High gas usage for boiler.

[stevedurban]

Hi

Not sure if anyone can give any ideas - but
I’ve got a Worcester Bosch junior 24i system boiler.

For the past 10 years I’ve lived In the house - the average usage of gas has been about 10,000kwh. For the past 2 years my average has been 58000kwh. (Boiler is the only gas appliance in the house!)

It’s Regularly serviced. And from the 3 plumbers I’ve had look at it - they’ve all said - it’s just colder than normal so usage has gone up!

Anyone got any ideas? Is that an increase others are seeing?

SG

 

[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?

 

[stevedurban]

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?

P.s - thank you so much for your patience, advice and understanding! I really appreciate it!

 

[ShaunCorbs]

Tbh all looks normal so just higher use

 

[stevedurban]

Tbh all looks normal so just higher use

Can it really be just that??? 185kwh today.

 

[ShaunCorbs]

The meter reads nothing when not on / out

The meter is reporting the correct kWh over time heating / hot water been on around 8 hours total at 24kw

How long has the tado kit been installed?

 

[John.g]

That's correct, all boilers have a minimum output, depending on boiler manufacturer, boiler output etc, it will be ~ say 3 to 6 kw so if the heating demand is below this then the boiler temperature will rise and the burner will cut out when this temperature reaches its setpoint+3C (normally) and the burner will cut back in when the boiler temp is its setpoint-3C plus the boilers anticycling time which may be ~ 3 mins, the pump will continue to run because the demand for heat has not gone away.

"When the downstairs thermostat calls for heat - it tells the tado controller to open the DHW valve" do you mean the CH m.valve? The DHW valve is also controlled by the cyl stat.

 

[stevedurban]

The meter reads nothing when not on / out

The meter is reporting the correct kWh over time

How long has the tado kit been installed?

Correct - the question is is the boiler using more gas than it should?

Tado been installed for 10 years. I added digital tado room stats about a year ago in the hope that it would help… alas it didn’t!

 

[ShaunCorbs]

Doesn’t look like so you’ve had this problem for a while ?

“I added digital tado room stats about a year ago in the hope that it would help… alas it didn’t!”

 

[stevedurban]

That's correct, all boilers have a minimum output, depending on boiler manufacturer, boiler output etc, it will be ~ say 3 to 6 kw so if the heating demand is below this then the boiler temperature will rise and the burner will cut out when this temperature reaches its setpoint+3C (normally) and the burner will cut back in when the boiler temp is its setpoint-3C plus the boilers anticycling time which may be ~ 3 mins, the pump will continue to run because the demand for heat has not gone away.

"When the downstairs thermostat calls for heat - it tells the tado controller to open the DHW valve" do you mean the CH m.valve? The DHW valve is also controlled by the cyl stat.

Apologies yes - when the CH valve will open when downstairs calls for heat!

 

[John.g]

So, what tells the boiler to start when there is a call for DHW in high summer or anytime for that matter when all TRVs are shut?.

 

[stevedurban]

Doesn’t look like so you’ve had this problem for a while ?

“I added digital tado room stats about a year ago in the hope that it would help… alas it didn’t!”

Yes - I’ve had it for over a year - maybe 2. I’ve gone through cycles of trying to find a solution. Each plumber that came - serviced it and said - “it cold - so you use more heat! - and that was it! They didn’t really check anything - never checked the gas meter for usage per min etc… I just couldn’t find anyone with any drive to just confirm their theory! If it is just I’m using more gas - then so be it!

I just can’t understand why for 8years or so of living in the house - my estimated average gas usage on every bill has been 6-10,000 and a bill of around £120 a month (averaged over the year). I’m now heading to an average of 60,000 according to their estimations (185kwh today!)

 

[ShaunCorbs]

Only thing I can think is the tado is trying to heat the rooms often instead of a central room stat coming on once maybe twice an hour the tado is bring it on every 2-5 mins as the room temp fluctuates / drops

185x365 67k kWh so seems in the realm of correct

 

[stevedurban]

So, what tells the boiler to start when there is a call for DHW in high summer or anytime for that matter when all TRVs are shut?.

Tado had a schedule that tells the boiler when to be on. Before I used to have it on 24x7, but after our chats it’s now just 2 hours a day.

When tado tells the hot water to be “on” - the tank stat is then monitored and when the water drops below its Temp - it fires the boiler and Opens the valve.

 

[stevedurban]

Only thing I can think is the tado is trying to heat the rooms often instead of a central room stat coming on once maybe twice an hour the tado is bring it on every 2-5 mins as the room temp fluctuates / drops

185x365 67k kWh so seems in the realm of correct

185kwh x 365 days is 67525kwh. Is that a normal Amount? Maybe I have unrealistic views? Id checked online and it seemed to suggest around 10-15000 was average to high for a 4 bed house.

 

[John.g]

185kwh/17.5 heating hours is 10.6kwh/hr so one would expect to see very high room temperatures?

 

[stevedurban]

185kwh/17.5 heating hours is 10.6kwh/hr so one would expect to see very high room temperatures?

We have the rooms around 20/21 degrees max.

 

[ShaunCorbs]

185kwh x 365 days is 67525kwh. Is that a normal Amount? Maybe I have unrealistic views? Id checked online and it seemed to suggest around 10-15000 was average to high for a 4 bed house.

Depends how long you have the heating on/ your system

That figure will be for a dumb system eg central stat

 

[John.g]

Tado had a schedule that tells the boiler when to be on. Before I used to have it on 24x7, but after our chats it’s now just 2 hours a day.

When tado tells the hot water to be “on” - the tank stat is then monitored and when the water drops below its Temp - it fires the boiler and Opens the valve.

So once again back to square one with that huge usage last summer with no logical reason as there was no demand for CH.

 

[ShaunCorbs]

185kwh/17.5 heating hours is 10.6kwh/hr so one would expect to see very high room temperatures?

If the boiler is running at 24kw tho due to the flow being enough for high fire

 

[ShaunCorbs]

So once again back to square one with that huge usage last summer with no logical reason as there was no demand for CH.

Unless there was and the op didn’t notice ?

 

[stevedurban]

Tado had a schedule that tells the boiler when to be on. Before I used to have it on 24x7, but after our chats it’s now just 2 hours a day.

When tado tells the hot water to be “on” - the tank stat is then monitored and when the water drops below its Temp - it fires the boiler and Opens the valve.

Depends how long you have the heating on/ your system

That figure will be for a dumb system eg central stat

We sort of do have a central stat. There is only one stat that’s downstairs that can call for heat. It’s set to 21 degrees and is on from 6-9pm. The rest of the house is basically just TRV’s (the external thermostat just makes the TRV’s more efficient by sensing the temperature in the room - rather than the temperature on the TRV itself)