Changing BSP Valve to 15mm TRV

[RaoulDuke00]

Hello all,

I'm looking to replace a couple of radiator valves in my recently-purchased house, however I'm not sure about about all of the possible connections and adaptors.

I've done some research online and have worked out that the inlet and outlet seem to be 1/2" BSP.

The idea is to replace the valves with a smart TRV, have already bought 2 Eve Thermos which have an M30 1.5 on them. From my learning, it seems I'd need either some kind of adaptor to connect the radiator valve tail and inlet tot he valve, or possible a new 15mm valve tail to connect the radiator to the valve, but still not sure about the inlet.

Has anyone here attempted this before and if so, how can I be sure of measurements etc before buying any new adaptors/tails/etc?

Thanks,

R

 

[oldbuffer]

What you have bought are just actuators designed to fit existing TRVs. ,Unless they fit the existing TRV body (which I don't think they will, you are going to have to buy and fit new TRVs. The ones you have bought come with adaptors for some Danfoss valves, so these, or others with an M30 x 1.5 thread are what you need.

To fit new TRTVs:
1. The radiator to valve connection looks like a 3/4" union connection to me.
2. To suit a more modern valve you would need to change the radiator tail to a compression type. E.g. https://www.stevensonplumbing.co.uk/radiator-valve-tail.html. You can get union connection TRVs but they are more expensive.
3. To make the change I would advise draining the system. Depending on what sort of system you have there are ways of doing it without draining, but only, I'd suggest, for the experienced.
4. Your pipework to valve connection is a compression connection, but not the usual sort. With the system drained, unscrew the lowest nut on the valve body. Remove that nut and the olive between it and the valve (which will be on the pipe). There are various videos on how to remove an olive. If you are lucky, the pipe will be long enough to reach into the inlet of your new valve. If not you will have to extend the pipe.

 

[RaoulDuke00]

Thank you for your quick and detailed reply, oldbuffer

I did forget to mention that I'd bought a 15mm Drayon TRV which came with the valve body and the head, my intention being to use the body to mount the Even Thermo. The Eve fits on top nicely without any of the adaptors to that feels like one part of the equation sorted, just need to measure the pipes and the radiator itself.

Re: the 3/4"; I noticed on the inlet there is a 1/2" marked on it but upside down; is the likely the size of the connection? I've been reading that sometimes 1/2" aren't exact, so I've not taken that as gospel

 

[nicam49]

Hi, just to explain about BSP sizes: ½ inch BSP actually measures ¾ inches OUTSIDE DIAMETER, and ¾ inches BSP actually measures 1 inch OUTSIDE DIAMETER....! Yeah, I know! The BSP refers to the INSIDE DIAMETER of the pipe.
That rad valve of yours looks like a ½ inch BSP connection to the rad tail, BUT the pipework entering from the floor could either be 15mm (modern) or old imperial size ½ inch NOT BSP. - These latter 2 are not compatible, but you can get adaptors.... you'll have to do a bit more googling as I'm not familiar with old imperial ½ inch pipe. (Not BSP) I've just checked, and Screwfix stock solder 15mm to1/2 inch adaptors. So that's good.