High gas usage for boiler.

[stevedurban]

We were away 2 weeks ago - and I turned heating and water off. The usage was 0 for every day we were away.

 

[ShaunCorbs]

Right ok turn just heating on for two hours and retest

 

[John.g]

So you have used 148kwh in, 3X2, 6 hours in total which is almost 25kwh (per hour), is that correct? Is it a 24kw boiler, can't remember?.
Can you set up a camera to monitor the Gas Meter to monitor those 2 hours each day or have you noted the readings at the end of each day period and start of next days period to ensure no usage in the intervening time?.

If the ABV pipework has been installed then the supply to it should be teed off before any motorized valve, can't see it properly but if its taken off before the (or any) HW M.valve then correctly installed, so as long as the boiler is firing the ABV is "live" and can leak, but boiler will hardly be firing (we hope) with both M.valves shut?.

I thought you meant the central heating was on for 3hrs/day.
148kwh/day, if so, seems a bit on the high side, 148/17.5= 8.46kwh/hr, bit on the high side but not outrageous either.

 

[stevedurban]

Right ok turn just heating on for two hours and retest

Ok - will do now

 

[stevedurban]

So you have used 148kwh in, 3X2, 6 hours in total which is almost 25kwh (per hour), is that correct? Is it a 24kw boiler, can't remember?.
Can you set up a camera to monitor the Gas Meter to monitor those 2 hours each day or have you noted the readings at the end of each day period and start of next days period to ensure no usage in the intervening time?.

If the ABV pipework has been installed then the supply to it should be teed off before any motorized valve, can't see it properly but if its taken off before the (or any) HW M.valve then correctly installed, so as long as the boiler is firing the ABV is "live" and can leak, but boiler will hardly be firing (we hope) with both M.valves shut?.

Just thinking, the boiler is/should only be started when either of the M.valves open by means of (end) switches in their actuators.

Just on the last point - I spent a fair amount of time previously running back and forth watching the valves and boiler to check it didn’t have the flame symbol lit on the front whilst the valves were closed and it didn’t seem to! The boiler is still pumping (which i believe is correct) but no flame.

 

[John.g]

What do you mean by the boiler pumping?.
I think Tado works something like Evohome where the rads "TRVs" are actuated/controlled by it, and depending on actuator positions fires the boiler on/off so wonder what does the the CH mot.valve do?.

 

[stevedurban]

What do you mean by the boiler pumping?.
I think Tado works something like Evohome where the rads "TRVs" are actuated/controlled by it, and depending on actuator positions fires the boiler on/off so wonder what does the the CH mot.valve do?.

I meant I could hear the pump running on the boiler - but the “flame@ was off!

Here was the reading 2 hours ago


Here was the reading after 2 hours

 

[stevedurban]

Revta

I meant I could hear the pump running on the boiler - but the “flame@ was off!

Here was the reading 2 hours ago
View attachment 72866

Here was the reading after 2 hours

View attachment 72867

Re tado - yes - there are TRV’s on all radiators - and they speak with the thermostats In the rooms. The thermostats tell the TRV’s to open and the boiler to kick in. We have it that only the downstairs thermostat has the ability to call for heat - the upstairs only gets to temperature when they downstairs is calling.

 

[John.g]

Your meter readings = 21.9kwh for 2 hours (boiler on, I hope)
Interesting re Tado, I can understand the upstairs M.valve just calling for heat when its roomstat calls, but if its the same so for the DHW M.valve, then in the summer with no CH demand how is this catered for, unless there a separate relay fed from the HW M.valve or somewhere else that calls in the boiler?.

Re boiler running pump, in a normal S plan this will run continuously with a call for the boiler to run, the boiler burner will cut in/out if its output is > the heating demand but pump will continue to run and will only stop after no call from CH or DHW (or boiler programmed off). So why is your pump running all the time, is the boiler on all the time and if no demand will fire up/down on its own boiler stat?.

 

[stevedurban]

Your meter readings = 21.9kwh for 2 hours (boiler on, I hope)
Interesting re Tado, I can understand the upstairs M.valve just calling for heat when its roomstat calls, but if its the same so for the DHW M.valve, then in the summer with no CH demand how is this catered for, unless there a separate relay fed from the HW M.valve or somewhere else that calls in the boiler?.

Re boiler running pump, in a normal S plan this will run continuously with a call for the boiler to run, the boiler burner will cut in/out if its output is > the heating demand but pump will continue to run and will only stop after no call from CH or DHW (or boiler programmed off). So why is your pump running all the time, is the boiler on all the time and if no demand will fire up/down on its own boiler stat?.

So we have a standard 2 splan - one M.valve for heating (which feeds all the radiators in the house) and one one for water.

Tado controls both independently. When the downstairs thermostat calls for heat - it tells the tado controller to open the DHW valve - and boiler starts etc etc. the other thermostats around the house just tell the radiators in their “zone” to open and close as needed. If the downstairs is calling for heat at that moment - the radiators will get hotter. If downstairs isn’t calling for heat - they won’t get hotter. (That’s our choice - and was recommended by tado to do this)

When I was mentioning about hearing the pump - I was referring to the overrun. It sounds like the pump keeps pumping for about 5 mins from the time the last valve closes - and then the boiler is quiet. I presume this is by design.

When either valve is open - you hear the boiler in full force.

You mentioned about the boiler pump running constantly with a call to the boiler to run - and not burning if the output is > the heating demand? But surely if the heating demand isn’t met - the boiler should be burning? And if the heating demand is met (room stat hits temperature) the value would close - and the boiler would stop anyway? So what scenario would the valve be open - but not calling for heat?