Wiring up a Wireless Thermostat

Discussion in 'Electrics UK' started by Extooth, 18 Apr 2017.

  1. Extooth

    Extooth

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    Here is the diagram of the boiler: eeeerty.JPG

    Unit Diagram: Untitled.png

    I had a look at the PCB console: DSC_0001.JPG


    From what I understand I Am to take out the jumper pin in the Room stat terminal, place cables A + B into them, (does it matter which way?), and then place a L + N into the mains terminals of the boiler. Does that seem correct?
     
    Last edited: 19 Apr 2017
  2. ericmark

    ericmark

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    BDR91 centre to boiler

    N = Neutral to 6 on boiler

    L = Line to 2 on boiler (right hand terminal marked Room Stat)

    A = Common to 2 on boiler I will guess the extra L on the BDR91 is to allow you to fit a link wire L to A on the BDR91.

    B = Normally open to 3 on boiler the link on boiler will need to be removed. (Left hand terminal marked Room Stat)



    This assumes it is a combi boiler, we don’t know if it is plumbed that way or not, it will matter A and B if linked at thermostat. 2 needs to be A if it links to L or when it turns off the thermostat will lose power.
     
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  4. Extooth

    Extooth

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    I think it is just a conventional oil boiler. The instructions show heatslave 15/19 as a combi, however my boiler guy said this is a conventional. Hot water for example can only be used for 30 seconds if the hot water is set to off, however when on, one can then have showers etc. So would I use the burner (direct control) diagram instead?
     
  5. ericmark

    ericmark

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    Please don't get combi and condensing mixed up.

    The Combi boiler does away with the hot water tank and gives you instant hot water. The hot water bit is internal to boiler so you don't have to worry about external wiring to give hot water, although the boiler may have the option to run as a combi it is not always used, as when used you can't add hot water from other sources like solar or back boiler, so it does need plumbing as a combi not just be combi type.

    The Condensing boiler extracts more energy from the fuel, you can get both combi and condensing in the one boiler and you can get condensing with solid, liquid and gas fired boilers although rare with solid fuel, the main difference to use is it monitors return water temperature and adjusts flame height (not solid fuel) so you need to have TRV's fitted for it to work correct. It does not in theory need a room thermostat.

    Out of interest although will not effect you, the solid fuel condensing has a water (or other) heat store because you can't turn down flame, the boiler runs at a set output throughout the burn. Then separate pump circulates water as heat is required.

    From what you have said it would seem you have a Combi boiler, however as to condensing not so sure, the idea with condensing is the TRV controls the boiler, however the anti-cycle software simply does not work in the Summer, so you still need a wall thermostat simply to turn the system off. This is at the moment causing me problems. Once the temperature starts to raise you don't want the boiler to get house too hot, both for comfort and cost of running, if you have a room set at 17°C on the TRV and 18°C on the room thermostat then it would work, but 17°C is too low, heat from other rooms would cause the room to get too hot, and so switch off central heating too early. Go up a degree and then too hot in summer. Balancing the system seems impossible unless you have a thermostat outside to turn off the heating or use "If this than that" (ITTT) to monitor weather reports. Theory may be good, in practice it needs the house holder to turn off central heating in the summer.
     
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  7. Extooth

    Extooth

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    Getting back to you late, but this worked a treat. Wired up according to the Burner (direct Control) Diagram which is what you have linked above. (the Combi Diagram is what confused me during this whole process, it wasn't needed in the end). The new thermostat is up and running, I have also removed the Frost stat that he wired incorrectly and was using a wrong fascia for :O

    Anyways, thanks again, greatly appreciate your detailed replies!
     
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