DIY Doctor UK DIY Forums

Hi all,

I have central heating which is arranged as an s plan plus system. It was fitted around 14 years ago when my house was renovated. There is UFH in kitchen, rads elsewhere; it's a 3 storey large house.

The manifold, pump etc for the UFH are situated about 6m away from my boiler, both of which are in the basement of my house. The UFH is for a large kitchen/breakfast room approx 10m x 6m plus a utility room.

As far as I can tell the (wired) thermostat for the UFH only controls the zone valve - that is to say there is no wire from the UFH 'wiring centre' to the boiler.

The UFH as well as DHW and rads circuit are all controlled via a Horstmann 3 channel programmer sited next to the boiler. This sets the on-off times for each circuit operating DHW and rad zone vales and calling for heat from boiler.

SInce the kitchen floor (the one with UFH) is stone tiled, I was advised on installation to keep the UFH channel of the programmer on permanently (due to the thermal latency in the stone floor I guess).

Is this a normal configuration?

ISTM that I am permantly heating the 6m flow & return pipe from boiler to UFH manifold & pump even when the UFH is up to temperature. Yes, I know the zone valve will be closed in these circs but none the less it doesnt seem very efficient to me - am I missing something here???

Thanks for any advice - I am looking to replace all heating controls in my house and will probably call in an expert to do so but I'd like to understand a little more about what I actually have right now.

With gas central heating the idea is in heart of winter the boiler never switches off, but modulates, i.e. turns down, to archive this everything needs to be analogue, however in practice there is often some digital (on/off) used as well, but there are a host of methods to control the boiler.

The main point is the return water to boiler needs to be cool, so the TRV is king doing most of the control in most systems.

EPH do a thermostat which can be set as master/slave and work the motorised valves on/off while the boiler is controlled up/down, but it seems there is no perfect system, it is all a compromise.