Replacing primatic cylinder

[kedsy]

Would it be ok to place a 2 port valve in the boiler return as suggested in the following webpage?

http://www.gasman.fsbusiness.co.uk/gravity_hot_water_pumped_heating.htm


My boiler has 4 pipes from it, 2 for supply and return for pumped heating, and 2 for supply and return of hot water. If I were to get this converted to fully pumped it would mean two of the pipes would not be used? So would need to get 3 port valve fitted after pump then take one pipe off to heating and one off to cylinder?

 

[ChrisR]

WHat you CAN do is stick a pump and 2 port valve on the pipe which goes tothe cylinder, with a pipe thermostat. Wire it so that whenever the pipe is hot AND you want the hot water heated, the pump comes on. WOrks fine done it many times.
You'd want to consider effects of the pump llike sucking air/pumping over carefully - but it should be possible.

 

[croydoncorgi]

Key point is that an unvented cylinder MUST be protected from overheating by a 2-port spring-return (ie. spring-shut) motorised valve. A 3-port won't do.

 

[kedsy]

So the setup above would be sufficient to protect from overheating?

Would be extremely difficult to alter the pipework in other parts of the system but could get access to pipework near cylinder.