Any way of monitoring boiler firing time?

[Ric2013]

Was just thinking about ways of monitoring heating system efficiency and the effect of different ways of using the house, what doors and windows are open at what times and the effect of various weather on gas consumption. We can do it for electricity at a household level, but it's fairly obvious how to save electric. The solutions to reducing heat losses are not so obvious except for the very obvious one of not heating at all.

Unfortunately, since the gas cooker is used extensively, the gas meter is not a wholly valid way of measuring gas consumption as you cannot know how much has gone through the boiler. In fairness, the cooker does release some heat into the room... but, if nothing else, the fact that the gas meter is outside means it is not a practical point of measurement.

It has occurred to me that measuring boiler firing time would have a near-perfect correlation with heat input (on an old boiler that cannot modulate).

But the simple way I can think of doing this would be to piggy-back a run-hour meter off the boiler gas valve switched live which could be accessed without removing the combustion casing (which would essentially impose an additional load on the boiler circuitry, albeit minimal, and could therefore possibly (?) count as a boiler modification even though you would not actually be changing the boiler control method in any way).

A clamp-type ammeter around the gas valve switched live could be used instead. This could be one of the early electrical energy use monitors that pre-dated smart meters. This way all you would be doing would be measuring electrical current flow to the gas valve and the energy use monitor would give a reading in watthours that could be used to calculate run hours. This might be too bulky to be able to fit.

Finally, if there were some way of logging the blue flame through the peep-hole on the front of the boiler casing, that would give a run-hour reading. Perhaps a light dependent resistor switched transister circuit connected to a battery power source and switching a relay to run a runhour meter. Bulky and messy though.

The first one would be neater, simpler, less complicated and reliable. But would it be legal?

Or has someone got any clever idea that is neat and clean and that I've not thought of?

 

[ShaunCorbs]

Viessmann 200s tell you the load and burn time summary but will require a boiler change 😀

 

[centralheatking]

Very soon there will be available domestic BMS...building management systems... I know because we are involved..initially for social housing but it will universal not long after.
These units will monitor most aspects of a domestic building...eg temp, humidity, gas, water and electricity use. at various places in the property they will also talk to the domestic appliances and see how they are performing and then crucially compare at the monitoring centre each place with others on the system and alert operators and owners to unusual readings. eg say your boiler is drawing a little too much power for the fan exhaust ..an indication of a motor on the way out..the centre will call or alert you and send an engineer before it burns out. JCB and Caterpillar already listen to their plant world wide and if eg a crawler shows is unhappy they call the operator and get the unit closed down to avoid premature damage to the unit, pending a service visit. A number of large housing trusts are well advanced with this already we have to play along just to keep up. centralheatking

 

[garygvl]

your just over thinking things.

 

[Darren Jackson]

Get an engineer round to gas rate your boiler. That will tell you the kW/hr being used by the boiler and the consumption m3/hr or ft3/hr. It will only take 10mins to test.

 

[Ric2013]

Get an engineer round to gas rate your boiler. That will tell you the kW/hr being used by the boiler and the consumption m3/hr or ft3/hr. It will only take 10mins to test.

I don't have a problem with knowing what the gas rate is. Think it's on the paperwork somewhere from last time the boiler was serviced but in any case it's simple enough to get the boiler to fire for 15 minutes flat without using the cooker and then read the meter, multiply by 4 and you have your cu m/hr.

What I would like to be able to measure is the amount of time the boiler is actually firing for. As the boiler was sized before the house was better insulated, for a higher room temperature than is actually being required, for DHW which isn't constantly being produced, before TRVs were fitted, and for (presumably) -1°EAT, most of the time it is well oversized for the demand that is actually required of it. As such, like most boilers, it cycles even when in use. Thus gas rate is only useful if we know the run time.

 

[centralheatking]

I don't have a problem with knowing what the gas rate is. Think it's on the paperwork somewhere from last time the boiler was serviced but in any case it's simple enough to get the boiler to fire for 15 minutes flat without using the cooker and then read the meter, multiply by 4 and you have your cu m/hr.

What I would like to be able to measure is the amount of time the boiler is actually firing for. As the boiler was sized before the house was better insulated, for a higher room temperature than is actually being required, for DHW which isn't constantly being produced, before TRVs were fitted, and for (presumably) -1°EAT, most of the time it is well oversized for the demand that is actually required of it. As such, like most boilers, it cycles even when in use. Thus gas rate is only useful if we know the run time.

Simple solutions are often best, why dont you video it, the video will record time and the idiot lights on the boiler will tell what its up to. centralheatking

 

[Chalked]

Just because the boiler is on, does not mean it’s firing on full. A 24 kw boiler can modulate down to 2.4kw.
put your effort into insulating your house as well as possible. Then your boiler will work less.

 

[Ric2013]

Simple solutions are often best, why dont you video it, the video will record time and the idiot lights on the boiler will tell what its up to. centralheatking

Because to video the boiler pilot light (no electrical lights on this boiler) over the course of a day would exceed the battery life of the camera, and it would be very labour intensive to get a statistic from 12 hours of filming. But I like the concept.
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Just because the boiler is on, does not mean it’s firing on full. A 24 kw boiler can modulate down to 2.4kw.
put your effort into insulating your house as well as possible. Then your boiler will work less.

