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

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.

That's where I'm leaning I think but spares can be very dear I understand
 
Thanks guys. Thanks @twotone. Nobody commented on the possibility of combining a gas boiler with a heat pump in the future. Is that a thing?
 
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

I have a 4 year old Vaillant with their vSmart thermostat and am mostly very happy with it. I switched off the weather compensation function as some days it was coming on at what I thought was very early. The modulation function works well and can run the boiler at very low power levels and the app is very useful. The vSmart thermostat costs about the same as a hive unit but does add the modulation function.

vsmart_pic by Mark Edwards, on Flickr
 
The vSmart thermostat costs about the same as a hive unit but does add the modulation function.

I heard that covid saw off production of some of the controls so prices mushroomed - they have/had a reputation for being opaque too in the various menu settings.
 
That's where I'm leaning I think but spares can be very dear I understand

Yep £450 for PCBs on some models but if there's a long warranty then that's not really an issue.

Personally I wouldn't buy a Viesmenn product customer service isn't great and hardly anyone fixes thier boilers.

Go with Worcester Bosch Gav, they might not be the best boilers on the market but CS is second to none.

I like and install Vokera boilers, have done for over 30 years, thier customer service is very good too but you either like Vokera or hate them, theyre a bit marmite to be completely honest.

Having said that my last three combis, since 1992, have all been Vokera's, I can't fault them, CS is good, warranties are honoured, thier technical phone help is easily up there with Worcester and Baxi and thier engineers know the boilers well.

Their boiler prices are excellent too the cheapest combi boiler is about £500 with five year warranty, thier flagship boiler is about a grand with ten year warranty and some of the stuff in the boilers is truly outstanding especially the Unica Max which can run a heat pump, however thier entry level boiler the Vibe Max has a modulation ratio of 10-3 which is pretty impressive plus the boiler has bluetooth, a timer App and it even has a manual switch for the heating which basically overrides the boiler control panel ie it's just like a light switch so click on for heating and click off to turn the heating off which is pure 1980s stuff but older customers really strugle with modern boiler technology, plus they're bringing out a smart controller and they employ OT technology across the range.

I have a Vokera Vision Plus, an outdoor sensor, OT and weather compensation and smart programmable room thermostat and being completely honest it's not worth the bother, I think Vokera's efficiency figures for thier boilers with the above is 97% without those things it's about 92% but the mean efficiency drops down to about 83% cause the boilers don't condense all of the time.

Tony

PS, Vokera do heat pumps too and solar hot water as do Worcester Bosch and most of the other boiler manufacturers.
 
Thanks guys. Thanks @twotone. Nobody commented on the possibility of combining a gas boiler with a heat pump in the future. Is that a thing?
Hi @gavreid I am not aware of such a thing and I cannot see any real advantages there would be (possibly use the heat pump to pre heat the water pipes going into the gas boiler?).

Heat pumps are the future, but they do have their own problems. Air source heat pumps generate the least heat when it is very cold outside which is when you need it the most. Ground source heat pumps are much more expensive to install but have access to energy from the earth and so are not limited on cold days (providing they have been specced to deliver the required energy when it is a very cold day). If you are luckily enough to have a river or a stream crossing your property then a water based heat pump becomes viable, but with all the infrastructure required can be as expensive as a ground source heat pump (basically same advantages / disadvantages).

Also all heat pumps are more effective at delivering lower temperature energy and so generally require large radiating surfaces (underfloor) and so often are not a straight swap for a gas central heating system.

As twotone has said, insulate, insulate and insulate to reduce your energy requirements in the first place. Makes your running costs less and any system you choose to heat your house with then be cheaper as there is less of a heat requirement.
 
Thanks guys. Thanks @twotone. Nobody commented on the possibility of combining a gas boiler with a heat pump in the future. Is that a thing?

I would have thought very unlikely to be a thing unless you have a very big property to heat. It's normally one or the other. Assuming you live in a normal house, my guess is that most plumbers will look at you funny if you start talking about having both.
 
Go with Worcester Bosch Gav, they might not be the best boilers on the market but CS is second to none.

Having looked at boilers in the not too distant past (cos I needed one), the WB 4000 system boilers can modulate down to as low as 2kw. That is really low. No chance of cycling. Will be very efficient.
 
Also all heat pumps are more effective at delivering lower temperature energy and so generally require large radiating surfaces (underfloor) and so often are not a straight swap for a gas central heating system.

Building regs require new gas boilers to operate at 55 deg flow now too I think - since June?
 
