Lever valve on hot exit from unvented cylinder

[stratplus]

Afternoon all, when installing an unvented cylinder does anyone fit an isolation valve on the hot run as it leaves the cylinder?
Been told its against regs but can't think of a reason why it would be. First pic in the Bpec manual shows a cylinder with lever valve on the hot.
Surely it's no different to having a tap on the end of a run if it was turned off.

Just curious to your thoughts on this.

 

[happyflyer]

Manufactures data

 

[stratplus]

Cheers for reply, does that say isolation valves are required. Isn't that just at the draw off points?

 

[AWheating]

not sure if its against the regs but its probably not best practice. The main issues with isolations on un vented is to ensure that its not possible to isolate the safey devices from the cylinder.

Why do you need to have a valve there? why not isolate the cold before the combi valve/set up?

 

[snowhead]

I believe the valve shown is meant to be local isolation, not fitted at the cylinder.

This pic shows it better, page 14 fig 7;

http://www.heatraesadia.com/docs/Megaflo_eco_-_36006062_issue_09.pdf

 

[stratplus]

I personally don't fit the valve there but got sent a pic of one saying they thought it was against regs.

 

[stratplus]

 

[stratplus]

This is the pic from the new Bpec manual.
Seen it done on quite a few installs now.

 

[happyflyer]

I wasn't with the question the first place, maybe I should ask you this question, whats the difference between a 22 mm gate valve near the outlet of a Mega-flow and the taps on the end of the lines in the bath and kitchen, none, the only advantage of fitting a GV just after the Mega-flow is you don't need to drop the pressure in the MF to change a tap etc. Dropping the pressure in the MF can use a fair bit of water.

 

[SafeGasInstall]

I dont fit any valves on the outlet of the hot water near the uhwc and personally dont see the point of having one there

 

[Mike Jackson]

I always fit one. Means I can leave the balanced cold supply on with the hot isolated. I always fit one before the valve assembly and one each on the hot and cold outlets.

 

[plumber0808]

I don't fit them on domestic properties as most are too small to make any difference. Big installs then yes.

 

[Howsie]

Fitted by someone who doesn't understand an UV set up. Why could you possibly need one?

 

[kozak1968]

A few years ago we fitted isolation valves on the outlet of unvented cylinders as per drawing. The building control wanted the leavers removed as he said they were a danger. What a load of rubbish! the expansion in a Megaflow is before the isolation valve. All Unvented cylinders must be isolated safely so the expansion protects the cylinder.

 

[tackleburger]

I dont fit any valves on the outlet of the hot water near the uhwc and personally dont see the point of having one there

I agree. The point of putting it on the cold before all controls is to give one point of isolation that can be used to service the whole hot water system. Although there is no reason a valve can't go on the hot side it is sort of pointless and people need to stop fitting gate valves to invented systems I,m sick of working on systems with gate valves for isolation that pass. As for using water when taking the pressure off that is a rare occurrence really and would be negligible in the scale of things. Putting an extra valve on is a waste of money unless some joker has put a gate valve on the feed.

 

[Mike Jackson]

Fitted by someone who doesn't understand an UV set up. Why could you possibly need one?

Because the customers like seperate isolating valves for the hot and cold.

 

[SafeGasInstall]

Never Ben asked by a customer to fit a lever valves or gate valves

 

[happyflyer]

Would you put your name to this job, if not why???


I also do see a 1/4 turn valve on the HWS takeoff, nowt wrong with that IMO, how many mistakes can you spot, BTW exclude the skirting board and the immersion heater cable clipped to the blow off pipe

 

[chris watkins]

Would you put your name to this job, if not why???


I also do see a 1/4 turn valve on the HWS takeoff, nowt wrong with that IMO

View attachment 13468

What apart from the filling loop still connected (Water Regs) & on insulation on the pipework for a metre away on all cylinder con's (Part L), Where's the composite valve & isolation on the cold in then ? otherwise valve on the outlet no problem.

 

[stratplus]

I don't think it's a bad idea tbh as Mike says if its a balanced system you can isolate the hot without the cold.

 

[Howsie]

Because the customers like seperate isolating valves for the hot and cold.

Ignore me. I was very very pished and should not be allowed near technology in that state.