Boiler dodgy dealers?

FlaatusGoat

My boilers on it's way out, 17 years young. Sad but true.

I've got a good idea on the replacement, a Worcester Greenstar 4000 24kw. Looking on 'the bay' I'm seeing sellers with literally a picture of the box, and a phone number on the photo. These are about £200 cheaper than the plumbers merchants, or more.

Do I sense a whiff of warranty voiding dodgeyness on these listings? Not sure if I should take a risk paying over a tonne with no come back.

Brie

I pay for these sort of things to be installed by someone recommended by someone who knows how good the tradesperson is.  A boiler has to be installed by someone who is accredited.  Not someone how simply knows how to hoist the machinery on to a wall and hood up a few pipes.  I'm happy to pay a tiny bit more to ensure it's done right.  

FlaatusGoat

Brie said:

I pay for these sort of things to be installed by someone recommended by someone who knows how good the tradesperson is.  A boiler has to be installed by someone who is accredited.  Not someone how simply knows how to hoist the machinery on to a wall and hood up a few pipes.  I'm happy to pay a tiny bit more to ensure it's done right.  

Who said anything about installation? Not quite sure what you've presumed?

Brie

Well if you're buying a boiler someone's going to have to put it in.  I've always done it all through a trusted tradesperson, purchase and installation.  Obviously some don't.  Would the person you want to install it be willing to do the work on something bought from "the bay"??  You might be buying something not quite as labelled and run into problems perhaps. 

Hence my assumption that one might buy a boiler from someone accredited who then also installs it.  Sorry if I missed the point.   What if you buy something, installer shows up and says no because that's not a proper Worcester and charges you £120 for call out for no work being done?

FlaatusGoat

Brie said:

Well if you're buying a boiler someone's going to have to put it in.  I've always done it all through a trusted tradesperson, purchase and installation.  Obviously some don't.  Would the person you want to install it be willing to do the work on something bought from "the bay"??  You might be buying something not quite as labelled and run into problems perhaps. 

Hence my assumption that one might buy a boiler from someone accredited who then also installs it.  Sorry if I missed the point.  

I'm the sort that will try and skimp and save and do as much stuff myself. But I wouldn't go near a boiler! My life is worth more than a few quid. So yes, to answer your question I have a heating engineer however the price they gave (unit only) was higher than what I saw on the bay. Just find it odd that these boilers are so reduced which makes me speculate as to why. 

FreeBear

Get a quote from someone like Boxt - You'll get a 10, or even 12 year warranty on most of their boilers.

But if this is a system or heat only boiler, do you really need 24kW ?

Most boilers are grossly over rated, and many do not modulate down low enough for a typical property. When I was looking for a combi boiler last year, the two things I looked at was a) Ability to heat DHW based on the flow I have, and b) Minimum heat output for heating. Although I have ~10kW of radiators, for much of the time, I only need 4-5kW to keep the house warm. In the end, I went for one that could modulate down to 3.2kW. Coupled with a smart(er) control system, it seems to spend much of its time running at ~4-5kW with a peak of 7-8kW at start up. If the minimum output was any higher, the boiler would be short cycling which is bad for efficiency and wasteful of gas.

Looking at the specs for the Greenstar 4000 24kW system boiler, it will modulate down to 3.2kW, so pretty good. Unless you have a pressing need for fast reheat of the hot water tank, the 12kW or 15kW would work just as well (with the added bonus of modulating down to 2kW). Marginally cheaper too, but only by a £100 or so. But you may find a package deal for the 24kW works out a few pounds cheaper.

silvercar

If you buy from a dodgy dealer advertising on EBay and the boiler proves to be faulty, you will have to pay for the new one to be reinstalled, if you buy through someone reputable on a ‘supply& fit’ basis, the costs of reinstalling won’t be down to you.

FlaatusGoat

FreeBear said:

Get a quote from someone like Boxt - You'll get a 10, or even 12 year warranty on most of their boilers.

But if this is a system or heat only boiler, do you really need 24kW ?

Most boilers are grossly over rated, and many do not modulate down low enough for a typical property. When I was looking for a combi boiler last year, the two things I looked at was a) Ability to heat DHW based on the flow I have, and b) Minimum heat output for heating. Although I have ~10kW of radiators, for much of the time, I only need 4-5kW to keep the house warm. In the end, I went for one that could modulate down to 3.2kW. Coupled with a smart(er) control system, it seems to spend much of its time running at ~4-5kW with a peak of 7-8kW at start up. If the minimum output was any higher, the boiler would be short cycling which is bad for efficiency and wasteful of gas.

