Why is gas being used during the night?

  • MattB's Avatar
    Level 7
    I didn’t have a close handle on time periods (months) for previous bills and there were lots of estimated readings which were subsequently adjusted approximately quarterly so it will be difficult to tease that out with such a short current time period.

    if there was a faulty zone valve then the boiler and pump would run? The sole radiator not on a smart valve doesn’t seem to warm up.

    I am wondering what controls the four water heated towel rails.
  • Plantagenet's Avatar
    Level 18
    I didn’t have a close handle on time periods (months) for previous bills and there were lots of estimated readings which were subsequently adjusted approximately quarterly so it will be difficult to tease that out with such a short current time period.

    if there was a faulty zone valve then the boiler and pump would run? The sole radiator not on a smart valve doesn’t seem to warm up.

    I am wondering what controls the four water heated towel rails.
    You are correct if a faulty valve micro switch was allowing power through with the timer off, and not energising the valve motor then the boiler and pump would operate . Is your property zoned just using the TRV’s or do you have separate room stats/ programmers for each floor?
  • MattB's Avatar
    Level 7
    @Plantagenet
    ground floor wet UFH in separate zone. First and second floors all in one zone with one wired stat.

    There are 3 zone valves in the system next to the hot water cylinder.
  • Plantagenet's Avatar
    Level 18
    @Plantagenet
    ground floor wet UFH in separate zone. First and second floors all in one zone with one wired stat.

    There are 3 zone valves in the system next to the hot water cylinder.
    One motorised valve will be for the cylinder coil controlled by cyl stat, one valve for first and second floors and the other for underfloor htg. It’s possible any one of these could be faulty if it’s the one for the underfloor heating you wouldn’t really feel any real heat unlike radiators. If you do as others have suggested and turn the boiler off at the fused spur it could indicate if it is an electrical problem causing your boiler to fire when there is no demand from any of the controls on the system.
  • Plantagenet's Avatar
    Level 18
    [QUOTE=MattB;25346]@Plantagenet
    ground floor wet UFH in separate zone. First and second floors all in one zone with one wired stat.

    There are 3 zone valves in the system next to the hot water cylinder.[/QUOTE

    Also if your boiler is installed in an unheated space such as a garage there is a possibility it could have a frost stat situated at the side of it wired to override any of the system controls.it will have a blank covered front , behind Being the
    temp setting, if this was set too high say 5 / 7 degrees centigrade it could cause it to operate, especially now the temps have dropped.
  • MattB's Avatar
    Level 7
    Update:
    I turned the boiler off for two hours. The meter reading was identical before and after. So (as anticipated) not a meter fault.

    All three monitoring modes showed no gas usage during this time. So either a faulty zone valve as suggested by Plantagenet or could it be the towel rails or something else?


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  • retrotecchie's Avatar
    Level 92
    @MattB

    If they are hydronic towel rails, i.e. Piped, then they will be using boiler heat. If the boiler is off, nothing can be using gas. If something somewhere is calling for heat then the boiler will fire. Surely your boiler is also controlled by a timer, so even if something is calling for heat, the timer should cause the request to simply he ignored...unless it's an electrical fault and something is feeding past the timer.
    Don't shoot me, I'm only the piano player. I DON'T work for or on behalf of EON.Next, but am willing to try and help if I can. Not on mains gas, mobile network or mains drainage. House heated almost entirely by baby dragons.
  • MattB's Avatar
    Level 7
    Because of the Tado system the heating side of the controller is set to always on. I really dont want to abandon Tado - I have invested a semi-fortune and it gives us complete control and lots of data on temperatures and calls for heat. I believe we have improved efficiency. Because of the complexity I have not used Tado for the HW. How is it that the towel rails are warm in the summer when none of the radiators are? Would it be linked to the HW?

    I can tell that the thermostats are not calling for heat because the Tado app tells me when they are and this exactly correlates with hearing the TRV open and feeling the radiator warm up.
    Last edited by MattB; 09-12-22 at 19:11.
  • retrotecchie's Avatar
    Level 92
    @MattB

    Any boiler based heating system needs a bypass loop. Possibly the towel radiators are acting as that loop.

    There is something very wrong with a system that 'manages a heating system' in order to be 'more efficient', costs a fortune and runs your boiler at a minimum demand of 2-3kWh ever hour, 24/7.Try putting the heating side on 'timed' and switch off a 'window' between midnight and 7am. See what happens then

    Sorry...it's clearly something your Tado system is not doing properly, or you do have some electrical issues somewhere. If you manually turn the boiler off....no gas consumption.
  • Plantagenet's Avatar
    Level 18
    @MattB
    I still suspect a control fault , irrespective of the timer calling for heat. A fault with a zone valve micro switch if stuck in the on position will pass a live current across the grey wire ( permanent live which is not timer controlled) to the orange wire feeding the boiler. Even if the zone valve is shut with no power to it's syncron motor. Any heat from the boiler could circulate through the bypass normal fitted after the pump but before the motorised valves back through the return pipe. This is fitted in addition to a radiator used as a bypass on the system.Your radiators etc would not heat up in this case. As the motorised valves would be closed allowing no flow through them .ie no power from timer/ stats.
    Last edited by Plantagenet; 09-12-22 at 19:27. Reason: Grammar