Unvented cylinder feed pipe

[tridimnaw]

Hi, Im going to be installing an unvented cylinder to a property next week. I've got the cert and hand books but I can't see any info on pipe sizing for the feed! The ones I've done in the past hve all had a 22 mm rising main, this one has a 15 mm. The pressure and flow rates are good. Will it have an effect on how the system will work? Or should I replace the cold pipe from the stop tap to the cylinder with 22mm pipe?

 

[IDCHAPPY]

So you are G3 registered? I'd be safe and take it there in 22mm mate, everyone I've fitted had a 22mm feed. Last thing you want is the customer coming back and busting your bum if there problems with flow(there probably wouldn't be but why take the chance? ).

 

[sheff paul]

Hi, Im going to be installing an unvented cylinder to a property next week. I've got the cert and hand books but I can't see any info on pipe sizing for the feed! The ones I've done in the past hve all had a 22 mm rising main, this one has a 15 mm. The pressure and flow rates are good. Will it have an effect on how the system will work? Or should I replace the cold pipe from the stop tap to the cylinder with 22mm pipe?

In an ideal world 22mm all the way,best to pipe 22mm down to the stoptap,then in the future they can upgrade the cold incoming.A couple of weeks ago fitted one with 15mm feeding the control valve,with a view to upgrading when there finances permit,worked better than a combi,but same problems when a few taps were open at the same time.If the existing 15mm had poor flow/pressure then it wouldn't be an option

 

[chris watkins]

If you only have 15mm coming in then replacing it in 22mm will only help with the friction losses. On high pressure systems these are relatively small so unless you have lots more than 3bar or a very, very long run of 15mm with lots of elbow in it or they are defiantly going to replace the incoming mains from the street stick with the 15mm into the valve set. You should pipe the outlet through to the cylinder as well as the hot all in 22mm.
What pressure & flow do you have on the existing 15mm???

 

[Destroyer2813]

I've gotta a old black water main coming in my house but ran 22mm back to it and will upgrade watermain when I do my front extension, it works fine at the minute

 

[stratplus]

15mm incoming to a/c in mine too with no issues, just not balanced.

 

[AWheating]

doh matta what size pipe you fit unless the main has a good flow rate. Pointless specin an unvented cylinder for a job unless you have atleast done some checks/tests on the incoming mains supply. Basic g3 stuff.

 

[sheff paul]

I've gotta a old black water main coming in my house but ran 22mm back to it and will upgrade watermain when I do my front extension, it works fine at the minute

got exactly the same incoming into my gaff,took 22mm from it runs fine

 

[sheff paul]

If you only have 15mm coming in then replacing it in 22mm will only help with the friction losses. On high pressure systems these are relatively small so unless you have lots more than 3bar or a very, very long run of 15mm with lots of elbow in it or they are defiantly going to replace the incoming mains from the street stick with the 15mm into the valve set. You should pipe the outlet through to the cylinder as well as the hot all in 22mm.
What pressure & flow do you have on the existing 15mm???

Chris mate I think you need more time on the tools than on the books

 

[tamz]

Unventeds will "work" with any pressure or flow no matter how low ie you will get water out the hot tap but working and working the way it should are 2 different things.

 

[Irish]

Unventeds will "work" with any pressure or flow no matter how low ie you will get water out the hot tap but working and working the way it should are 2 different things.

Too true tamz seen a mega flow in a loft last summer 22mn copper from cylinder back to incoming main 25mm mdpe back to stop tap in the street 12L/m

 

[tamz]

I was at a job last year where some numpty had tied one into the storage in a bungalow straight off the old feed.
I was in changing a valve motor and noticed it. Swaped the pipework around and tidied up a couple of other things for a small fee of course and she couldn't believe the difference :lol:

 

[chris watkins]

Chris mate I think you need more time on the tools than on the books

???????????
Paul mate, don't know what you are suggesting but can assure you had more that enough years on the tools, as you put it, started on these systems in 85/86.
I just think it is nice to be able to do both don't you??

 

[tridimnaw]

doh matta what size pipe you fit unless the main has a good flow rate. Pointless specin an unvented cylinder for a job unless you have atleast done some checks/tests on the incoming mains supply. Basic g3 stuff.

As I said in the op flow and pressure are good! Very good in fact!

 

[chris watkins]

As I said in the op flow and pressure are good! Very good in fact!

Want to give us a clue as to how good they are or have you not measured ???