Real world testing example of Condensing Boiler in older home

[SJB060685]

No I don’t have LED lighting in my flat. Should definitely make the transition.

 

[John.g]

Haven't had time to tinker much with my heating system since. Just been running it as normal. Racked up 60 hours boiler thermostat call time on the BEM and it's showing an overall saving of 17.5%.

View attachment 73715

This is the average saving it does better on the upstairs than downstairs zone. Perhaps because running the upstairs the boiler is definitely oversized whereas it's just about right on the ground floor.

Still interested to carry out balancing when I get time. And to see if this new condensing boiler with BEM will get me through spring on 900L which would more than halve my regular winters oil bill!

Condensing is paramount to maximising efficiency. All oil boilers on the market today are condensing but for most oil boilers the similarities to their gas cousins stops there. The dew point for kerosene flue gases is a lot lower than mains gas. At ~ 47°c return temperature condensing will start but you are then relying on the secondary heat exchanger efficiency to make sure the water then returning to and through the primary heat exchanger is above dew point else you will get back end rot. There is ways to prevent this but it’s added parts, added cost and a bit of maths to make sure everything runs properly.
Gas boilers have higher dew point temperature but more importantly have the heat exchanger constructed of materials able to withstand lower water temperatures and not rot. The lower the return temperature can be the greater the level of condensing and therefore efficiency. Also gas modulating boilers are even more efficient at part load, whereas with oil you have to meet certain criteria on most boilers.
I know I’ve banged on about it a lot and I do apologise but the Sapphire boiler is an absolutely huge advancement in the oil world. Fully modulating, so can closely match the ever changing load with minimal cycling, excess fuel consumption and burner wear and tear.
For maximum efficiency you want good modulation and low flow temperatures. If a fixed rate burner like most oil burners I would consider a different system design approach to the common S and Y plans.

Worth a read.

Boiler Modulation: What is Boiler Modulation & Boiler Cycling

Discover the benefits of boiler modulation! Learn how boiler modulation optimises energy usage, increases efficiency, and reduces operating costs.

www.heatgeek.com

This trend (from the above) doesn't make a lot of sense though as it doesn't give the total cycle time(s)

 

[JC22024]

No I don’t have LED lighting in my flat. Should definitely make the transition.

I ended up going with warm white LED lights throughout the interior of my house. There are multiple studies out there indicating white LEDs may be detrimental to your health

Light Pollution - Human Health Impacts from LEDs

Light Pollution - Human Health Impacts from LEDs - Designing Buildings - Share your construction industry knowledge. A groundbreaking report released by the American Medical Association (AMA) Council on Science and Public Health affirms known and suspected impacts to human health and the...

www.designingbuildings.co.uk

In any case I also simply prefer warm lights anyway so it was an easy decision. And LEDs give out alot more light typically.

 

[SJB060685]

I ended up going with warm white LED lights throughout the interior of my house. There are multiple studies out there indicating white LEDs may be detrimental to your health

Light Pollution - Human Health Impacts from LEDs

Light Pollution - Human Health Impacts from LEDs - Designing Buildings - Share your construction industry knowledge. A groundbreaking report released by the American Medical Association (AMA) Council on Science and Public Health affirms known and suspected impacts to human health and the...

www.designingbuildings.co.uk

In any case I also simply prefer warm lights anyway so it was an easy decision. And LEDs give out alot more light typically.

So avoid white LED’s?

 

[SJB060685]

Worth a read.

Boiler Modulation: What is Boiler Modulation & Boiler Cycling

Discover the benefits of boiler modulation! Learn how boiler modulation optimises energy usage, increases efficiency, and reduces operating costs.

www.heatgeek.com

This trend (from the above) doesn't make a lot of sense though as it doesn't give the total cycle time(s)
View attachment 74117

Several of us on this forum have done the Hest Geek course . A subject discussed on their website quite a lot.

 

[JC22024]

So avoid white LED’s?

Yes I think for a dwelling it is best to avoid white LEDs personally. For Offices and Commercial uses White are great however.

2700 - 3000k is what I aim for.

I do have a pre payment type Electricity Meter in my house. Electricity prices went up here in Jan. But before they did I topped up £300. For only two of us in the house we tend to go through alot of electricity..... depite using delay settings on washing machines at night etc too on the cheaper economy 7 rate.

I had about 50% of my house on LED lights until recently. Then I updated the remaining bulbs to all LED warm white. Some rooms like the hallway had alot of bulbs so the 90% savings multiplied by over 10 bulbs would add up.

