High gas usage for boiler.

[stevedurban]

Ok then, the flow pipe from the boiler should be absolutely scalding and you should only be able to touch it for a very short time.

Yes - scalding hot

Not sure if it’s right - but both sides of the ABV are also scalding.

(Hot pipes in red!)

 

[John.g]

They certainly shouldn,t especially when the index is set to 0.5? (5M), there may be a bit of crap under the seat, with the boiler running slowly, adjust (anti clockwise) the setting knob, you should hear some noise if the ABV starts opening at ~ 0.3/0.4, then reset it back to 0.5.
If it is in fact passing badly, the boiler return should also be very hot.

 

[stevedurban]

They certainly shouldn,t especially when the index is set to 0.5? (5M), there may be a bit of crap under the seat, with the boiler running slowly, adjust (anti clockwise) the setting knob, you should hear some noise if the ABV starts opening at ~ 0.3/0.4, then reset it back to 0.5.
If it is in fact passing badly, the boiler return should also be very hot.

They certainly shouldn,t especially when the index is set to 0.5? (5M), there may be a bit of crap under the seat, with the boiler running slowly, adjust (anti clockwise) the setting knob, you should hear some noise if the ABV starts opening at ~ 0.3/0.4, then reset it back to 0.5.
If it is in fact passing badly, the boiler return should also be very hot.

So I just tested as described. The tank was calling for heat. I adjusted the abv to around 0.3 and no different sounds. When the tank stopped calling - I could hear a new sound which was obviously water going through the abv - I’ve never heard this noise before.

I thought the idea of the abv was that when the boiler ran and then stopped calling for heat - and the valves closed - the water should pass through the abv to allow the pump to slow without excess pressure on the pump? If the abv was doing it’s job (and there isn’t another one in the boiler) then I should have been hearing that sound every time both valves just closed?

 

[stevedurban]

Can you see the actual boiler temperature from the boiler display to confirm that the high setting 0f 6+ is actually reflected in the boiler temperature.
Also, as suggested above, turn the cylinder stat up if the motorized valve is shut and ensure it opens and turn it down if the motorized valve is open and ensure it shuts.
If the boiler temperature is as high as it might be, 75C+, and if the DHW temperature doesn't feel scalding then a fair indication that its temperature is being controlled to its setpoint of 50C. (should really be 60C, for legionella protection).

Just to confirm - I set the tank stat to 60 - and after a while tested the water temp of the nearest tap - and it was 59.9

 

[John.g]

It was probably never set up properly, you are possibly the first person to touch it, if the no flow pump head is less than 5M (0.5bar) then the ABV will never open, so you can adjust it around that setting (of 0.3) so that it only opens when both mot.valves shut and the pump is on overrun.

Just to confirm - I set the tank stat to 60 - and after a while tested the water temp of the nearest tap - and it was 59.9

Well, back to square one so re high gas consumption as the cyl temp is being controlled and even if left enabled all day shouldn't account for that excess gas usage which was mad during the summer , see post #31, even 12kw current usage seems quite high once house up to temp?.
You said you might try running on the immersion for a day or two to rule out HW usage?.
Can you also not programme the HW cylinder to be heated for a few hours in the morning?, can't remember if you said that it has its own programmed zone.

If the ABV is passing then that will consume a fair few M3 of gas via unlagged copper pipes, the easiest way to check it is when/if the system is cold in the morning and just after the boiler fires up, keep your hand on the vertical ABC (downstream) pipe which should remain cold for a long period, if not leaking it could still possibly feel very hot due to conduction.

 

[ShaunCorbs]

Abv is shot by the sounds of it as it shouldn’t be passing when the system is on / running

 

[stevedurban]

It was probably never set up properly, you are possibly the first person to touch it, if the no flow pump head is less than 5M (0.5bar) then the ABV will never open, so you can adjust it around that setting (of 0.3) so that it only opens when both mot.valves shut and the pump is on overrun.


Well, back to square one so re high gas consumption as the cyl temp is being controlled and even if left enabled all day shouldn't account for that excess gas usage which was mad during the summer , see post #31, even 12kw current usage seems quite high once house up to temp?.
You said you might try running on the immersion for a day or two to rule out HW usage?.
Can you also not programme the HW cylinder to be heated for a few hours in the morning?, can't remember if you said that it has its own programmed zone.

