which boiler option? choice of 5

[Glasgowrob]

multiple quotes in for new boilers for the house. 3 bed semi with 10 radiators and 1bathroom with our shower ran directly from the boiler.

Currently running a rather old voikera combi which is somewhat past its best

all quotes are for full removal and install of the new boiler, linking it up to our existing hive system and a new flue extension

1. Isolate, drain, Disconnect and remove the current combi boiler.
2. Reconfigure the current pipework to suit the new layout.
3. Mount and attach the new boiler to the wall via a support bracket in the same location.
4. Connect all relevant pipework to combi including waste pipework for condense.
5. Installation of a magnetic filter (Adey Micro 2)
6. Install the new flue system exceeding the exterior ROOF. (Seal with intumescent silicone)
7. 240v supply to be connected via existing HIVE
8. Fill the heating system and remove excess air.
9. Test the gas line to confirm safety.
10. Complete commissioning paperwork.
11. Register the warranty with the manufacturer.
12. Full chemical flush of current system to remove any debris from the system (X800 system cleaner)
13. Balance current radiators to achieve even flow around the system.
14. Complete handover and instructions on how to use the new product and programmer.



VIESSMANN VITODENS 050 30KW HE COMBI (A rated product) 10 year warranty £2840
GLOW WORM ENERGY 30KW HE COMBI (A rated product) 7 year warranty £2610
ALPHA E-TEC 30KW HE COMBI (A rated product) 10 year warranty £2730
WORCESTER 4000 30KW HE COMBI (A rated product) 10 year warranty £3130
WORCESTER 1000 30KW HE COMBI (A rated product) 5 year warranty £2530



i know nothing about boilers so can anyone offer some insight as to what i should be considering out of the 5 above and any reason other than warranty that some are better buys than others?

[Danm1les]

We had a Viessman boiler at our last house and it was installed a few years before we moved in. It was faultless the time that were there and the only comment our plumber made was that is was a very good boiler, not as popular was Worcester or Vailant in the UK.

Current house was a Worcester compact boiler, that has been a pain as to get to any of the innards, the boiler has had to come off the wall.

[Griff_4988]

Go for either a Worcester or a Vailent. Both are Which? Magazine best buys.

[budgie smuggler]

Nobody ever mentions Alpha, I've had one of the previous series, Intec, and found it decent. Had an issue and it was sorted under warranty with no trouble.

[Simon_GH]

Griff_4988 said:

Go for either a Worcester or a Vailent. Both are Which? Magazine best buys.

This would be my approach. Plus, around half the price is fitting so it’s cheaper to spend more on a decent boiler that lasts longer because any savings will be instantly wiped out if you have to replace an inferior boiler earlier.

Edited to say I appreciate more expensive doesn’t necessarily equal better but in this case it probably does.

[OutInTheShed]

OP mentions Hive?

A boiler is a boiler is a boiler, until it goes wrong.
You will find fans of several makes, opinions about reliability.
A long warranty is good!
The controls however have big influence on how well it heats your house.

Is there any difference in how these boilers will integrate with the Hive stuff?
My boiler is getting on a bit now, but one of its main good points is the 'load compensation' working very well, it controls the flow temperature to suit how far below target the room stat is. I'd be interested in how the boiler will do that with the HIve or what other control strategy such as weather Compensation would be used. When first installed, my boiler was running weather compensation, it was a hopeless shambles. 'Approved installer' had no clue. Some of the boiler co's engineers weren't much better, firmware was changed in the boiler.

Time has moved on.
These days I'd be looking at integrating some smart TRVs
I'd certainly want it easier to re-program or tweak the program.

Another thought is to check the cost of annual services to keep the warranty.

[Glasgowrob]

done dusted went with the worcester 4000

install booked for tommorow

[dhutch]

Danm1les said:

We had a Viessman boiler at our last house and it was installed a few years before we moved in. It was faultless the time that were there and the only comment our plumber made was that is was a very good boiler, not as popular was Worcester or Vailant in the UK.

Our millage is the same, got a Vitodens 100 system boiler which went in to the house with the previous owners in 2012 and its been fine with us for the last 7 years.

Little hiccup this winter, which was a combination of a load of crap in the system (old house, previous owners ran it without magaclean etc) and a failed hot water cylinder interface box.

Bit of faff diagnosing the latter, but in terms of the boiler, a flush, two new hoses, and prv and a air valve replaced basically all the rubber parts and will hopefully see it on its way for a good while yet.

The difference between a 7 and 10 year warranty on something that should last 20 years is a bit of a moot point, but its not great that the Worcs 100 only comes with 5years cover!

[Saleen836]

Glasgowrob said:

done dusted went with the worcester 4000

install booked for tommorow

Is the prices quoted after each boiler the total install cost for parts & labour or just the cost of the boiler?

[MercmanSL]

OutInTheShed said:

OP mentions Hive?