Having looked at boilers in the not too distant past (cos I needed one), the WB 4000 system boilers can modulate down to as low as 2kw. That is really low. No chance of cycling. Will be very efficient.

Personally I'd go for the WB 8000 Life @Ponty had one installed in his mum's house, think he really likes it.

Also I think WB have problems sourcing fans for the 4000 series boilers or they did have recently.
 
All these digital gizmos to heat the house and water. Okay, I'm sure they work but must add complexity to what has been a straightforward domestic energy installation for many decades. I know this s prob. just me, but we want to do what we've always done; turn the water on at a certain time and off again a couple of hours later (or by timer, depending on season). Re. heating, to turn it on manually when needed and have it go off automatically by timer or manually on v. cold days if needed before late afternoon.

I'm a believer in simplicity. I s'pose if you find it an advantage to operate your heating by phone whilst driving back, okay, but I kinda got used to the house taking time to heat up if away for days in cold weather. Anyway, I guess it's totally different for retired people compared to digitally savvy and technologically keen non retirees.

My sister has their house on permanent heating, activated by thermostat. My bro.-in-law thinks that is more efficient even though the house is generally occupied. Others think not, (incl. me) but I've not read anything to come down on one method or the other as the better option.
 
All these digital gizmos to heat the house and water. Okay, I'm sure they work but must add complexity to what has been a straightforward domestic energy installation for many decades. I know this s prob. just me, but we want to do what we've always done; turn the water on at a certain time and off again a couple of hours later (or by timer, depending on season). Re. heating, to turn it on manually when needed and have it go off automatically by timer or manually on v. cold days if needed before late afternoon.

I'm a believer in simplicity. I s'pose if you find it an advantage to operate your heating by phone whilst driving back, okay, but I kinda got used to the house taking time to heat up if away for days in cold weather. Anyway, I guess it's totally different for retired people compared to digitally savvy and technologically keen non retirees.

My sister has their house on permanent heating, activated by thermostat. My bro.-in-law thinks that is more efficient even though the house is generally occupied. Others think not, (incl. me) but I've not read anything to come down on one method or the other as the better option.

I wouldn't have been too bothered in the past but they say that 15% savings can be expected. If true, that's not to be sniffed at any longer.
 
Interesting and not something that I was aware of. But understandable in the desire to make systems more efficient.

I thought that the water needed to be above 57 Deg C to avoid Legionnaire's disease being able to grow in the system.

Yes, these new boilers can go full blast on the water to heat up a cylinder in about 30 mins then tick over on the heating, adjusting for the outside temp.
 
I wouldn't have been too bothered in the past but they say that 15% savings can be expected. If true, that's not to be sniffed at any longer.

Gav 15% savings is nothing, even with the cost of energy today, you might end up spending £10,000 or even more if you install a heat pump, that’s a lot of gas.


With my set up the cost of materials was about £1500 and I doubt very much my gas usage is down much cause the old boiler was a condensing combi and I had a non WIfi programmable room thermostat too but no weather comp, OT or an outside sensor.

And no labour cost either.

For anyone else ie non heating engineer/plumber you’re probably looking at about £3000 for Glasgow prices.
 
Yes, these new boilers can go full blast on the water to heat up a cylinder in about 30 mins then tick over on the heating, adjusting for the outside temp.

Probably even less than that time Gav pretty sure the recovery time on a dual coil unvented cylinder is about twenty minutes if the cylinder has been depleted and that’s unlikely.
 
All these digital gizmos to heat the house and water. Okay, I'm sure they work but must add complexity to what has been a straightforward domestic energy installation for many decades. I know this s prob. just me, but we want to do what we've always done; turn the water on at a certain time and off again a couple of hours later (or by timer, depending on season). Re. heating, to turn it on manually when needed and have it go off automatically by timer or manually on v. cold days if needed before late afternoon.

I'm a believer in simplicity. I s'pose if you find it an advantage to operate your heating by phone whilst driving back, okay, but I kinda got used to the house taking time to heat up if away for days in cold weather. Anyway, I guess it's totally different for retired people compared to digitally savvy and technologically keen non retirees.

My sister has their house on permanent heating, activated by thermostat. My bro.-in-law thinks that is more efficient even though the house is generally occupied. Others think not, (incl. me) but I've not read anything to come down on one method or the other as the better option.

Mike most of the ‘gizmos’ don’t affect efficiency they’re merely for comfort and that includes smart TRVs.

Normal TRVs are worse than useless but the efficiency savings using them are about 5% I have a TRV on about 15 rads and never use them cause they contribute to boiler cycling by increasing the return temperature to the boiler but try telling a customer that.
 


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