New boiler time and haven't got a clue!

[mfkent]

Hi guys, complete plumbing novice here after a bit of advice please
I need a new boiler fitting as out prehistoric kingfisher is finally on its last legs!
But have not got a clue what to replace it with.
Currently the system has a tank in a cupboard halfway up the stairs with a heating element in (that is hardly ever used). There is a rad in the bathroom that gets hot when the hot water is on (a summer circuit apparently).
I'd like to keep the system as it is cos I like the way it works so would I just need a normal boiler (not combi) for this?


Sorry to be asking what is most probably a simple stupid question but I aint got a clue!

I've done the calculator thing (estimated (over I think) my house size) and it reckons 18kw. I will be getting some quotes for a replacement, so my next questions is what is a good, reliable boiler? Is it cheaper to source a boiler yourself or do plumbing engineers get better prices, or do they put a huge mark-up on?

Thanks in advance,

Martin

 

[D_Hailsham]

Currently the system has a tank in a cupboard halfway up the stairs with a heating element in (that is hardly ever used). There is a rad in the bathroom that gets hot when the hot water is on (a summer circuit apparently).
I'd like to keep the system as it is cos I like the way it works so would I just need a normal boiler (not combi) for this?

The heating element in the cylinder is just for emergencies, if the boiler fails. You would only need a "regular", i.e heat only boiler.

I've done the calculator thing (estimated (over I think) my house size) and it reckons 18kw.

Which calculator did you use?
How does that compare with the output of your Kingfisher?

I will be getting some quotes for a replacement, so my next questions is what is a good, reliable boiler? Is it cheaper to source a boiler yourself or do plumbing engineers get better prices, or do they put a huge mark-up on?

If you source the boiler yourself, you have to accept that it will be your responsibility to contact the seller or manufacturer if the boiler develops a fault. If you ask the installer to buy it, he accepts full responsibility.

You may be able to buy a boiler at less than list price, but the installer will probably be able to get it at an even lower price. Of course they will put on a mark up, it's to cover any call outs while the system is under warranty, but you shouldn't have to pay more than the list price for the boiler and probably no more than you can get it yourself.

Many installers just give an overall price for the job; they do not like breaking it down into labour and materials.

As for which make to buy, you will get as many replies as there are boiler manufacturers. Each installer has his favourites and dislikes.

Some manufacturers offer 5 or 10 year warranties on their boilers, provided they are installed by an approved engineer. So it's worth checking with the manufacturer before signing the contract.

These warranties, however, normally insist that you have the boiler serviced annually; so get this built into the contract with the installer and pay for it up-front. It will be cheaper in the long run.

 

[RigidRaider]

Best advice I can give you is to invite three well-established family plumbing cos along to give their recommendation and a quote. Don't go for the cheapest; go for the one who seems most "with it" and prepared to make an effort to get it right for you.

 

[mfkent]

Currently the system has a tank in a cupboard halfway up the stairs with a heating element in (that is hardly ever used). There is a rad in the bathroom that gets hot when the hot water is on (a summer circuit apparently).
I'd like to keep the system as it is cos I like the way it works so would I just need a normal boiler (not combi) for this?

The heating element in the cylinder is just for emergencies, if the boiler fails. You would only need a "regular", i.e heat only boiler.

Thanks

I've done the calculator thing (estimated (over I think) my house size) and it reckons 18kw.

Which calculator did you use?
How does that compare with the output of your Kingfisher?

I used the calculator at http://www.sedbuk.com/
Not sure about the output of the Kingfisher, I'll check when I get home.

I will be getting some quotes for a replacement, so my next questions is what is a good, reliable boiler? Is it cheaper to source a boiler yourself or do plumbing engineers get better prices, or do they put a huge mark-up on?

If you source the boiler yourself, you have to accept that it will be your responsibility to contact the seller or manufacturer if the boiler develops a fault. If you ask the installer to buy it, he accepts full responsibility.

You may be able to buy a boiler at less than list price, but the installer will probably be able to get it at an even lower price. Of course they will put on a mark up, it's to cover any call outs while the system is under warranty, but you shouldn't have to pay more than the list price for the boiler and probably no more than you can get it yourself.

Many installers just give an overall price for the job; they do not like breaking it down into labour and materials.

As for which make to buy, you will get as many replies as there are boiler manufacturers. Each installer has his favourites and dislikes.

Some manufacturers offer 5 or 10 year warranties on their boilers, provided they are installed by an approved engineer. So it's worth checking with the manufacturer before signing the contract.

These warranties, however, normally insist that you have the boiler serviced annually; so get this built into the contract with the installer and pay for it up-front. It will be cheaper in the long run.

Sounds fair, time to get the phonebook out and get some quotes

Thanks for the advice.

 

[D_Hailsham]

I used the calculator at http://www.sedbuk.com/
Not sure about the output of the Kingfisher, I'll check when I get home.

That's a reliable calculator. If you can't find the info about the Kingfisher, just post the exact model number or the Gas Council (GC) number and we can look it up.

You have not said anything about radiators. If they are as old as the boiler they may be suspect; it all depends on how well the system has been maintained, i.e inhibitor in the system regularly replaced or topped up.

Does your house get warm enough for you in the depths of winter? If so the rads are probably the right size, but their output may drop slightly when you fit a condensing boiler.

