you weighted in the charge, how did you calculate that? Also, virgin refrigerant? Might be non-condensables in there. I tried to run a split on N₂ once. It didn't go well.

ChrisJ

> @ratio said:
> If you're hitting 600#, I'd expect the internal bypass to open, that'd be a hissing internal to the compressor, that may continue for a little while after the compressor stops.
>
> You said you weighted in the charge, how did you calculate that? Also, virgin refrigerant? Might be non-condensables in there. I tried to run a split on N2 once. It didn't go well.

I'm no expert but I'm thinking you need a little more than a type L copper lineset and aluminum coil for that.

JUGHNE

I think you need a serious compressor set up to get nitrogen into liquid. But if you did it would be some serious cold. Don't put your hand into it.
It is used here for AI units.

ratio

Yeah, I was second on the job. It was a change out, the valves were open & there was pressure on the system, so I assumed that it was juice in it. I was wrong.

On the bright side, it had no leaks, & worked fine once I vac'd & charged it.