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New Gas Boiler? Hot water priority, weather comp...

gavreid

Pretty Words...
OK, done to death. However, is there a good case for installing a new boiler with weather compensation on hot water priority and, possibly, with a view to adding a heat pump in addition in the future?

My WB system boiler is on an S plan plus and is 16 years only. My feeling is that learning to live with higher prices means turning down the thermostat. The boiler then cycles most of the time and runs inefficiently. Am I on the right lines or just leave the boiler until it breaks?
 
I've given mine a good flush and set up Honeywell home on it with tank sensor and wireless TRVs which is already saving a bit.

Twin pumps and valves so the HW and CH are potentially isolated from each other.

You can then add sensors to set the boiler cycling criteria. Set mine to target 60C but only switch on under 50C for the moment.

With the price of electricity i'd look after your old boiler as long as possible.

Haven't delved into the weather compensation yet as we have very irregular routines.

Blocking unused chimneys is the next job before we turn the heating on.
 
From my own experience of just over two years covering two Winters. Yes.

We had a weather compensated system installed and radiators fitted with zone temperature controllers i.e. each radiator has its own temperature setting and for different times of the day. If used correctly (my wife says that she is warm but the radiators are cold) you save on gas. In our case with 18 radiators the Winter gas bills are about 40% lower.

My wife also likes that she can adjust the temp in her 'office' using her smart phone.

The old system even with TVRs we tended to boil or freeze but with the new system we are always warm.

DV
 
Just had daughter round and she's had the £400 credit. They'd done the usual overestimate all summer so now faced with £6 per month until April!
 
Just had daughter round and she's had the £400 credit. They'd done the usual overestimate all summer so now faced with £6 per month until April!

Presumably only £66 of it, as it's either £66 or £67 per month off DDs until April. I'm waiting for my £98 to be reduced to £32. Not quite your daughter's £5 but I do have a reasonable credit built up which should cancel out costs Oct. to March.

Just had third and final quote for heat only boiler (top Vaillant or Ideal), big stainless steel cylinder, new rad and lots of bits 'n' bobs. Four grand (no VAT) All highly itemised so I can see how that figure mounts up. Previous two quotes were missing things out (one with and one without VAT) and confusing so I reckon it's a good deal
 
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My vote goes to Vaillant. Replaced my ancient (maybe 20 year old) Baxi boiler with a Vaillant condensing model 6 or so years ago and there was an immediate, and very noticeable improvement in the warmth of my house (using the exact same thermostat settings). No noticeably higher energy bills either. Cost me three grand all in, but really wished that I’d done it earlier.
 
When I replaced my old Vokera combi boiler at my old house a couple of years ago for a condensing combi boiler I saved well over 20% on my gas bill and had a more even temp around the house due to TRV and I am sure that could be improved on with a smart thermostat etc. Will be interesting to see how the condensing combi in my new home fares.
 
16 years old? It's going to die soon. I'd be doing the research now. Mine failed 2 years ago at, you guessed it, 16 years old, £500 repair bill or replace. In November. No pressure then. I was in full time work with no time to do the arithmetic. So do the sums now.
 
My vote goes to Vaillant. Replaced my ancient (maybe 20 year old) Baxi boiler with a Vaillant condensing model 6 or so years ago and there was an immediate, and very noticeable improvement in the warmth of my house (using the exact same thermostat settings). No noticeably higher energy bills either. Cost me three grand all in, but really wished that I’d done it earlier.

I think you have to use Vaillant controls to get all of the features though. The controls, not the boilers, have a reputation for being poor and expensive
 
My WB system boiler is on an S plan plus and is 16 years only. My feeling is that learning to live with higher prices means turning down the thermostat. The boiler then cycles most of the time and runs inefficiently.

When I looked into it (for a new boiler), the efficiency savings of modulating thermostats isn't that huge compared to on/off (assuming condensing boilers). I Googled just now and up to 10% possible. What you can do in the meantime is turn down the temperature knob on the boiler when the heating is on. Then turn it up for the water. Only takes a second. Won't save huge amounts, but boiler should cycle less if on lower temperature.
 
When I looked into it (for a new boiler), the efficiency savings of modulating thermostats isn't that huge compared to on/off (assuming condensing boilers). I Googled just now and up to 10% possible. What you can do in the meantime is turn down the temperature knob on the boiler when the heating is on. Then turn it up for the water. Only takes a second. Won't save huge amounts, but boiler should cycle less if on lower temperature.

Yes you only need about 10 kW at the most to heat a house but the boiler is vastly over-rated powerwise so it can't ever run efficiently - or so I think anyway. Some modern boilers can be triggered at two different power outputs it seems
 
Ah, yes. That is different matter. A boiler will modulate and will have a minimum output as well as a maximum output. If the minimum output is too high for the system, the boiler will cycle. Again, probably won't save huge amounts, but a lower minimum output allows no cycling. Boiler will run constantly, including on a low temperature.
 
Yes you only need about 10 kW at the most to heat a house but the boiler is vastly over-rated powerwise so it can't ever run efficiently - or so I think anyway. Some modern boilers can be triggered at two different power outputs it seems

The boiler can be range rated Gav ie fan turned down to suit the heating load of the house but unfortunately you need to have the boiler running full pelt to heat the cylinder so with heat only boilers you can’t have two different modulation points ie fan speeds.

I did a Vokera course online the other night and they were talking about this, I wasn’t really paying attention as I only install combis however they did say that you can buy accessories which makes the boiler do the two modulation thing also I think they also said that their commercial boilers do the double modulation thing and even triple modulation to run heat pumps and the like under floor circuits/zones and cylinders.

Apparently Vokera boilers for the European markets are all set up for multiple modulation.


Having said all of that I really don’t think range rating is that important vis efficiency and I asked them about that and they kind of agreed cause you really can’t stop boiler cycling you can only reduce it Vokera uses an anti-cycling timer to restrict the gas valve from opening fully at first fire up ie the boiler runs at 60% output for the first 15 minutes then ramps up by about 10% every fifteen minutes until the room thermostat is satisfied.

Haven’t read the entire thread but insulation insulation insulation.

Tony
 
which has a report this month on boilers . well worth a read . WB first and vaillant second . As you probably know i am a huge fan of Vaillant for their brilliant service . Had 3 vaillant boilers fitted in past 2 years
 
which has a report this month on boilers . well worth a read . WB first and vaillant second .

These 'best recommended boiler' lists do tend to change. The ones I've recently accessed on Google has Viessmann no.1 with Alpha (never heard of them) 2nd, Ideal 3rd, WB 4th and Vaillant 5th with recommended service note on W B and Baxi (6th).

Having had a 13 y.o. Vaillant combi in a previous flat, I do like them but Ideal are cheaper and also recommended (or were). My plumber can get V. Eco heat only immediately but there's a wait of a few weeks on Ideal. Odd.
 
Viessmann is what you want. You can either have a system boiler using their 4 pipe system which will give you full temperature for the hot water priority and then with work weather comp for the heating (100-W or if you want the best a 200-W) or the other option is their heat only boiler that you can add the optional weather comp sensor and cylinder demand box which will give hot water priority with more conventional motorised valves.
 
which has a report this month on boilers . well worth a read . WB first and vaillant second . As you probably know i am a huge fan of Vaillant for their brilliant service . Had 3 vaillant boilers fitted in past 2 years

Most professionals think there’s something going on between Which? And Worcester.
Worcester have the best marketing dept in the business
 


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