lt;li>Override: 1 hour boost (Hot Water only), 1 hour extension to On period (Hot Water only), instant advance (Central Heating only)</li> With most leccy flow through boiler systems Rob; the HW is just heated by the immersion heaters, to confirm this do you have two immersion heaters? 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. Hi.. Thanks for the reply. The C27 thats in place at the minute is working to the extent where I can turn the heating and HW on and off, Just not set timers, (screen is dead) oil combis work in different ways from gas combis, the easiest way for you is to take a cable from your existing 2 channel programmer

HEATING PROGRAMMER REPLACEMENT AND WIRING GUIDE - TLC Direct HEATING PROGRAMMER REPLACEMENT AND WIRING GUIDE - TLC Direct

lt;li>Operating periods per day: 3 per day for Central Heating and 3 per day for Hot Water</li> The wiring is just to complicated for me to work out. Could anyone help with what wires go where on the heat link? 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. Many modern thermostats have a dead zone. If the temperature deviates less than 4°C from the set temperature, the system will not heat or cool. This so called dead zone of the thermostat prevents the system from turning on and off too often, saving energy.So I have finally got round to doing this today and now having finally removed the C27, I only have wires on 3 & 4, Looks like I just connect these to B? But I believe I need a loop from the Second L to A The Nest Heatlink will need the usual Live and Neutral, from the same supply as the programmer etc, for it's power.

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

You can now disconnect all of the wires going to the old thermostat and remove the cable and thermostat.Home > Home & Decoration > Thermostats > Horstmann Thermostats > Horstmann CentaurPlus C27 Thermostat Manual Horstmann CentaurPlus C27 Thermostat Once you have transferred the wires from the C27 to the Heat link, then the Heat link (L) terminal also needs linking to the two 'common' terminals (2) and (5) With 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. There is a separate immersion switch I can use to heat the water, but this can become expensive I I forget to turn it off.

CentaurPlus C27 Series 2 User Operating Instructions CentaurPlus C27 Series 2 User Operating Instructions

The C27 is a two channel programmer, but if your HW is heated independly of the boiler, then it should just be a single channel, controling the CH only. 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. Override: 1 hour boost (Hot Water only), 1 hour extension to On period (Hot Water only), instant advance (Central Heating only) If that's all correct then what do I need to connect the hot water and central heating commons on the nest heat link. I'm reading about jumpers from the live?Just done that and its all up and running - Thank you so much - Saved me alot of money there getting it installed. note it says Centaur Plus is volt free, so it seems the centaur plus is same as Hive single channel and standard one is same as Hive duel channel, so I would be hunting on the actual device to see if there is a diagram. Your picture clearly shows a brown sleeve on the blue wire going to 3 so clearly a line not neutral. The best place for a thermostat is approximately 1,5 meter above the ground. Never place the thermostat nead a radiator or other heat emitting equipment or in direct sunlight. Choose a room that is used often. In most cases this is the living room. The diagram above will allow you to identify what the wires in each terminal of the C27 does. Once identified, the wires are moved to the Nest Heat link terminals that have the same function. Look at the wiring diagram for your make/mode of thermostat that you are removing. If you don't have the instructions for it, a diagram is usually printed inside the lid. This will show which are the two live switching wires, and which is the neutral wire. (If there is a neutral present. Not all thermostats need or have one fitted)