A boiler is a boiler is a boiler, until it goes wrong.
You will find fans of several makes, opinions about reliability.
A long warranty is good!
The controls however have big influence on how well it heats your house.

Is there any difference in how these boilers will integrate with the Hive stuff?
My boiler is getting on a bit now, but one of its main good points is the 'load compensation' working very well, it controls the flow temperature to suit how far below target the room stat is. I'd be interested in how the boiler will do that with the HIve or what other control strategy such as weather Compensation would be used. When first installed, my boiler was running weather compensation, it was a hopeless shambles. 'Approved installer' had no clue. Some of the boiler co's engineers weren't much better, firmware was changed in the boiler.

Time has moved on.
These days I'd be looking at integrating some smart TRVs
I'd certainly want it easier to re-program or tweak the program.

Another thought is to check the cost of annual services to keep the warranty.

It’s not really true that a boiler is a boiler. Not all boilers support Opentherm, and/or weather compensation. Some boilers modulate down better than others and have better controls and user interfaces.

Personally I wouldn’t use smart TRV’s at all, despite what the manufacturers claim they don’t always save energy or improve comfort.

[39sl]

MercmanSL said:

It’s not really true that a boiler is a boiler. Not all boilers support Opentherm, and/or weather compensation. Some boilers modulate down better than others and have better controls and user interfaces.

Personally I wouldn’t use smart TRV’s at all, despite what the manufacturers claim they don’t always save energy or improve comfort.

And as is in life, an alternative viewpoint has shown me that my use of gas heating proves that Evohome saves me money every year, but the level of savings depends on how many people live in your house, and perhaps how big a house it is. More bedrooms than people means the benefits of leaving some rooms unheated when unused starts to drive savings in gas usage.
I had a WB 42CDI installed 12 years ago and I bought it based on the hot water performance. Fast forward and I’ve realised that a Veissman Vitodens 100-W is more suited to me due to the modulation range of 10:1 and full opentherm support means the Evohome will better integrate with the boiler and provide an effective and more efficient usage profile.
This is all academic as you’ve made the decision, and I’m sure it will serve you well.

[Joseph Ducreux]

I have a Worcester Bosch 8700 Style something or other, big monolith looking thing.

Best thing I did was ditch the Nest for Bosch Easycontrol: https://www.worcester-bosch.co.uk/products/boiler-...

As it's the kit designed for the boiler, it seems to handle modulating the boiler automatically, running it more efficiently and coupled with the smart TRVs have seen gas usage drop through the floor.

The nest kit just turned the boiler on at 100% power or turned it off, that was it - I guess anything else that isn't opentherm will do the same thing. The 8700 isn't OT-compatible without an adaptor as it uses its own comms protocol which the Easycontrol speaks, not sure if that's the same for the newer boilers or not however.

Edited by Joseph Ducreux on Tuesday 6th May 23:34

[megaphone]

They are going to power flush the system, yes? Just running a chemical around is not good enough.

[MercmanSL]

39sl said:

And as is in life, an alternative viewpoint has shown me that my use of gas heating proves that Evohome saves me money every year, but the level of savings depends on how many people live in your house, and perhaps how big a house it is. More bedrooms than people means the benefits of leaving some rooms unheated when unused starts to drive savings in gas usage.
I had a WB 42CDI installed 12 years ago and I bought it based on the hot water performance. Fast forward and I’ve realised that a Veissman Vitodens 100-W is more suited to me due to the modulation range of 10:1 and full opentherm support means the Evohome will better integrate with the boiler and provide an effective and more efficient usage profile.
This is all academic as you’ve made the decision, and I’m sure it will serve you well.

I went from the standard on/off programmer and bi-metalic room thermostat to a Drayton Wiser "smart" system with multiple smart TRV's and room thermostats. At the same time I changed from a simple on/off schedule to multiple schedules with setback temperatures rather than just being off. I definately saved energy and hence cost but after running the system for a couple of winters I started to be frustrated with individual smart TRV's firing the boiler to heat just one or two rooms, with a gas boiler this is very inefficient. Also my 10 year old boiler would only modulate down to 7.2kw! this resulted in short cycling which cost energy so I gradually removed smart TRV's in order to stop heating at a room level and start heating the house with multiple rooms heating at the same time. I am now using just a single Wiser room thermostat setup with setback temps and manual TRV's on all radiators acting as temperature limiters, this has resulted in the boiler running much more efficiently and has saved a little be more in energy whilst increasing comfort.

What I have experienced is that a smart heating system can save energy but not in every situation and not enough to warrant the cost of multiple smart TRV's.

[119]

Viessman for us.

Had too many bad experiences with WB, even to the point that our current house had a three year old one installed and the first thing I did was to bin it off.

[Sheepshanks]

Joseph Ducreux said:

I have a Worcester Bosch 8700 Style something or other, big monolith looking thing.

Best thing I did was ditch the Nest for Bosch Easycontrol: https://www.worcester-bosch.co.uk/products/boiler-...

