Diameter of vent pipe on vented HW cylinder

[Licklieder]

How critical is the diameter of the vent pipe on a HW cylinder ?

the run from the hot water tank in my ground floor 1968 built flat is in 15mm, (or the imperial equivelant). When I replaced the tank for a Megaflow, it never occured to me at the time that i may need to upgrade the vent pipe too....

 

[AlanE]

What vent pipe on the Megaflow?

 

[Dan Robinson]

Why are you worried about the vent pipe from your open vented system on an unvented cylinder?

 

[xr4x4]

Ditto I'm confused..

I'm sure the person who installed it know what they where doing.

 

[spareshunter]

it never occured to me at the time that i may need to upgrade the vent pipe too....

Has it occurred to you to put in a pressure relief valve, if not we wait for the bang fall out glasses.

 

[Agile]

Its just as well that unvented cylinders can only be legally installed by qualified people who know how to that safely!

Tony

 

[spareshunter]

Yes Tony I'm glad as well that legislation is in place to protect everyone from disaster and it is well "policed" to prevent any accidents before they happen. I will sleep easily tonight on that knowledge.

 

[Licklieder]

Apologies for the confusion, it made sense to me when I wrote the question.

I mean the diameter of the vent pipe on my open vented system on my Megalife cylinder (not Megaflo as originally stated)

 

[spareshunter]

Megalife cylinder, What model number more info required bit like saying Ford car.

 

[sooey]

The instructions say 19 mm bore diameter minimum, so that's what you need.
In other words 22mm.
But you knew that didn't you?

 

[Licklieder]

But you knew that didn't you?

Yup, was just hoping that I didn't have to - it's a heck of along run out the flat and up the utility riser to the header in the attic. Ah well one more letter to the landlord to ask for permission to do something then.

Any suggestions on whether to keep the run in copper or use poly pipe aka JG Speedfit or similar ?