Basic Heating System (no hot water) - what controls needed ?

[Andrew]

Assuming a heat-only sysem with boiler, pump and radiators (emitters!!), apart from a thermostat what controls would be needed other than a timer ?.

I assume that a programmable stat would do the timing and temp control, so no need for a wiring centre.

Would the boiler provide the power for the pump or is a relay required ?.

[Steve Walker]

Pump operated from the boiler will allow for timed overrun. Pump in parallel with the boiler power connections from a 'stat switching mains will just not have an overrun facility. System boilers have the pump and an expansion vessel built in.

SteveW

[Cynic]

Different models of boiler have a number of options. There are plenty of wiring diagrams on t'interweb for the possibilities or you can look at the installation instructions for whichever boiler you decide on.

[Tricky Dicky]

It might be better to go to the DIYWiki first and read up about what systems are available and which you think suits you then come back with specific questions, it is to big topic to reply in a return post.

Richard

[Andy Burns]

Also what controls Part L might require (if it's a new or replacement boiler) these vary depending if it's a combi or not (the O/P did say system boiler) and size of dwelling.

[alan_m]

It may depend on the boiler but mine provides the power to the pump which includes the pump overrun to stop the pump switching off instantly off the heating demand has been satisfied. The heat exchanger will still be hot when the burners switch off and if the pump is stopped immediately at this time the latent heat in the heat exchanger will be transferred to the non flowing water - hence the need to keep it being pumped for a while.

[Dave Liquorice]

needed

Thermostatic valves on radiators if you want to heat some rooms more (or less) than others.

A change over pipe stat will sort that though

/ Room Stat / +V ----+----o o----+----------> Boiler | | | | | o cold | \ | \ | o-------> Pump | | +-------------o hot