Changing trv on a live system

DP

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Older Danfoss trv with female nut/ reducer with 8mm pipe feeding the radiator. Pipe is to be fitted with a 15x8 yorky reducer to ensure long term leak free termination.

While radiator side work is no sweat, cannot figure how the pipe connections and alterations, along with removal of old fitting can be undertaken while pipe/ system is dribbling or running. Throw into the equation carpets which the customer certainly does not want marked, ruined or damaged.

Have challenged the poster who said it can be done but he chooses to stay quiet, perhaps can think how it can be done but in real life it is a different matter.

Saw the video on YouTube as suggested but right from the start there are errors that a pro would or should not make. There are jobs that are straightforward which any Diyer can undertake, then there are jobs that the Diyer is in hot water and has to step back and get rescued on.
 
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YouTube is your friend.

Have a look at the video posted in "that" thread where a plumber changes the pump and valves on a live system.

Bung up the tank and vents.
I remove the head of the tank and expansion pipe into a bucket when doing this. helps me clean the snot out of the tank
I then reuse the treated water to refil (with some filtering obviously).

Close the valves in the rad. Using an old lockshield valve, slacken off the side you want to replace, but take any pressure out of the rad with the bleed nipple 1st.

Once slackened off, the rad will glug strongly until the pressure eases. Use a bucket to keep the water for later.
Pull the rad valve off the rad, quickly reolacing it with the spare lockshield.
Close tight and make clean and clear.

Move into the new valve to be fitted.
Make sure everything is set out uncrewed and ready to go. Use lots of big towels.


Slacken nut on supply side of existing valve. Just so. Not tight still but...

Open valve to relieve most of the remaining head on the upstream side. You can close any valve in the system you can find here to help you (pumps etc,) won't stop the flow but might slow it down.

Depending on the static pressures etc, this is the exciting bit.

Push down in the old valve to push the valve against the olive. Unscrew valve. With the flow from the open valve at a reasonable low, quickly, switch the new valve over.

Clean up and tighten up.

Worked for me for most of my system as i didn't know where my drain off point was at the time (i didn't have one. The plumber thought better).

I did get caught out once though as i had to go for a **** mid swap and forgot to release the static pressure which had built up.

If you are struggling to stop the head, there are pipe freezing kits available in most DIY shops. €20 but should do a few rads.

Best of luck
 

DP

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quickly, switch the new valve over.

If the cap nut has the same thread etc. But the fitting on the old trv is wrong pattern, wrong thread and pipe needs an adapter as the valve is 15mm and pipe is 8mm. I chose not to use compression adapter, used solder ring fitting. Water constantly discharging from the pipe will not allow soldering.
 
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i would imagine he is going to bung it or its a sealed system
 
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1a) Abusive or unhelpful posts are not welcome on this site and are always removed!

To BlueLoo

Some of your posts go beyond Abusive or unhelpful as they are giving dangerous advice to people seeking help.

Where have a given advice, not opinion and when has it been dangerous?
 
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How is that relevant to the post?

This thread and your attitude breaks most of the rules in it.

The rules dont seem to be applied linearly on this forum so carry on...
 
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Where have a given advice, not opinion and when has it been dangerous?

Push down in the old valve to push the valve against the olive. Unscrew valve. With the flow from the open valve at a reasonable low, quickly, switch the new valve over.

If you are struggling to stop the head, there are pipe freezing kits available in most DIY shops. €20 but should do a few rads.

when the quick switch over doesn't go as quickly as planned then what happens to the water while you nip off to get the pipe freezing kit.

STOP giving writing stupid comments and STOP giving hazardous badvice on this forum.
 
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