Un-vented installs

[chris watkins]

Hi All
Have you any idea's why it is that 75% + of all the un-vented hot water installs I go to, are incorrect & do not meet Part G Building reg's (& I have seen a lot in my time) don't get me wrong some are silly things like discharge pipes too long or running up hill but others are down right dangerous. Why is it so difficult to get these right ?????

and how the B***hell do Building Control or NHBS sign them off ??????

 

[Gray0689]

How are the discharge pipes to long??

 

[Mike Jackson]

Building Control haven't got the faintest idea about how they should be installed. They just assume the installer knows what they are doing. They don't even check the installer has a ticket most of the time. Until the unvented equivalent of Ronan Point happens it will stay the same.

 

[mark_mc]

i have a question about a unvented install can you install the 3 bar prv on the incoming mains and at the cylinder just a stopcock and check valve with a safety valve and fo away with the prv at the cylinder.

 

[Mike Jackson]

As long as there are no valves between the cylinder and the expansion relief valve it can be done. As long as you can separate the combination valve into the correct components. It's just as easy to fit a separate PRV on the incoming main though. They're not a lot of money and saves any confusion in future.

 

[tamz]

Like everything else, combination of laziness, ignorance and stupidity. No excuse for any of it.
Building control or NHBC only see the new build stuff and they seem to know or care very little about them.

How are the discharge pipes to long??

Incorrectly sized for the run length.

 

[Gray0689]

i have a question about a unvented install can you install the 3 bar prv on the incoming mains and at the cylinder just a stopcock and check valve with a safety valve and fo away with the prv at the cylinder.

Where are you going to balance the cold

 

[mark_mc]

thats great. cant break the combination valve down but will install a prv on the incoming main and then at the cylinder a valve arrangement in order valve, check valve, pressure relief valve, expansion vessel then to cylinder

 

[mark_mc]

if i install a prv on the incoming main into the house all supplies will be 3 bar no matter what.

 

[Gray0689]

Are you tacking a 22mm mains to cylinder