New boiler query

km1500

I am going to have my very old glowworm ultimate 70FF boiler replaced The heating system is the type with a hot water cylinder in the airing cupboard and a header tank in the attic 

could anyone recommend the best way to get quotes. I intend to go to a local installer and get one from boxt

is it worth going to the boiler manufacturers themselves which boiler manufacturer would anyone recommend?

it is a house with about 10 radiators and 2 towel rails

thank you

Nebbit

I think recommendation by a trusted tradesman is important, as so much of the value is the labour for the tradesman to install the boiler. We have a 5 bedroom house and recently bought a Worcester Bosch Greenstar - that company has good after sales service. If a tempted to buy a boiler from a firm you have never heard of, be careful. Remember that you will need the availability of spare parts going forward several years into the future. 

The_Green_Hornet

Which? have a boiler buying guide which you may find useful.

How to buy the best boiler - Which?

FreeBear

km1500 said:

I am going to have my very old glowworm ultimate 70FF boiler replaced The heating system is the type with a hot water cylinder in the airing cupboard and a header tank in the attic 

could anyone recommend the best way to get quotes. I intend to go to a local installer and get one from boxt

is it worth going to the boiler manufacturers themselves which boiler manufacturer would anyone recommend?

it is a house with about 10 radiators and 2 towel rails

thank you

Sounds like you have a system very similar to my old one. Open vented and gravity fed domestic hot water.

Changed mine to a Viessmann 050 combi last year and took the opportunity to replumb the system and fit larger radiators in most rooms. Did all the plumbing myself to save money and just paid a Gas Safe engineer to install the boiler. In all, probably spent around £3500.

If I were to do a replacement now, I would seriously consider a heat pump - Octopus quoted me £2700 (subject to survey) earlier in the year, and that included fitting larger radiators throughout. Any additional plumbing work beyond a small amount to connect the heat pump would cost extra..

I would urge you to at least consider a heat pump (correctly specified and set up, potentially cheaper to run). If you are wedded to the idea of a replacement gas boiler, two things to look at:

• Minimum heat output - A good number is under 4kWh.
• Length of warranty - 10 year is pretty standard. 7 years or less indicates a budget boiler.

Why minimum heat output - If you fit new & larger radiators, you can run the system at a low flow temperature (good for efficiency). Combined with a smart thermostat, the boiler will automatically reduce the heat output as room temperatures approach the set point. On really cold days, it is possible that the heat loss through the fabric of the building exceeds the minimum boiler output. In this situation, the boiler will quietly tick over without "short cycling".

Short cycling is bad for boiler efficiency and also increases wear & tear on internal components, so if you can avoid this situation, you save money and extend the life of the boiler.

If you decide to go for a combi boiler, it needs to be rated high enough to heat hot water based on the flow rate of your cold water supply. With a system boiler coupled to a tank like you already have, you only need a boiler large enough to heat the 10 radiators. A bigger boiler is OK if you want a fast reheat of the tank (and the tank is suitable). But few people will be wanting to run multiple baths per hour every day - Quite likely you only need a 14kW boiler and can live with a 30min reheat time of the tank. Anyone that suggests you need a 30kW (or more) boiler is an idiot.

My recommendation for boiler manufacturer would be either Viessmann (050 or 100) or Worcester Bosch (either the 4000 or 8000 series). Both come with 10/12 year warranty, and the Viessmann is OpenTherm compatible (gives you a wider range of smart thermostats to choose from).

km1500

Thanks all for taking the time to respond it is extremely helpful

if you were to put a house on the market with the heat pump instead of a gas boiler would the heat pump put buyers off or attract them do you think?

FreeBear

km1500 said: If you were to put a house on the market with the heat pump instead of a gas boiler would the heat pump put buyers off or attract them do you think?

A heat pump may put some buyers off at present. But as attitudes change, it could turn in to a selling point. If you can demonstrate low running costs, that would be another plus.

km1500

having done some research I have decided to go with either the Worcester Bosch greenstar 4000,  27i or 21RI or the Viessmann Vitodens 100-W heat only.

does anyone have any recommendations about which manufacturer to go with? 

thanks

badger09

km1500 said:

having done some research I have decided to go with either the Worcester Bosch greenstar 4000,  27i or 21RI or the Viessmann Vitodens 100-W heat only.

does anyone have any recommendations about which manufacturer to go with? 

thanks

I can’t comment on Viessmann as never had one. We had WB Greenstar GR8700iw installed in our 1970s built sprawling extended 4 bed bungalow in Sept 21 within a year of moving in. Installed by WB approved engineer so 12 year guarantee. 

Pressure kept dropping and after exhaustive tests, established leak/leaks in pipes buried somewhere in the concrete floor. Cue expensive & disruptive rerouting of pipes above ground. Despite this, we’re very happy with it and over time I’ve managed to drastically reduce gas consumption. 

We also had a WB installed in our previous home. 7 years of trouble free use before we moved. 

FreeBear

km1500 said:

having done some research I have decided to go with either the Worcester Bosch greenstar 4000,  27i or 21RI or the Viessmann Vitodens 100-W heat only.

does anyone have any recommendations about which manufacturer to go with?

Viessmann 100 - Minimum output of ~3kW, and OpenTherm compatible. Standard warranty is 10 year with an option to extend to 12 years.

Whilst the 21Ri is 9.64kW (net input), and the 27i is 7.5kW - Both the 21kW and 27kW are way bigger than you really need. Standard warranty is just 5 years, but can be extended to 10 subject to conditions.

The Greenstar 4000 will modulate down to 3.2kW, so on par with the Viessmann. But WB don't "do" OpenTherm, so you are restricted on choice of smart controls. Warranty is 7 year, but like the 21/27RI can be extended to 10.

Based on the above, your choice really boils down to the Greenstar 4000 or the Viessmann 100 - Personally, I'd go for the Viessmann (either the 16kW or 19kW) due to the OpenTherm compatibility. The Greenstar 4000 (18kW version) would only get a consideration if a 10 year warranty was included.

born_again

km1500 said:

I am going to have my very old glowworm ultimate 70FF boiler replaced The heating system is the type with a hot water cylinder in the airing cupboard and a header tank in the attic 

could anyone recommend the best way to get quotes. I intend to go to a local installer and get one from boxt

is it worth going to the boiler manufacturers themselves which boiler manufacturer would anyone recommend?

it is a house with about 10 radiators and 2 towel rails

thank you

Let local installer source & supply the boiler. may cost a bit more, but that leaves any issues in their ball court. Unlike when you buy the boiler & get someone to install it. Where they will blame each other.

Gerry1

born_again said:

km1500 said:

I am going to have my very old glowworm ultimate 70FF boiler replaced The heating system is the type with a hot water cylinder in the airing cupboard and a header tank in the attic 

could anyone recommend the best way to get quotes. I intend to go to a local installer and get one from boxt

is it worth going to the boiler manufacturers themselves which boiler manufacturer would anyone recommend?

it is a house with about 10 radiators and 2 towel rails

thank you

Let local installer source & supply the boiler. may cost a bit more, but that leaves any issues in their ball court. Unlike when you buy the boiler & get someone to install it. Where they will blame each other.

They may well do a better job because they have a reputation to defend in the local area, and they'll know you won't go back to them for servicing if you weren't happy.