As it's the kit designed for the boiler, it seems to handle modulating the boiler automatically, running it more efficiently and coupled with the smart TRVs have seen gas usage drop through the floor.

The nest kit just turned the boiler on at 100% power or turned it off, that was it - I guess anything else that isn't opentherm will do the same thing. The 8700 isn't OT-compatible without an adaptor as it uses its own comms protocol which the Easycontrol speaks, not sure if that's the same for the newer boilers or not however.

Hmmm - even with relay on/off control the boiler will modulate itself down quickly, if it ran at 100% it would be mental - the CH pipework probably can't handle that for more than a few moments. Quick Google suggests it'll go down to 10%, which is pretty good.

We do have a bit of an issue with the 30kW Glow Worn boiler and Tado TRV control as that boiler only goes down to 25% and that's often too much.

[Joseph Ducreux]

Sheepshanks said:

Joseph Ducreux said:

I have a Worcester Bosch 8700 Style something or other, big monolith looking thing.

Best thing I did was ditch the Nest for Bosch Easycontrol: https://www.worcester-bosch.co.uk/products/boiler-...

As it's the kit designed for the boiler, it seems to handle modulating the boiler automatically, running it more efficiently and coupled with the smart TRVs have seen gas usage drop through the floor.

The nest kit just turned the boiler on at 100% power or turned it off, that was it - I guess anything else that isn't opentherm will do the same thing. The 8700 isn't OT-compatible without an adaptor as it uses its own comms protocol which the Easycontrol speaks, not sure if that's the same for the newer boilers or not however.

Hmmm - even with relay on/off control the boiler will modulate itself down quickly, if it ran at 100% it would be mental - the CH pipework probably can't handle that for more than a few moments. Quick Google suggests it'll go down to 10%, which is pretty good.

We do have a bit of an issue with the 30kW Glow Worn boiler and Tado TRV control as that boiler only goes down to 25% and that's often too much.

Maybe 100% on/off was a bit of an overestimation, but the metric of gas usage has dropped massively since switching from nest to Easycontrol.

It now tends to run the burner at a lower level then shut off the burner but keep the pump running circulating the water round the system, rather than shutting off the burner and the pump at the same time when the nest ceased calling for heat.

Ultimately, my point was that the nest is pretty much an on/off switch in a fancy housing that you can control via the app, the Easycontrol integrates with the whole system much as I assume an OT system would do.

[Sheepshanks]

Joseph Ducreux said:

Maybe 100% on/off was a bit of an overestimation, but the metric of gas usage has dropped massively since switching from nest to Easycontrol.

It now tends to run the burner at a lower level then shut off the burner but keep the pump running circulating the water round the system, rather than shutting off the burner and the pump at the same time when the nest ceased calling for heat.

Ultimately, my point was that the nest is pretty much an on/off switch in a fancy housing that you can control via the app, the Easycontrol integrates with the whole system much as I assume an OT system would do.

One of our daughter's has the Bosch controller (her's is called Worcester Wave) and I got the impression is was primarily desighned for underfloor heating - in any optimised mode it wasn't warming the house up quickly in the morning and in one mode it ran the pump 24/7. I think all she uses it for is remote on/off.

The great modulation ratio of your boiler is probably the big thing - it'll sit there for hours chugging away whereas outside of very cold weather ours is on and off often, and it has a long anti-cycle time (I could shorten the time but it's not a big issue and it would just cycle more).

[OutInTheShed]

MercmanSL said:

It’s not really true that a boiler is a boiler. Not all boilers support Opentherm, and/or weather compensation. Some boilers modulate down better than others and have better controls and user interfaces.

Personally I wouldn’t use smart TRV’s at all, despite what the manufacturers claim they don’t always save energy or improve comfort.

I was making a point, (quite badly in retrospect), that the controls are as important as the boiler.

Smart TRVs are like a lot of other gadgets, where they do the job you want they are good, but not a panacea for all circumstances.

[OutInTheShed]

Sheepshanks said:

Hmmm - even with relay on/off control the boiler will modulate itself down quickly, if it ran at 100% it would be mental - the CH pipework probably can't handle that for more than a few moments. Quick Google suggests it'll go down to 10%, which is pretty good.

We do have a bit of an issue with the 30kW Glow Worn boiler and Tado TRV control as that boiler only goes down to 25% and that's often too much.

For us, we find the gain is the boiler/controller ramping down the flow temp as the room approaches the desired temperature.
Being a combi, I think it also plays with the pump speed.
This works well in our house, the room temperature doesn't over shoot but gets up to set point quite quickly.
That saves gas for us, because we can leave the heating off until we know we need it.
Running the lowest plausible flow temp most of the time also increases efficiency a little.

With on/off control, the boiler will modulate to hit whatever flow temp is set.
You can fiddle with the flow temp manually to suit this month's weather or whatever.