Electric Boiler with an unvented system... Expansion Vessel!

[wmshome]

I have an Aztec electric boiler, and a Ariston sti125 indirect unvented cylinder...

The problem I have is with installing the expansion vessel/s...

From the Ariston Cylinder installation guide, the expansion vessel goes after the combi valve on the cold coming in. This is fine I think. But then the Aztec Boiler guide shows an expansion vessel on the return to the boiler.

DO I need to install two expansion vessels?

 

[mickyg]

The unvented cylinder should be installed by a competent and qualified unvented engineer who will know exactly how to do it.

 

[wmshome]

Being fully qualified in the unvented systems myslef, I do not have a problem with the installation of the cylinder side of things. The question I am asking is about the Electric boiler. It is my first time of installing one, and feel it may need one as a saftey device, as it is a sealed system which has no blow off like with other boiler systems...

 

[ajstoneservices]

The unvented and Aztec boiler each need an expansion vessel.

 

[mickyg]

The problem I have is with installing the expansion vessel/s...

You refer to both expansion vessels

From the Ariston Cylinder installation guide

Why are you taking about the cylinder installation guide when you haven't got a problem with it?

You can understand my confusion right now

 

[Gasguru]

Yes the boiler must have an expansion vessel, pressure gauge, safety valve etc etc and comply with the relevant regulations

It's partially explained in the manual but you should be competent in sealed systems.

There is however one safety issue in the manual....it shows isolating valves on the boiler but the safety valve fitted fitted to the system side....a major safety flaw....safety should come straight off the flow before the valve.

 

[twgas]

sealed and unvented systems should be left to pros - there are serious safety implications.

 

[wmshome]

Yea yea ok... I can plumb all day long, but have great problems with communication, lol...

My sincere apologies. But hope you get what I mean now...

 

[wmshome]

Thankyou 'gasguru'. Answers my question fully, and thanks for the tip with the valve. Can see what u mean...