Central Heating Advice Please

[securespark]

Hi Folks

I have a wheezy old system that is costing me dear. I have just swapped from Npower to M&S energy on the advice of uswitch. Npower were charging me £221/ month for dual fuel on a 5 bed det.

It's an Ideal Mexico with 12 rads, basically gravity-fed but with a couple of valves under the floor (don't understand much about CH wiring....)

It dates back to about 1982.

I would like to install a Worcester system, but don't have a single clue where to start, save to say I have searched a few posts here and I know Combi's are rubbish if you want to open more than one tap at the same time.

Being a five bed, 2 bath 5 person household, with kids 14 and under, we use a lot of heating and HW.

In fact, the bathroom was refitted last year with a separate shower and sometimes the bath taps and shower are running together.

So, we need a boiler system that gives us lots of hot water!

I love the principle of a Combi where you ditch the tanks and cylinder and have limitless HW on demand, but they don't give multipoint use.

A system to replace what I have seems the way to go:

Greenstar FS 42CDi Regular

Although there is a "System" boiler they do that does away with the need for the storage tanks: I'm not au fait with this type of boiler.

My only worry is my water pressure. I'm not sure it's the best. I know Regular systems can work on low pressure, but if the 42CDi throws out 25lpm, it can only do that if the water is available on the incoming side.

Now, I know pressure and flow rate are related but are not the same.
However, without the aid of a pressure gauge that I can fit on my outside tap, I went to United Utilities website and they told me that my water pressure would be "poor" if I could not fill a 4.5 litre container in 30 seconds.

Well, it filled in 22.5 seconds, but does that tell me the pressure is good? I suspect it also varies too.

That flow rate equates to 13 litres a minute.

Do I need to get my supply looked at?

And, finally, given the age of my system, should I change the rads as well, or will a powerflush suffice?

Thanks guys.

 

[GavThePlumber]

Definitely not a combi and I wouldn't go with a Worcester either, you have watched too many TV adverts Many better boilers on the market.

You should be looking into an unvented cylinder, probably 300l and adequately spec'd system boiler.

 

[Hugh Jaleak]

Another downside of a combi is, should it break down, then you've no hot water or heating until it's fixed. Keeping stored hot water does offer the benefit of being able to fit an immersion for use as an emergency measure to get some hot water!

Decent boiler with a cylinder offering a quick reheat time should manage your hot water requirements, but i'd do a bit more research before committing to the expense of getting it all changed, seen a number of posts where people are not achieving the savings on the gas bills they were expecting.

System boiler offers pump, expansion vessel etc all within the boiler. Working on a 'sealed system' it negates the need for cisterns, and simplifies the installation.

Think of heating wiring as a series of switches. Programmer switches power on to the system at the set times. Power then travels to the stats (roomstat and cylinder stat), if these are calling for heat they switch the power through to the motorised valve motors. Valve then opens, activating a microswitch, which in turn sends 240v to the boiler and pump for them to operate. Good Y and S plan animated diagrams here if you're interested: http://octaveblue.co.uk/c_heating/index.htm

 

[securespark]

Thank you very much, Gents.

The only reason I have chosen Worcester is nothing to do with TV. Most of my product choices are arrived at with the help of Which?

Hugh: thanks for explaining a "System" boiler, but what's the difference with a "System" boiler that does away with the water storage tank?

Or have I got that bit wrong?

Thanks also for the wiring plan link.

GTP: which brand would you go for if not Worcester?

Cheers guys!

And what about my water pressure and changing the rads?

 

[Madrab]

Apols, wrong post

 

[securespark]

No worries, I've done exactly the same...

 

[dcawkwell]

Stick with what you have. Ensure you have thermostatic valves on the radiators, loft insulation and a wall thermostat. Also a tank thermostat.
The existing boiler you have will still be going when any boiler you put in is being replaced as scrap.

 

[xr4x4]

Given you don't have very good water pressure, I don't know if an unvented hot water tank is your best choice. Is your current hot water cylinder ok?

All a unvented will give you is mains hot water, all this means is you don't need pumps on showers and a cold water tank.

How many showers do you have and how are they fed? Do you have any pumps.

If your boiler controls are fine, pump, expansion vessel etc stuck with a heat only boiler. If they aren't, get a system boiler.

