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-   -   BS or not? (http://www.diychatroom.com/f17/bs-not-149030/)

raylo32 07-03-2012 11:16 AM

BS or not?
 
Friend of mine had a new Trane system (100k gas furnace, variable speed 2 stage A/C condenser and coil) installed last summer. They recently had some problems and the tech diagnosed it as a failing TXV throttling down too much causing coil icing.

HVAC company ordered the new TXV and the tech came out to install it and the guy's wife said he did the entire job in a half hour. So in 30 minutes he supposedly pumped the system down (even possible with a failing TXV?), removed the old TXV, brazed in the new one, evacuated the system and brought it back in service. Did he have time to do a Nitrogen purge or pull a proper deep vacuum, check/adjust the charge? Sounds like a fish story to me... or just a very rushed and potentially shoddy job?

Marty S. 07-03-2012 11:30 AM

I couldn't do it in a half hour. More like 1.5 hours.

JJboy 07-03-2012 12:50 PM

Big BS.

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beenthere 07-03-2012 05:30 PM

First. Is it a TXV that brazed in, or was it a screw on TXV? I can do a screw on in 30 minutes if I have easy access to the coil/TXV.

Done right, you don't need to vacuum the system after changing the TXV.

raylo32 07-03-2012 07:21 PM

He said that the tech told him that maybe the original TXV had been damaged during install due to excessive heat from brazing, so I assume the replacement had to be brazed in. My friend is not very up on HVAC stuff and I have not seen inside the coil box myself. He said the system is working fine and he is happy, which is all that really matters I suppose.

stickboy1375 07-03-2012 08:41 PM

Quote:

Originally Posted by raylo32 (Post 957227)
He said that the tech told him that maybe the original TXV had been damaged during install due to excessive heat from brazing, so I assume the replacement had to be brazed in. My friend is not very up on HVAC stuff and I have not seen inside the coil box myself. He said the system is working fine and he is happy, which is all that really matters I suppose.

Did this cost him anything or under warranty?
If it didn't cost him anything, I really don't think it matters what they told the owner.

Missouri Bound 07-03-2012 10:36 PM

Quote:

Originally Posted by stickboy1375 (Post 957284)
Did this cost him anything or under warranty?
If it didn't cost him anything, I really don't think it matters what they told the owner.

I can't agree. If a service tech lies to the owner, it DOES matter. :yes:

beenthere 07-04-2012 04:16 AM

Quote:

Originally Posted by raylo32 (Post 957227)
He said that the tech told him that maybe the original TXV had been damaged during install due to excessive heat from brazing, so I assume the replacement had to be brazed in. My friend is not very up on HVAC stuff and I have not seen inside the coil box myself. He said the system is working fine and he is happy, which is all that really matters I suppose.

Weather a screw on or a brazed in TXV. Its powerhead is still strapped to the vapor line. Its possible the powerhead was over heated when the vapor line was brazed to the coil.

Very few residential TXVs are braze TXVs.

raylo32 07-04-2012 06:32 AM

Yes, repaired under warranty but apparently just barely so. He thought the TXV warranty was only one year?? Yikes.

Part of the problem figuring this out is that this is all third hand info from folks that aren't conversant with HVAC terms. They aren't quite sure exactly what was done except that the TXV was replaced.

I suspect BT is correct that it was a screw on TXV. Still doesn't leave a lot of time for pulling vacuum but maybe enough with one of your commercial duty vac pumps and since the system wasn't really open for long.

beenthere 07-04-2012 06:51 AM

Quote:

Originally Posted by raylo32 (Post 957515)
Yes, repaired under warranty but apparently just barely so. He thought the TXV warranty was only one year?? Yikes.

Part of the problem figuring this out is that this is all third hand info from folks that aren't conversant with HVAC terms. They aren't quite sure exactly what was done except that the TXV was replaced.

I suspect BT is correct that it was a screw on TXV. Still doesn't leave a lot of time for pulling vacuum but maybe enough with one of your commercial duty vac pumps and since the system wasn't really open for long.

There is a way to change it out that a vacuum is not needed.

Also, they may have only changed out the powerhead, which takes very little time.

biggles 07-04-2012 06:56 AM

the TXV might of had no SH adjusting stem and or the power element/cap tube itself was shot.to do it all in 30 minutes possible if he had a helper, but pump down, torch in the basement then do vacs out on the condenser :no: and if it was warrenty he has the hours OK'd by the factory to cover it why rush.it's not brain surgery for a seasoned tech,but it would take him 30 minutes just to get all his stuff out and back into the truck for sure....did somebody actually hear or smell a torch being used?:wink:if it was just a power head flip he could pump down to 5psi and flip the HAT under pressure down on the evap section usually outside the air side.so no vac or nitro required....:whistling2: reopens the LL and suction valves out on the condenser and your good to go.


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