Boiler confusion

[ziggysoft]

Greetz All

My problem is I need to replace my 15 year old combi boiler with a new high efficiency one ASAP and add a few requirements....
Can a combi boiler heat my indirect cylinder to give me stored hot water?
What is the most reliable boiler to choose (my Ferrolli has been trouble free since installation) ?
I need this boiler to feed 15 large radiators ?

Any help greatly appreciated.

Many thanks
Ziggy

 

[plumber (new blood)]

no a combi can not do that,only a system boiler will. if you only have say 3 or 4 hot water draw-off point. remove the copper cylinder and weigh it in for scrap, then have a combi installed.if you have a few hot draw-offs go for say a 30kw model

 

[ChrisR]

Certainly a combi can do that! Just needs controls much like any other boiler. Can be good to eg take the kitchen potable HW off the combi and the bathroom off a cylinder, which you can pump or have at mains pressure.
All depends on your requirements and your mains supply pressure and flow.

 

[plumber (new blood)]

why not just let the combi do the lot,ant seem many combi`s ganged into hot water cylinders ???!! sould like crazy plumbing to me

 

[ziggysoft]

Thanks to everyone for replies but I must clarify things slightly.
I have recently installed a Solar panel on my roof which indirectly feeds to my 210 litre cylinder.
Lots of hot water for free.
There is a spare indirect connection on the cylinder which I want to connect to a replacement boiler.
I will definately NOT be getting rid of the cylinder I just want to be able to heat the water when available solar is not enough.
At the moment my large 3 storey house uses the stored hot water for 2 bathrooms and a shower.
My existing combi boiler supplies hot water to my kitchen and washroom and my central heating system.
I do not wish to put all my eggs in one basket by having all my hot water from one source plus the mains water supply in my area is sometimes erratic and because I have a large tank in the loft we can still have a shower/flush toilet etc.
All I want to know is if it is possible to indirectly heat water using a modern condensing boiler ?

Ziggy

 

[plumber (new blood)]

system boiler, combi will only work if you have an thermal heat store connected to the solar colector, like a water to water heat exchanger. No a system boiler is the only way to do this job mate. you have to be corgi to work with gas, and clear ski registered to install solar systems,also...yes an theres more, Part `p` registered to mess around with the electrics, and also be qulified for par `L` of the building regs to self cert the installation for energy efficiency, ha and people this use heating engineers have an easy time.

has you solar sysem got an expantion vessel are is it using a drain back system?

 

[DP]

Ziggysoft, Go with what Chris is stating. I have a combi boiler serving three zones- HW, sleeping area and living area zones. You CAN CERTAINLY use your existing and any other standard, system or a combi boiler to do this.

I would suggest you start with cleaning your existing system with chemicals and upgrade to a Y plan or S plan in preparation for replacement boiler. You might find a combi is cheaper option.

System treatment is a must for trouble free operation.

New blood has a lot to learn. Combi, even a bigger one, has it's limitations. Is it any wonder some people do NOT WANT a combi. I like them because all I do is repair them and not fit them.

An older boiler, if it is trouble free, is better kept than going for a steamer that will cost you arm and a leg for repairs

 

[plumber (new blood)]

why go for a combi when you don`t need one?, if the guy has a solar cylinder why not use this to supply all the hot water and plumb the system in as an `S` PLAN, `Y` is pointless as you would have to use a 2 port zone valve as well as a 3 way valve, for the cylinder positive energy cut-off that is if the cylinder is unvented

leave it to the pro`s if your not sure what your doing.

(new blood) don`nt be fooled by the name

 

[Paul Barker]

I agree with all that.

The internal rate of return, net present value and payback period methods of determining whether to make an investment in industry would all result in failure to invest in a new condensing boiler.

In the same way a heat pump and probably solar hot water heating would fail to get past the finance director as capital projects with sufficient payback.

It is easy to run along with the political tide.

Non of the above incorporates the factor of more frequent and expensive maintenance costs of the new boiler over the old. It isn't worth doing on installation cost against fuel saving alone, add in the maintenance costs and you should definately not renew.

And for the green people, the cost to the environment of using up more precious resources and burning more hydrocarbons to manufacture the replacement boiler cancel your claims out.
But anyway thanks Kyoto for guaranteed work.

 

[plumber (new blood)]

the political issues dont bother me, i just install the things inline with the dam builing regs, after all we don`t make the rule up, thats for the powers that be. all i know is i will install what ever comes on the market if it`s what poeple want..solar systems..heat pumps.. what ever,we`ll all out there just earning a living who gives 2 f==ks about the political issuse.

 

[ziggysoft]

WOW !
lots of info on this subject.
Just to clarify a bit more...

I had a solar system designed for me.
I was quoted £3500 for installation.
Bought everything needed for £1200.Myself and a plumber friend installed it.
Totally self contained inc expansion vessel.It does not connect to any mains or stored water at all.Seperate electrics and lightning rod !
I don't give a toss about the new draconian regs-except for gas installations.It is a license to print money.
I had the system checked by a British Gas engineer and he said the work was top class and would easily pass regulations.
Works perfectly.Very efficient.I haven't needed to use my electric immersion yet after 3 moths.Saved a packet on electricity.
Now I want to save more money on my energy bills for the coming winter hence the need for a new boiler.
i may not even go down the combi route but as I stated earlier i do not wish to put my eggs in one basket and rely on hot water from only one source.

Ziggy

 

[Paul Barker]

I agree I just fit what I have to, but if people want my advice I give it.

 

[plumber (new blood)]

mr ziggy you system requries a `system boiler` to complete it. you can have as many heating zones as you like,i would install an `S`plan with auto-by-pass if your cylinder is unvented. its incorrect to install any other type of boiler to this system.

SYSTEM BOILER=

heat only boiler (that is to say flow and return pipes only)
expansion vessel
filling loop
pressure gauge

all boilers now have to be condensing so you can not choose on that one, standard efficiency boiler can not be installed

 

[Paul Barker]

There are quite a few ways around this situation. You can change the hot water pipework and use only a system boiler or you can use a new combi in the same way you did with the old, and connect the neating side to the cylinder's spare coil. If it is unvented (which it probably is as the idiots who sell you renewable systems at such an exhaubitant cost the payback period is so long it isn't economically viable also sell you an unnecessary extra expense of unvented cylinder when £150 copper open uvented cylinder would suffice especially since energy saving is the professed aim, whereas in reality it'sa all about boosting the shareholders profits and keeping installers happy) you do have to have a zone valve to cut off the heating supply to it in the evnt of a power failure, but that can be added to y plan.

The system boler new dhw pipework would be more reliable and since you probably have solar heat, immersion heat and gas indirect heat you have three levels of backup. No need for a fraught with failure comby boiler. I think is what newplumb meant when he said you must use a system boiler.

If I were you I would stop the check to the solar heating firm on the basis of a misselling scandle at least as big as the endowment policy one.

 

[ziggysoft]

Thanks to everyone who expressed an opinion.
I think I will go for a new condensing system boiler and gain all my hot water from my hot water cylinder - vented by the way.
I don't need a combi just a reliable system boiler.
I only need to re route one pipe to bypass the hot water that is fed from the combi.
All I need now is a reliable boiler that meets my requirements for a 15 radiator installation(7 bedroom home).
Anyone got a particular model in mind ?

Ziggy