Plastic or metal isolation valves on jg speed fit shower feed plumbing

[Adam1991]

Hi, I'm working out which isolation valves to use on our hot and cold water feeds to the shower in our NB. 

 

Can I use this plastic isolation valve below on the hot and cold water feeds? (it says max temp 65 degrees)

JG Speedfit 15SV Isolating Valve 15mm 5 Pack | Isolating Valves | Screwfix.com

 

OR should I use metal isolation valves like these? 

JG Speedfit Isolating Valve 15mm | Isolating Valves | Screwfix.com

 

The metal ones are apparently also for central heating - what does this mean? Is central heating the same as your hot water supply to shower, sinks and rads? 

 

Thanks! 

Edited May 13, 2022 by Adam Mc Gowan

[BEngo]

You can use the plastic ones if you ensure that they never see any hot water at more than 65 C.  How you do this depends on how your hot water is heated. I would use the metal ones just in case, and because the plastic ones are unlikely to last well at 65C.

 

Central heating is the supply to the rads and heating coil in the calorifier, where fitted-only.  These pipes are typically too hot for too long to succesfully use plastic valves.

 

Supply to the taps, calorifier outlet etc. is called domestic hot water. 

 

Ensure you support all plastic pipes which will get more than just warm very carefully.  They sag summat 'orrible between support points once they get hot.

 

N

 

 

[Tony Brooks]

I would add that if you are using plastic pipe with compression fittings make sure you use METAL pipe reinforcing inserts. Not only does plastic pipe sag horribly but also seems to soften under compression fittings, so you need stiffer reinforcement.

.

[GUMPY]

Also if using plastic pipe for central heating it needs to be barrier pipe and not the normal single skin stuff

[Slim]

The other thing about isolation valves is ALWAYS get lever operated not knob or  slotted head. Levers may not be so aesthetically pleasing but you can always turn them.

[Tracy D'arth]

Not gate valves, they are not the best for full shut off use.

[Jen-in-Wellies]

If your hot water in the calorifier can get significantly higher than 40C, then it is a good idea to have a thermostatic mixing valve close to the calorifier. This mixes cold in so that the water isn't hot enough to scold some one. If you have a thermostatic mixing valve in the hot water, then your hot isolation valve at the shower won't be getting to 65C.

If the calorifier is heated by the engine, for example, then internal temperature could easily reach 80C, which could scold some one turning on a hot tap.

I've use the plastic Speedfit valves you linked to. They have been in the boat 15 years, and still work fine on the odd occasion I need to isolate a tap, or whatever.

Edited May 13, 2022 by Jen-in-Wellies

[Slim]

3 hours ago, Tracy D'arth said:

Not gate valves, they are not the best for full shut off use.

To clarify, I mean lever operated ball valves.

[Tracy D'arth]

3 minutes ago, Slim said:

To clarify, I mean lever operated ball valves.

I did get that. I have a hatred of cheap gate valves. Modern ball valves are so much better. 

[Slim]

9 hours ago, Adam Mc Gowan said:

Hi, I'm working out which isolation valves to use on our hot and cold water feeds to the shower in our NB. 

 

Can I use this plastic isolation valve below on the hot and cold water feeds? (it says max temp 65 degrees)

JG Speedfit 15SV Isolating Valve 15mm 5 Pack | Isolating Valves | Screwfix.com

 

OR should I use metal isolation valves like these? 

JG Speedfit Isolating Valve 15mm | Isolating Valves | Screwfix.com

 

The metal ones are apparently also for central heating - what does this mean? Is central heating the same as your hot water supply to shower, sinks and rads? 

 

Thanks! 

See my other posts. If you fit the ones you linked to you will regret it in the future