Replacing old Baxi floorstanding boiler with a HE Combi

[hammerswinger]

The boiler is on a programmer with the same operation times set as the old boiler had, the room stat is set to the same settings we used with the old boiler, in my book that's the same operation so I would think I should be seeing some reduced gas usage if the boiler is more efficient like they say it is.

So how else can I work out the efficiency savings I'm not getting


Cheers.

 

[Dan Robinson]

Turn it down a little.

Turn the thermostat down a little.

Get a better boiler.

Fit the weather compensation pack.

Get a programmable room thermostat,

Upgrade the insulation on your house.


Generally following the advise already given above.

 

[hammerswinger]

Doing any of what you have listed would then not be giving a fair comparison between the old & new boiler would it.
To conduct a fair test the operation parameters should remain the same.

I maintain that most of the efficiency ratings that are bandied around are are misleading, they will be achieved in laboratory conditions and aren't a true reflection of the efficiency of a boiler installed in the real world...as I said to start with...they're mumbo jumbo


Cheers.

 

[Dan Robinson]

I apologize. You obviously know far more than I do about modern boilers, their installation, configuration, specifications and use.

It is now obvious to me that the last 13 years of my career have been totally wasted and I shall as of next week begin the arduous task of refunding every penny if my I'll gotten gains.

What was I thinking?

Of course a boiler which uses more of its heat on the water is going to use the same amount of energy as one that pumps it into the atmosphere. This flue temperature readings and gas rates were all a conspiracy by Centrica and the government.


The laws of physics and basic common sense are vastly overrated anyway

 

[ALEC1]

boiler efficiency is not the same as system efficiency..amd system efficiency is greatly influenced by control strategy..


If the setpoint and return temperatures are both high then expect limited savings....

 

[hammerswinger]

I apologize. You obviously know far more than I do about modern boilers, their installation, configuration, specifications and use.

Well it appears so, doesn't it.... you're advising me to turn it down etc to make savings, so how can a fair comparison be achieved if the setting are different on the tests.

I maintain that the points raised in my last post are valid...you can't have a fair comparison if you start to alter boiler on times & room stat temperatures...just accept that instead of coming back with a load of waffle about wasting your time for the last 13 years etc, etc,...quite childish isn't it

 

[Dan Robinson]

If you are not using the new boiler the way it is supposed to be used then you won't get the savings. It really is that simple bleating on about fair comparisons is all well and good but only if it is a fair comparison.

Using a condensing boiler the same as an SE boiler is not fair as it is not working as designed.

Until you understand that very basic principle I am afraid you are on a hiding to nothing.

 

[hammerswinger]

 

[Dan Robinson]

I see you're struggling...

Think of it another way

You don't ride a two stroke 125 the same as a 4 stroke. They burn the same fuel, only differently. You still have the same roads and speed limits, just, you change year much lower down the rev range.

Now if you wish to carry on arguing black us white, start your own thread instead of ruining the OP's.

 

[tahir2]

Hey Dan

He isn't ruining it - some valid points, but we get the message now so that point is moot AFAIC.

However one thing, Hammerswing if the new boiler install is on for the same period and has the same or similar capacity as the previous boiler then Dan is going to be right.

The new boiler should hit its operating temperatures that bit quicker however and therefore you can change some of the settings to accommodate for that. Someone come in with a car analogy - always works when trying to describe how computers work (and break.) to some customers.

One thing this thread has done is given me a lot of information to digest. In the long run I would be better of changing the central heating and water heating system. My house faces West so no chance of solar water heating at any competitive and meaningful capacity. I also know I may not be staying at this property for more than 10 years but more likely to rent it out than sell it when the time comes - God willing. Have to look at some options for the winter, I hate wasting money but then is an overhaul to the system also a waste... I am inclined to believe it won't be right now.

Dan, the Intergas boilers can be had for approx £850 with flu and a kit to fit them, can't seem to find many online shops selling the Atmos. What do you think, should I go for it if you were in my position?

 

[Dan Robinson]

What HS is conveniently ignoring is the fact that condensing boilers should be run at lower temperatures for longer to be the most efficient.

Using it the same as his old boiler is just daft. Kind of like red lining a common rail turbo diesel and expecting it return the same mpg that it would if you shifted up at 2000 rpm. You don't over clock a PC and then complain it runs hotter than before.

Atmos sell the boilers direct or through the installer. They are not quite as cheap but in my experience the support is better. I am however going to IGUK soon to be able to offer the 5 year warranty so will see if experiences change.


If you are daan sarf, the sales chap is Len. Oop north it is Andy - who is occasionally on here.

If you are planning on renting out then Atmos or Intergas are ideal as they were designed for that market sector.

 

[hammerswinger]

All mud slinging aside I really don't thing the figures quoted by the manufactures are a true representation of a boiler working in the real world, no matter how you set it!

As Dan seems to be a frustrated motor engineer maybe he will understand the point I mad earlier, no matter how hard you try you will never achieve the MPG figures that the manufactures quote, it just won't happen, I believe exactly the same is true for boilers.

Anyway it's up to you to believe whatever you want, I don't believe for one minute that if you replace a 70% efficiency boiler with a 90% efficiency boiler you will ever see anywhere near a 20% saving no matter what devices or setting it has, and I think anyone who expects to see a 20% saving will be vastly disappointed.


Cheers.

 

[tahir2]

You may be right my friend, but as stated earlier there are a few other reasons for doing this as well.

I am going to think about it though and will make a decision carefully and slowly, someone called Kingston have made a microCHP boiler that is promising to be vastly less expensive than what we have on the market currently.

 

[Dan Robinson]

Good luck Tahir. That boiler looks interesting, but be cautious.

 

[ChrisR]

we replaced our old band G combi boiler (below 70% efficiency) & replaced it with a band A (above 90% efficiency) condensing combi 2 years ago, our usage has remained unchanged but the bills have not changed in the slightest!

That's not the usual experience. You've probably got something wrong in your system - could be anything. The standards among installers are highly variable, perhaps you should get someone else to look at yours.

20% saving (or more) when replacing an old cast iron lump with a condenser, is not unusual, but more than just the boiler is usually changed or fixed at the same time.
If not, then what's very common is that the husband says absolutely nothing's changed, and the wife says how much warmer she is with the new boiler... Correlate that with us all being told how one degree lower saves 10%.
You're right that some of the claims of some of the boiler manufacturers, and the odd installer, are misleading. There be dragons.

Tahir do make sure that whatever is installed, particularly in relation to its controls, is something you actually both understand and believe in. Understand, because your installer may not, and even by the manufacturer's own techies may not. And do believe in, just in case you fall in range of one of the companies or installers talking b01lox. Try asking for evidence - it's painfully thin on the ground.
If things don't work out for you as a user, then your control system may become one of the surprisingly large proportion of "clever" ones which are never set up right, or get maladjusted, disabled, or ripped out.

What I'd want in a house I live in is is very different from that in a house I rent out to student nurses. Horses and courses.