'On an old boiler that doesn't modulate' !!!

In any case, I think you misunderstand why I want to do this.

The insulation is already as good as it's going to get for the foreseeable future so I'm more interested in monitoring boiler usage, what the boiler is actually doing over the course of a day, and over the course of the season.

 

[ShaunCorbs]

If your that way (electronics) you could figure something out with a raspberry pi and you could use the flame sensor as your trigger that would be able to record times etc

 

[Scott_D]

Nest tells you number of hours the heating is on and sends a monthly report
The ideal vogue logs burner hours.
I think vaillant does as well.

 

[Ric2013]

If your that way (electronics) you could figure something out with a raspberry pi and you could use the flame sensor as your trigger that would be able to record times etc

That's an idea, Shaun. I'm wondering what you think the advantage would be over a simple mechanical run-hour counter (£15) would be. Other, I suppose, than the fact that you could set up readings to be taken automatically rather than be limited to whatever readings you can take (which would require me to be in all day to write down the readings).

 

[bacon_sandwich]

Does the boiler heat the hot water as well ? - if not i would simply put the hour meter on the call for heat wire

 

[ShaunCorbs]

That's an idea, Shaun. I'm wondering what you think the advantage would be over a simple mechanical run-hour counter (£15) would be. Other, I suppose, than the fact that you could set up readings to be taken automatically rather than be limited to whatever readings you can take (which would require me to be in all day to write down the readings).

Other than a fancy graph and a dc read out nothing if you can put the dial meter in easily go for that simple

 

[centralheatking]

If your that way (electronics) you could figure something out with a raspberry pi and you could use the flame sensor as your trigger that would be able to record times etc

those pie things are really quite cheap and very adaptable chking we have mucked about with them for past 2..3 years dead cheap and will do loads of things..its not my forte but my boys
know what to do...I spec what I want it to do they play ..chking

 

[Ric2013]

Does the boiler heat the hot water as well ? - if not i would simply put the hour meter on the call for heat wire

Yes, it's a heat-only boiler. In any case, the call for heat wire would show when heat is required, not when the boiler is actually burning gas. I'm not splitting hairs with this: often the boiler is running at less than a 50% duty cycle.
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those pie things are really quite cheap and very adaptable chking

I must say I'm tempted to buy one, having looked at some of what is available. Not done much with a computer since I was a teenager and playing around with BASIC, but if you can easily get sensors to actually make the raspberry pi interact with the real-world, that could be interesting. It was always my thought that even BASIC would allow you to control and monitor quite a lot with simple programming, but the computers I had at the time had no way of interaction save what you could input manually using the keyboard or what you could read off the screen.

 

[ShaunCorbs]

Yes, it's a heat-only boiler. In any case, the call for heat wire would show when heat is required, not when the boiler is actually burning gas. I'm not splitting hairs with this: often the boiler is running at less than a 50% duty cycle.
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I must say I'm tempted to buy one, having looked at some of what is available. Not done much with a computer since I was a teenager and playing around with BASIC, but if you can easily get sensors to actually make the raspberry pi interact with the real-world, that could be interesting. It was always my thought that even BASIC would allow you to control and monitor quite a lot with simple programming, but the computers I had at the time had no way of interaction save what you could input manually using the keyboard or what you could read off the screen.

Link the mechanical counter into the fan feed if it’s 240v

 

[Chuck]

but it's fairly obvious how to save electric.

Same goes for gas: (a) reduce the time-averaged setting of your thermostat(s), (b) improve insulation, (c) reduce ventillation.

The other things that affect fuel consumption significantly (solar gain, cloud cover, air temperature, wind-chill, ground temperature) aren't controllable so measuring process variables isn't going to help you much.

 

[bacon_sandwich]

*ugger it, get hold of an old U6 meter and pipe it in 😛

 

[Ric2013]

Link the mechanical counter into the fan feed if it’s 240v

That is a brilliant idea. The fan takes more current than the gas valve, so the slight extra electrical load on the relay in the circuit board is likely to be less significant.

I've actually got a clamp on energy monitor courtesy of Essex Libraries (only person to take it out for ten years and they have several, so I can renew it as much as I want) that just about fits under the plastic electrical enclosure and over the white wire to the gas valve. Reads 4W when the gas is alight and keeps a daily total in Wh, so it will do for now. May not be entirely accurate as we don't know if the gas valve uses 3.6 or 4.4W or anywhere in between, but it should be consistent.

At least now it should be easy to work out if the boiler temperature has any effect, best time of day to air the house, etc etc. As Chuck says, several variables, but could be interesting not to change behaviour at all and see what effect the weather has - how much effect the wind has (used to be significant, but the house is now much less leaky... downstairs anyway).

*ugger it, get hold of an old U6 meter and pipe it in 😛

That is a great idea but, when I tried to take the neighbour's meter, the guy from the gas board started to do the meter readings in this road and I had to put it back pretty sharp and hide behind a conveniently located shrub. I didn't even have time to empty the box of 50p pieces 🙁