And certainly knowing how much we normally consume and checking the meter reading since (Which is just a £ remaing figure in a small display in the Kitchen) it appears swapping the remaining bulbs and probably the ones that get the most use has made a marked imrovement in savings. More than I would have thought I mean. Will know better after a few months and when doing Tax return (Which makes me go through utility bills) but could be saving 50p per day.

 

[Chuck]

I ended up going with warm white LED lights throughout the interior of my house.

About four or five years ago, after some experimenting with types and makes I went for Philips 2700K LEDs throughout and they're great. In a couple of places I have the dimable ones and these reduce the colour temperature as you dim them (getting a touch more orange at lower levels), which is a nice touch. The whole exercise paid for itself in about 12-18 months.

I'd strongly recommend you only choose between traditional brands (Philips, Osram, etc.) because the cheaper 'own brand', eBay, etc. samples proved to have a bad colour spectrum, be unreliable and, in one case, dangerous.

 

[JC22024]

I just purchased one of these smart Oil level monitors. It can determine the estimated run out date and chart oil Consumption trends. Will install it Saturday evening and see how it does over the next while. Much more reliable than depending on myself to look into the tank!

 

[JC22024]

The sensit is up and running, pretty good the way it can record and chart data and try to anticipate run out date. Weekly email reports can be generated etc detailing the exact litres in the tank for records.

 

[Ric2013]

Hi @JC22024 again. I've been reading through a printed-out copy of this thread and regarding post #92, I feel a need to correct your misunderstanding of how smart pumps generally work. A proportional pressure pump (including Grundfos Autoadapt) seeks to keep the pressure drop constant across the radiators. It very slightly drops the pressure as TRVs close to try to compensate for the decreased pressure losses across the boiler primaries (so there is some truth in your understanding) but one TRV shutting should not cause other radiators to fall dead. It does not drop the pressure very much. Conversely, a 'dumb' pump cannot help but increase its pressure as TRVs throttle down, thus forcing more flow through any TRVs that remain partially open, sometime resulting in whistling. They (smart pumps) aren't without issues, particularly as the conventional automatic bypass valves often fitted to heating systems rely on an increase in pressure to open up as TRVs are shutting down.

Constant pressure will keep the pressure constant across the boiler (but not compensate for the primaries: that's the difference, plus CP is usually a much higher pressure setting).

The way most smart pumps do this is by monitoring power consumption to get an idea of how much drag is being created and then varying the speed of the impeller. Unlike the older pumps which ran at a fixed speed.

I've balanced my own house before and after replacing a pump. The new pump has proportional pressure and I thought I'd give it a go. It actually made balancing MUCH easier as, when I throttled back one radiator, that didn't then result in an increase in pressure and hence flow to the remaining radiators. So instead of going around the house several times tweaking as I went, I only really needed a couple of passes.

Re post #152, I wonder if you could help me follow your explanation better? Please let me know if I follow your understanding correctly or not... you say you think the Vector BEM works by allowing the boiler to first run to temp [i.e. until the boiler cuts out on its internal thermostat?] and then, [when the boiler decides to re-fire?] slightly delays [the next firing up of the boiler?] and then continues doing this while also monitoring the run time and stat call time? Which stat are we discussing? Room stat, I assume?

Are you saying that your understanding is that the BEM is monitoring the boiler duty cycle and delaying the boiler from firing for progressively longer times until it notices that this is reducing the system's ability to get the room temperature up to the required temperature? I'm struggling to get my head around how this works, but it would be interesting to be able to do so.

Thank you.

 

[JC22024]

Hi @JC22024 again. I've been reading through a printed-out copy of this thread and regarding post #92, I feel a need to correct your misunderstanding of how smart pumps generally work. A proportional pressure pump (including Grundfos Autoadapt) seeks to keep the pressure drop constant across the radiators. It very slightly drops the pressure as TRVs close to try to compensate for the decreased pressure losses across the boiler primaries (so there is some truth in your understanding) but one TRV shutting should not cause other radiators to fall dead. It does not drop the pressure very much. Conversely, a 'dumb' pump cannot help but increase its pressure as TRVs throttle down, thus forcing more flow through any TRVs that remain partially open, sometime resulting in whistling. They (smart pumps) aren't without issues, particularly as the conventional automatic bypass valves often fitted to heating systems rely on an increase in pressure to open up as TRVs are shutting down.