Looking at the specs for the Greenstar 4000 24kW system boiler, it will modulate down to 3.2kW, so pretty good. Unless you have a pressing need for fast reheat of the hot water tank, the 12kW or 15kW would work just as well (with the added bonus of modulating down to 2kW). Marginally cheaper too, but only by a £100 or so. But you may find a package deal for the 24kW works out a few pounds cheaper.

You've taken the bull by the horns on my situation. Mainly living alone, very small 2 bed. Very good insulation and even in the depths of winter I'm scarcely running two radiators. So, as you've rightly pointed out being able to module down is a huge win. I think the less than 24kw options are heat or water only. Whereas I don't have a water tank and space is a premium so Combi is the way to go.

By the way, did you know it seems that the Greenstar 2000 like the 4000 has the ability to module down low? Good few hundred cheaper, too.

Still, money is tight. I may try and squeeze a couple more months out of my present boiler. Sometimes I can get a hot decent shower out of it, still...

FreeBear

FlaatusGoat said:

FreeBear said:

Get a quote from someone like Boxt - You'll get a 10, or even 12 year warranty on most of their boilers.

But if this is a system or heat only boiler, do you really need 24kW ?

Most boilers are grossly over rated, and many do not modulate down low enough for a typical property. When I was looking for a combi boiler last year, the two things I looked at was a) Ability to heat DHW based on the flow I have, and b) Minimum heat output for heating. Although I have ~10kW of radiators, for much of the time, I only need 4-5kW to keep the house warm. In the end, I went for one that could modulate down to 3.2kW. Coupled with a smart(er) control system, it seems to spend much of its time running at ~4-5kW with a peak of 7-8kW at start up. If the minimum output was any higher, the boiler would be short cycling which is bad for efficiency and wasteful of gas.

Looking at the specs for the Greenstar 4000 24kW system boiler, it will modulate down to 3.2kW, so pretty good. Unless you have a pressing need for fast reheat of the hot water tank, the 12kW or 15kW would work just as well (with the added bonus of modulating down to 2kW). Marginally cheaper too, but only by a £100 or so. But you may find a package deal for the 24kW works out a few pounds cheaper.

You've taken the bull by the horns on my situation. Mainly living alone, very small 2 bed. Very good insulation and even in the depths of winter I'm scarcely running two radiators. So, as you've rightly pointed out being able to module down is a huge win. I think the less than 24kw options are heat or water only. Whereas I don't have a water tank and space is a premium so Combi is the way to go.

By the way, did you know it seems that the Greenstar 2000 like the 4000 has the ability to module down low? Good few hundred cheaper, too.

Still, money is tight. I may try and squeeze a couple more months out of my present boiler. Sometimes I can get a hot decent shower out of it, still...

For a combi boiler, you need to know what your cold water flow rate is - Turn a tap on in the bath and time how long it takes to fill a 5l or 10l container. From that, you can calculate how many litres per minute you're getting. A mixer tap in the kitchen will have restrictions (tiny 8mm pipes and aeration devices) that limit the flow.

The Greenstar 2000 25kW combi will modulate from 3.4kW up to 25kW with a flow/return temp of 40/30 & 50/30°C. At 80/60°C, output is 3-24kW, but efficiency will be way down. DHW is rated at 9-10l per minute depending on temperature rise (40°C and 35°C respectively). In all, quite a reasonable set of numbers. The Greenstar 4000 is very similar in performance and just edges ahead in minimum output at 3kW to 3.3kW depending on flow/return temperature.

If you want to take advantage of low flow temperatures (and I would strongly recommend you do), run the room sizes through a heat loss calculator. Use a Delta-T of 40°C or lower. If you have thoughts of installing a heat pump in the future, a Delta-T of 20°C or even 10°C would be more suitable. But going that low will cause problems if you have micro-bore pipework.

Why run at low flow temperatures - Simples. The return temperature will be lower which pushes the boiler further in to condensing mode. This translate in to better efficiency (potentially 96-98%) and lower running costs.

On the subject of heat pumps, have you considered one ?

Octopus quoted me earlier in the year, and the price they gave wasn't much more than the gas boiler.