If you want to check the rads, you can use the Stelrad Elite Catalogue to find out their output.

 

[mfkent]

I used the calculator at http://www.sedbuk.com/
Not sure about the output of the Kingfisher, I'll check when I get home.

That's a reliable calculator. If you can't find the info about the Kingfisher, just post the exact model number or the Gas Council (GC) number and we can look it up.

You have not said anything about radiators. If they are as old as the boiler they may be suspect; it all depends on how well the system has been maintained, i.e inhibitor in the system regularly replaced or topped up.

Does your house get warm enough for you in the depths of winter? If so the rads are probably the right size, but their output may drop slightly when you fit a condensing boiler.

If you want to check the rads, you can use the Stelrad Elite Catalogue to find out their output.

The rads are all pretty crap to be fair, so they are all gonna get changed at the same time. The house gets very toasty warm so I have got to assume that they are all the right size

 

[doitall]

If you have TRV's fitted then big is best, as it cover severe weather.

 

[D_Hailsham]

If you have TRV's fitted then big is best, as it cover severe weather.

If the OP does not have them, he will have to fit TRVs, cylinder stat, room stat and possibly a motorized valve or two.

The Kingfisher is rather old, so the system may have gravity HW. Mine did but, as the boiler had only been installed six months before we moved into the house, I converted it to C Plan; and it stayed like that until we moved 13 years later.

Big rads also allow the boiler to run at lower temperatures, so more chance of running in condensing mode. But there must be a limit to how much you can oversize.

 

[Agile]

If the cylinder ( tank ) is not foam covered then it should be replaced too.

If its yellow foam covered then it can be kept but would reheat faster if replaced.

If its green or blue then it is not necessary to replace it.

18 kW seems a little high and I assume that includes the 2 kW for water heating.

Can you briefly describe house, age, number of beds and wall construction?

16 kW for the house would usually indicate a four bed detached with uninsulated cavity walls. Insulating the cavity gives a great benefit in lowering heat losses and thus fuel costs.

18 kW is the nominal size of many heat only or system boilers.

Tony

 

[doitall]

The point is most boilers, The Avanta 18v for example modulates down to 6KW, so would be perfectly in range for what the OP wants.

 

[D_Hailsham]

The point is most boilers, The Avanta 18v for example modulates down to 6KW, so would be perfectly in range for what the OP wants.

That may be true for heat only boilers, but it's a different story for many combis. The lowest a WB combi modulates to is 7.2kW and some only go down to 9.4kW. The same is true of Vaillant's. Their System and OV boilers will go down to 5kW but most combis only go down to 10-12kW; unless it's the 824, which goes down to 6.7kW. But that only produces 24kW for hot water.

The Avanta are exceptions, they all go down to 6kW, even the 39kW combi. Just a pity that the smaller boilers, such as the 12 and 15kW heat only versions, don't go lower than 6kW.

 

[Agile]

Thats a very important point !

I have seen so many 24 kW or higher power combis being fitted in a small property and give serious problems on heating.

One was a 28 kW combi in a one room studio flat !

However the fact a boiler can modulate down is no excuse for fitting an over sized boiler.

I saw a Keston last night which was a 55 kW in a four bed house. Of course only half of the 55 kW would have got out of the boiler through the 22 mm heating feed pipe! More would have been lost in the isolating valve used as an auto by-pass!

Tony

 

[mfkent]

Thanks for all the replies.

So, the prehistoric boiler in the house currently is a Kingfisher RS80.
The tank was replaced about 4 years ago and is green foam lagged, but is getting a bit furry round all the joints.
The rads do not have TRVs.
The house is a 3/4 bed detached. Built in the 50's, cavity walls are insulated, dunno what with, it was done before we moved in. UPVC windows all round.
Upstairs it has 3 bedrooms and one bathroom.
Downstairs it has a single story extension which extended the kitchen and provided the 3rd room which is now part of a through lounge/diner. the front room is the 4th bedroom / study /junk room!
The boiler heats the water and rads perfectly well but we want to change the system for something a little more efficient
Oh and yes it's gravity HW.

 

[htgeng]

I'm fitting a couple of the Atag open vent boilers next month. These modulate from 17.7kw down to 4.4kw.

I normally convert to sealed so this is a new thing for me. One of them is a floor standing beast(ideal?) with a C plan setup. This is one that Im thinking of fitting a dunsley too as they've mentioned they want a wood stove at some point.

The other one is a Netaheat. Again I would have normally changed to sealed, but all the pump/valves look fine so the Atag O/V seems a better solution to replace the naughty Potty!

Is anyone else looking at fitting these models? Open a thread in the CC if you want to discuss it.

 

[D_Hailsham]

The house is a 3/4 bed detached. Built in the 50's, cavity walls are insulated, dunno what with, it was done before we moved in. UPVC windows all round.
Upstairs it has 3 bedrooms and one bathroom.
Downstairs it has a single story extension which extended the kitchen and provided the 3rd room which is now part of a through lounge/diner. the front room is the 4th bedroom / study /junk room!

18kW does sound a bit high for a house that size.

Try using the Energy Saving Trust Calculator.

You will have to divide the house up into the original and the extension, and treat each part separately.