Horstmann - CentaurPlus C27 - Series 2 - Two Channel 7 Day Programmer

Product Information

This seems to be the other end where the programmer is (the white cable with the blue wire with yellow tape around it) Im removing a Centaurplus C27 with stored hot water and fitting the Evohome setup that I had from my previous house. Old house was gas with on-demand hot water, so I have bought the hot water add on for this, Which leaves me wiring up 2 BDR91s in replacement of the old C27.

Trianco Aztec/ Centaurplus C27 problems? | DIYnot Forums Trianco Aztec/ Centaurplus C27 problems? | DIYnot Forums

Have just moved into a flat with a trianco Aztec electric boiler paired with a Horstmann Centaurplus C27 programmer. Apart from a big white tank and (supposedly) knowing how to set the timer, that's as far as my knowledge goes with this system. My problem as far as I know is the timer. When I switch on the hw the water doesn't heat but the central heating gets hot!?. The ch light on the timer doesn't come on but the central heating defiantly gets hot. Same if I press the boost button, I hear the system start an the central heating comes on again, without the water getting hot. If I press the ch button the heating comes on fine. In short both the hw and ch buttons only turn on the ch?! The Boiler is a Grant Vortex Pro External Combi21e, as the name suggests the boiler is outside in a casing so it's a bit more difficult to trace the wiring.Having a few issues wireing in the Nest Heatlink - mainly trying to work otu what the current Common and Call-For-Heat connections are - have been looking at http://www.horstmann.co.uk/files/86..._guide_CentaurPlus_C21-C27_installer_web1.pdf but havent managed to work it out my self , we also have one thermostat on the system which will be replaced if that helps.

Horstmann CentaurPlus C27 User Operating Instructions Manual

As you have figured, the old room thermostat can't simply be disconnected as this would leave the heating wiring 'open circuit' and it would not operate, the integrity of the circuit needs to be maintained. As not all thermostats are the same, some working out will be required. oil combis work in different ways from gas combis, the easiest way for you is to take a cable from your existing 2 channel programmerWith what you propose, you are connecting CH and HW control wires to the same BDR91. For example terminal 3 is a HW control wire and terminal 4 is CH control wire, yet you propose to connect them both to the BDR91 for hot water. The same is true of terminals 1 and 2 if they are actually fitted.