If the ABV is passing then that will consume a fair few M3 of gas via unlagged copper pipes, the easiest way to check it is when/if the system is cold in the morning and just after the boiler fires up, keep your hand on the vertical ABC (downstream) pipe which should remain cold for a long period, if not leaking it could still possibly feel very hot due to conduction.

So for the past 3 days I’ve set tado to only turn the heating on for 2 hours a day (11-1) - and the usage hasn’t changed. I also checked when it was off that turning the tank stat up didn’t call for heat and open the dhw valve - and it didn’t - so we know that’s off.

Today upto 6pm so far I’ve used 148kwh!! It’s crazy!!! There has to be something wrong somewhere!! Just not sure where to turn!!

On the abv pipes - it’s only a short way to the return pipe coming out the tank - so that pipe always seems to be hot (rightly or wrongly?)

If the HW is off - should any heat be coming out that pipe from the tank? Or is the fact it’s hot either a fault or the ABV working?

 

[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?.

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

 

[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?.

No sure what you mean about 3x2? Heating comes on at 6am - and goes off at 9pm. Water is heated only 11-2

I will be able to see half hourly reports from octopus energy tomorrow as the smart meter uploads each night.

I can see yesterdays report already. It seems to be about .7m3/hour From 6.30am-12pm. It doesn’t seem to peak between 11-2 (the water was on that setting already yesterday!)

As for the ABV - It’s piped before the valves - so that seems right! It seems to overrun for about 5 mins when the valves shut.

 

[ShaunCorbs]

Turn heating and hot water heating off and see what your software registers

Boiler shouldn’t fire at all when everything is set to off

 

[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)

 

[stevedurban]

Unless there was and the op didn’t notice ?

Let’s say I didn’t notice (very possible) - and the heating was on. It wouldn’t be higher than 21 degrees as the TRV’s and thermostats would have controller it) and with the hotter weather outside - it shouldn’t have taken much time keep the house at that temperature. So it still wouldn’t really explain?

 

[ShaunCorbs]

And there not conflicting with each other eg trvs shut down but stat still calling ?

 

[ShaunCorbs]

Let’s say I didn’t notice (very possible) - and the heating was on. It wouldn’t be higher than 21 degrees as the TRV’s and thermostats would have controller it) and with the hotter weather outside - it shouldn’t have taken much time keep the house at that temperature. So it still wouldn’t really explain?

Depends what time you have it set for off ?

 

[ShaunCorbs]

It might be worth converting the system back to a dumb one for a month and see the usage as Jan and feb are normally similar

 

[John.g]

I would expect a "normal" house to need ~ 5/6 kwr/hr to keep it at 21C so 17.5hras @ 6 = 105kwh/day, i heat mine over the last few days 16 hr days for ~ 75/90kwh BUT my (4) bedrooms are kept at 16/18C, all downstairs kept at 21/22C.

 

[ShaunCorbs]

Plus hot water at around 30kwh ish as depending on usage

 

[stevedurban]

Depends what time you have it set for off ?

And there not conflicting with each other eg trvs shut down but stat still calling ?

Heating always goes off at 9

It’s possible - although I’ve tested time and time again with the downstairs stat. Pushing to 25 degrees and the ch valve opens - putting it to 5 degrees - it closes. I’ve never seen it not do it! But it’s possible it malfunctioned - but I guess the questions is:

The house was 17.9 degrees at 6am this morning before the heating came on. It was set to 21 degrees and we were in all day. It used 185kwh to try and keep it at 21 degrees. If that’s to get expected - then your view of “I just use more gas” could be right?

 

[John.g]

Dumb can be the smartest in the end as long as you don't need room temp control to the nearest 0.1 or 0.2C.

 

[John.g]

How many rooms are you maintaining at 21C, the whole house?.

 

[ShaunCorbs]

Dumb can be the smartest in the end as long as you don't need room temp control to the nearest 0.1 or 0.2C.

That I think is the problem each room has its own stat that’s opening and shutting prob 1-2 degrees and firing the boiler up for maybe 5 mins each time