Leaky E.C.A. TRV

[steven.french]

I discovered last night that the TRV on our hallway radiator has been dripping for quite some time. Is there anything I can tighten? It's an ECA and looks like this:

I see in other threads people suggesting tightening the nut surrounding the pin, but I have no idea how to remove the plastic bit. Can anyone help?

 

[Whitespirit66]

Where's it leaking from? Under the head, or the compression nut? You need to undo the chrome nurled ring to inspect under head. Turn it anti-clockwise looking end-on to the head - mole grips or pump pliers are ideal if tight.

Though if it is leaking from under head, best to replace. Not very expensive.

 

[Armo74]

To remove the head you have to unscrew the plastic knurled nut under earn the TRV head.

 

[steven.french]

Where's it leaking from? Under the head, or the compression nut? You need to undo the chrome nurled ring to inspect under head. Turn it anti-clockwise looking end-on to the head - mole grips or pump pliers are ideal if tight.

Though if it is leaking from under head, best to replace. Not very expensive.

I think its from the nurled ring. You can see the drip here:

Replacing is a bit of a last resort as this is the furthest away rad and would involve a complete drain

 

[D_Hailsham]

I think its from the knurled ring.

Remove the control head by undoing the knurled ring (top towards the wall in your pic.) Water will not come gushing out! You will then see the control pin. Water is probably leaking slowly from the seal round the pin.

Replacing is a bit of a last resort as this is the furthest away rad and would involve a complete drain

Not necessarily.

If you have an open vented boiler with a Feed and Expansion tank in the loft (the small tank if there are two), you can 'bung' the feed and vent pipes which will then set up a vacuum in the pipes, so you can remove and replace the TRV without draining down. You also have to close any auto air vents. You need a Drayton 'Draineasy' kit (B&Q etc).

On a sealed system or combi boiler it's even easier. Close any auto air vents and any valves on the boiler. Then open the bleed valve on the radiator until no more water comes out. This sets up a vacuum in the system. Shut the bleed valve and the lockshield valve on the rad (other end from TRV - count turns so you can reset to same position). Remove and replace TRV. Reset LS valve. Open any closed valves. Reset the boiler presure.

 

[steven.french]

Not necessarily.

If you have an open vented boiler with a Feed and Expansion tank in the loft (the small tank if there are two), you can 'bung' the feed and vent pipes which will then set up a vacuum in the pipes, so you can remove and replace the TRV without draining down. You also have to close any auto air vents. You need a Drayton 'Draineasy' kit (B&Q etc).

On a sealed system or combi boiler it's even easier. Close any auto air vents and any valves on the boiler. Then open the bleed valve on the radiator until no more water comes out. This sets up a vacuum in the system. Shut the bleed valve and the lockshield valve on the rad (other end from TRV - count turns so you can reset to same position). Remove and replace TRV. Reset LS valve. Open any closed valves. Reset the boiler presure.

Wow thats really good to know. Physics is great isn't it . I have a vented boiler with two tanks (one for the boiler, one for the water tank). How would I know which is the vent and feed pipes? I presume the vent is the one that opens above the water tank, and the feed is the one at the base of the tank?

I don't know if i have any auto air vents - all the rads have these valves on and the boiler is an old Ideal Elan WLX if that helps.

I'll try looking at the valve first and see if i can tighten the pin seal first. Thanks for your help.

 

[D_Hailsham]

I have a vented boiler with two tanks (one for the boiler, one for the water tank). How would I know which is the vent and feed pipes? I presume the vent is the one that opens above the water tank, and the feed is the one at the base of the tank?/quote]
That's correct.

I don't know if i have any auto air vents

Look in the airing cupboard. If there is a vertical pipe, usually on the feed from motorized valve to HW cylinder, which goes nowhere, it may have a valve on the top. Here's a pic of mine, so you can see what I mean. The brass thing near the top with a red cap is an auto air valve.

View media item 36821

I'll try looking at the valve first and see if i can tighten the pin seal first.

Unfortunately they are not like normal rad valves where you can tighten the top nut to squash the packing. Most TRVs have 'O' rings as seals, so when they're gone, they are gone.

 

[steven.french]

Look in the airing cupboard. If there is a vertical pipe, usually on the feed from motorized valve to HW cylinder, which goes nowhere, it may have a valve on the top. Here's a pic of mine, so you can see what I mean. The brass thing near the top with a red cap is an auto air valve.

I definitely don't have one of those nowhere pipes. Reading the instructions for the drain easy kit, it states after bunging the pipes you need to bleed the radiators then let the water flow for a minute to create the vacuum. How do I flow the water? Leave the pump on or something?

Unfortunately they are not like normal rad valves where you can tighten the top nut to squash the packing. Most TRVs have 'O' rings as seals, so when they're gone, they are gone.

OK well thats this weekends little project sorted then!

 

[D_Hailsham]

Reading the instructions for the drain easy kit, it states after bunging the pipes you need to bleed the radiators then let the water flow for a minute to create the vacuum. How do I flow the water? Leave the pump on or something?

No; you just wait until no more water comes out of the rad bleed valve. Then close the bleed valve and the LS valve on the radiator (count turns so you can open it to the same place).

Make sure the boiler and pump are off

If the water flow doesn't stop, it means that the bungs are not making a good seal in the pipes. You may have to fiddle about a bit to get a good seal on old pipe. Some even recommend using a carrot as a bung! (Don't know what they would do if it snapped off, leaving part stuck in the pipe. )

 

[steven.french]

No; you just wait until no more water comes out of the rad bleed valve. Then close the bleed valve and the LS valve on the radiator (count turns so you can open it to the same place).

Make sure the boiler and pump are off

If the water flow doesn't stop, it means that the bungs are not making a good seal in the pipes. You may have to fiddle about a bit to get a good seal on old pipe. Some even recommend using a carrot as a bung! (Don't know what they would do if it snapped off, leaving part stuck in the pipe. )

I presume you pop a rabbit into the tank and let it deal with the carrot

Ok thanks for all your help, have a great weekend.