Combi-boiler? Megaflow? system boiler? help!!!!!!

[tostaky]

we are renovating the flat we just bought and need to replace the water/heating system...

There are two of us and 3 little boys. 1 bathroom, 1 wet room, 2 toilets.

what do you have? are you satisfied? pros and cons?

thank you

We have a combi boiler, it's Eco friendly so If I can remember rightly we got some money back for installing it, this was 5 years ago. It also doesn't take up too much room.We have 1 bath and 2 showers, the downside is that we can't run 2 showers at the same time, even though one is electric. This has never been a problem though.
Our boiler was installed on pre existing radiators and managed to get clogged up with sludge quite expensive to fix and avoidable if you have a magnetic filter thing fitted. :)

we just had a new combi boiler fitted last month - we have a bathroom & a shower room.

the old boiler (very old!) was leaking through a part that was only replaced last year, so British Gas said that meant the system would be full of sludge & that as well as a powerflush we should have a magnety thing installed - total quote (including upgrading some pipes to a larger diameter) was £4,500

but we had a local plumber fit it; he said the water in the system was perfectly clean, we didn't need the magnet (which BG quoted about £350 for, but he said they're under £100 ), & for a more powerful boiler than BG's quote - which is wonderful compared with the old one, which really was on the way out - the job cost just under £2000

so don't get BG to do it

ours is \link{http://www.worcester-bosch.co.uk/homeowner/boilers/gas-boilers/greenstar-30si\Worcester Bosch Greenstar 30Si} - the boiler itself cost around £1000. Worcester Bosch & Vaillant are the best boiler makes; they cost more than others but are definitely worth it

although their description says suitable for 1 bathroom homes, the Which report said:

'Its heat output of up to 30kW makes this boiler suitable for small properties, such as a flats and semi-detached homes with a single bathroom and perhaps an ensuite'

& we're finding that's true. It's always tricky running more than one hot tap with a combi boiler as the flow has to be shared but the flow on this one is massively better than the old one

Vaillant are great boilers: we got a condensing boiler last year after living with a 40 yo thing the size of the washing machine for 7 years. We now have the Vailant ecotech pro. It is fantastic and has changed our lives - really. No more tossing a coin for who gets the warm shower and who gets half a cold one etc.

It was about £2k for boiler, installing, removing the old boiler, header tank and hot water cylinder etc, system flush and replacing 2 radiators. FFS, don't go with an energy supplier. They will charge you silly amounts: our cheapest quote from BG was about £4k.

Also, DH works in social housing and Vaillant are the make they use because they don't break down.

When you fit a new boiler on an old system, there is very often a lot of old sludge and sediment, and even a good powerflush won't get it all out, so there is a lot to be said for a system filter that will trap the remaining particles. If they get into your new boiler (especially a combi) they may partially or completely block the heat exchanger, and they will cause premature wear in the pump and other parts. Sediment damage is not covered by a boiler manufacturer's guarantee, since they delivered it clean.

A filter can be bought for about £100, and is trivial to fit when installing a new boiler.

The Magnaclean was the first mass-market one and is very effective, but is made of plastic and prone to leak after a couple of years. I prefer the Spirotech one which is made of brass and much better quality. Sentinel make a copy very similar one.

Piglet - thank you for that! We are doing up the whole flat so it is going to be an entirely new system, new radiators, new pipes so sludge won't be an issue.
Might still be worth installing one of those magnetic filter though,

Thanks all - I can see that combi boiler are a favourite!

measure the water flow at the kitchen cold tap by seeing how long it takes to fill a bucket, and make sure you have at least 12 litres per minute, or you will find a combi disappointing unless you replace the water main with a larger pipe.

Piglet - we definitely haven't got a lot of pressure... When I run a bath, there's no water in the kitchen. That's why we were thinking about a megaflow.
Not too keen on a system boiler cuz I don't want two tanks (one cold, then one hot plus a pump). A megaflow is only one tank isn't it? And we can hide it in the loft as there is none of this negative pump business thing? Or is there?
Also is it not very expensive to dig up the mains and change the pipe? Would that be enough to solve our pressure problem?

A megaflow and a combi are both dependent on the amount of flow (not just pressure) coming into the home, since there is no stored water.

A megaflow is very heavy when full, and needs to be regularly inspected and possibly serviced by a qualified persion for safety reasons, so the loft is not the ideal place. It does not have to be upstairs.

Laying a new pipe will cost at least a few hundred, possibly more depending how much digging is required, and whether it is through garden soil or concrete, and if you have to take up floors inside the house. If necessary you can have it "moled" by a contractor with a machine. The water co will usually charge you to connect it under the pavement, unless the old pipe is lead or you are having a meter fitted, when you may be able to get them to connect to your new pipe at reduced or no cost, provided yours is already for them. The pipe must be laid at the depth they specify to protect from frost or spade damage. New blue plastic pipe is not at all expensive so you may as well lay a 25mm or 32mm as it is not much more than 20mm.

If you have lead pipe come back quickly as there are extra things you can do to get a subsidy.

how do i know if i have a lead pipe?
also, we are on the first and second floor of a midterraced house. i am assuming that if we have to dig, then the people on the ground floor will be affected? and that i will need agreement from their landlord (who lives in greece andis very difficultto contact). presumably the water mains come through their flat first and then onto ours?

so really, in terms of simplicity ofoperation and maintenance, space saving and pressure,the best option would be a combi boiler with a bigger pipe from the mains?

Really not keen on the "system" solution unless we can have both hot and cold water tanks in the loft + the pump. but then we would get drinking water only from the kitchen sink which is a big disadvantage (my kids just drink water when they brush their teeth or sometimes the bath water )

or the other solution would be a combi boiler, dont touch the pipes and have power showers fitted? what if someone is havinga shower while the washing machine is on and i open the water in the kitchen? will there be no water in the kitchen (as now) because the power shower and washing machineare drawing too much water?

it sounds like it will be quite difficult to replace the pipe as you are not on the ground floor. If it is a conversion, there might be a single incoming main supplying both flats. You might get agreement more easily if both flats are done at the same time.

you can tell if it is lead by looking at it, and scraping it. Apart from paint, it will usually be dark grey but silver when scratched. It will be soft enough to bend by hand. Lead pipe is common on houses built before about 1920-1930 but it varies by area and might already have been replaced.

Power showers have pumps to suck the water through. You can use them on water from tanks, but not the main.

Combis take their water from the main, so if incoming pressure and flow are poor, you will not get much.