A system boiler will be pressured/sealed and remove the need for a tank for the central heating, a heat only will need one, unless you convert it to a sealed system.

 

[Hugh Jaleak]

A new boiler may take many years to payback the upfront cost, (if at all before it needs replacing!), whilst the Mexico is still going I'd keep it! You are likely to achieve better savings making more efficient use of what is there. Preventing heat loss is key, check insulation levels etc, and thermostatic controls on the system to ensure maximum efficiency.

FWIW i'm paying £126 a month for duel fuel on 2 bed Victorian Terrace with Eon. Loft insulation is up to spec if not above, all windows/doors are uPVC replacements, and we use open fire in living room during colder periods, to ease the load on the boiler.

Boiler is a 50000btu SE, heat only on a fully pumped system, cylinder was replaced with boiler in 2004. Trying to reduce electricity consumption by trying to persuade teenage stepson to TURN THINGS OFF when not in use...... (He is currently 'on one' as was asked to turn his music down at midnight last night as his mother and I, (never mind the neighbours) were trying to sleep.....

 

[securespark]

Guys...

Thank you all so much for your input.

It looks like you're advising against replacement while I don't have to, but if I am forced, then, because of the poor pressure, replace like with like, is that correct?

Hugh, my bill is now around £140 per month. We have cavity, loft and uPVC
but although we have a fire in the lounge, we don't use it (it is gas anyway).

My biggest bill must be for HW, so I think I'll look into alternative methods.

Woodburner???

But, on a more serious note, could you supplement your water heating with Solar or other methods?

Is it effective? Cost-efficient?

 

[Agile]

Which are not very fair with their product reviews!

For a start, I have read that they charge the manufacturer for including their product in Which listing.

Then Which use their own subscribers to provide their reliability data.

They are upper class people who can afford to buy the best and employ good installers. With boilers the installation has the biggest effect on the reliability.

Tony

 

[Hugh Jaleak]

Twin coil cylinder I believe would allow solar to supplement boiler for HW, although I cant comment on cost efficiency. Unvented is restricted by incoming mains supply, as is a combi, you cant get out any more than is coming in without upgrading mains supply. Bear in mind filling a bath or taking a shower will draw from hot and cold supplies, thus limiting the amount that can be drawn off to the limits of the incoming supply. Combi's can also struggle with HW at this time of the year when the temp of the incoming mains supply is lower.

Either heat only or system boiler would be ok for replacement, but with the reliability of modern boilers seemingly rather poor, it's likely to be false economy to replace an existing boiler that may well offer many more years of satisfactory service (if looked after and maintained!), when the expense of doing so may prove slow (if at all possible) to recoup.

With the traditional idea of stored cold water in the loft it offers the benefit if supply is poor, that a quantity of hot water can be drawn off, e.g a bath, giving the cistern time to refill whilst bath is in use. Modern cylinders can offer a fast reheat time, (20mins) so should keep up with most domestic hot water demands.

 

[securespark]

Thanks.

Hugh, WRT your last para, I don't think my system is as quick or efficient as that...

I think sooner, rather than later, my boiler will pack up.

Assuming there's a piping problem, do you have any idea how much it would cost to upgrade the supply into the house, in order to improve the supply?

 

[D_Hailsham]

it filled in 22.5 seconds

Did you check it at the kitchen cold tap? If so, some taps restrict the flow, so it's better to check at the outside tap.

 

[Hugh Jaleak]

Water companies used to offer a service whereby if you ran a new supply to the boundary (provided it was laid/fitted to spec) they would then connect from that point to the main free of charge. Depending on how long the run is from the property to the road, digging a trench, laying a new service etc could be DIY'ed if you wished, check with water co. what the arrangements are regarding connection.

Do you know what the existing supply is? Lead services were laid when demand on water was not so great, and in some areas it can often be branched off a lead rider main that feeds a number of properties. However, any replacement of black 'alkathene' is unlikely to offer any noticeable benefit.

On commissioning of any new service the existing must be capped to prevent any 'dead legs'. Usually straightforward if a single supply, water co will abandon it at the main end, you simply disconnect and cap it inside the property. However, if branching off a shared supply it would have to be capped externally at the branch.