Constant pressure will keep the pressure constant across the boiler (but not compensate for the primaries: that's the difference, plus CP is usually a much higher pressure setting).

The way most smart pumps do this is by monitoring power consumption to get an idea of how much drag is being created and then varying the speed of the impeller. Unlike the older pumps which ran at a fixed speed.

I've balanced my own house before and after replacing a pump. The new pump has proportional pressure and I thought I'd give it a go. It actually made balancing MUCH easier as, when I throttled back one radiator, that didn't then result in an increase in pressure and hence flow to the remaining radiators. So instead of going around the house several times tweaking as I went, I only really needed a couple of passes.

Re post #152, I wonder if you could help me follow your explanation better? Please let me know if I follow your understanding correctly or not... you say you think the Vector BEM works by allowing the boiler to first run to temp [i.e. until the boiler cuts out on its internal thermostat?] and then, [when the boiler decides to re-fire?] slightly delays [the next firing up of the boiler?] and then continues doing this while also monitoring the run time and stat call time? Which stat are we discussing? Room stat, I assume?

Are you saying that your understanding is that the BEM is monitoring the boiler duty cycle and delaying the boiler from firing for progressively longer times until it notices that this is reducing the system's ability to get the room temperature up to the required temperature? I'm struggling to get my head around how this works, but it would be interesting to be able to do so.

Thank you.

Thanks for that, yes I would agree I don't fully understand the Smart Pumps! Its quite likely my Grundfoss one was faulty too. The regular type pump has been fantastic so far so I don't need to test the pumps any further but no doubt smart pumps have advantages yes.

Ref the BEM, it only has 2no inputs.

1st input is a live feed which is the boiler call signal. Aka the live feed from the room stats which powers the boiler and pump in my conventional system.

2nd input Is from the call side of the boiler thermostat.

That's it. It has no other sensors or data from indoor or outdoor temperatures.

First time the boiler fires up for the day the BEM gets its power feed and starts and also sees how the boiler is firing until the boiler thermostat is satisfied and shuts off. BEM is still live and monitoring from the boiler call feed. Then the boiler stat begins to call again and the BEM delays the burner from firing for a short time then let's it fire until the boiler stat is fully satisfied once more. Watch the video below to see this cycle:


The BEM continues to monitor and log the boiler firing cycles and delaying them more and more until it is effectively matching the system demand over time. (At least this is my understanding of it) Then once the room thermostat / heating call signal stops the BEM and boiler stops and will start from scratch again the next time heating is fired up.

What I like about this particular one is it always let's the boiler thermostat fully satisfy and turn off before it then delays it firing up again. Therefore the comfort inside the house is unaffected as the water temperature does reach full stat just that it will be dropping lower in between boiler firing cycles.

What I will say thinking about this more in recent weeks is the clocks it is showing are accurate in that it is recording boiler stat call time and the boiler burner time (which it reduces) but it's not really accurate to say this is a xx% saving in oil.

Its more of a meter showing how much it has delayed the burner. So the % of oil saved is lower than what the clocks state but it is definitely reducing the boiler cycling as much as practical so this is its main purpose and advantage.

 

[SJB060685]

@Ric2013 your comments about PP and CP are bang on, so no need to elaborate further there.

With regards to the controller it does exactly how you picture it and is actually quite an intelligent and sophisticated unit.
The heat source in question is an oil boiler and as I’m sure you are aware 99% of domestic oil boilers currently installed are fixed rate output (there are now a couple boilers on the market that one fully modulates and the other is a two stage burner).
The problem with fixed rate burners is unless the outdoor temperature is at design temperature (say -2°c, depends on location) then a fixed rate burner will always cycle and the warmer it is outside the greater this cycling is. This particular unit will monitor and I assume learn these cycle rates and prevent unnecessary firing cycles. Let’s say it’s a 20 kw load at -2°c and a target room temperature of 20°c but the outside temperature is 11°c. You now only require half the output and you would find the burner will run for say 5 minutes and off for 5 minutes while maintaining your internal temperature. The problem is though during that burner off period the flow sensor will notice a drop in temperature and bring the burner on while the rooms are at temperature and try’s closed. This then only circulated water through a bypass or heat sink, the water doesn’t displace any energy and in turn the boiler cycles more. Constant stop starts for any heat source are not good and I know you know why. This unit can minimise this cycling, not only saving fuel but also extending the life of burner components.