Single zone underfloor heating & open vented system?

[PhilipKS]

Hi,

We've got a Y-plan open vented system and are looking to add a single zone UFH in a new conservatory.

We've had an installer round who wants to convert the system to an S-plan and move the pump from the upstairs airing cupboard (by the 3 port valve) to the boiler cupboard downstairs - fair enough i think i follow the logic of the need to create zones but...

he's also saying that we need to change to a presurised sealed system - he's concerned that hot water will be forced through the system vent. Its an old (25+ year) microbore system (with a new boiler and fast recharge cylinder added last year) - lots of hidden pipes etc so concerned (aside from cost!) that it won't be up to operating under higher pressure -

any thoughts?

cheers
Philip

 

[cider]

I (personally) dont see the need in altering it.
Ive done a similar job before now and kept it dead simple by running a seperate circuit to the airing cupboard, all open vent but had a pump on the UFH manifold controlled by a stat in the conservatory.
When the UFH has been on a while it will take very little from the rest of the system.
Yes it will only run when the house heating is on, but if its a screeded floor it will continue to give off heat for a few hours after the heating is off due to the delay that it has to heat the screed (so you can sit with your g&t in you nice new conservatory after the heating has been off in the rest of the house) .

Cider