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Would it be foolish NOT to replace an old-style boiler with a combi?

19 replies

lecce · 09/02/2013 22:03

Have just moved into our new house and it has an old-style boiler with the water-tank/immersion heater for water. The house was built in 1991 and I think the boiler is the original. Before we moved in, we had assumed we would unpdate the boiler and have budgeted accordingly. However, now we are here it seems it may not be the no-brainer we had assumed.

The property has 2 bathrooms and, especially when the dc are older, we envisage using them at the same time quite regularly. The plumber we have seen so far gave us the impression that this may not be possible with a combi boiler.

The house is very warm. We have only moved 5 miles away from our other house, yet have gone from having the heating on all day to evenings only - in very similar weather, so we are wondering whether the new boiler is really essential. The house also needs a new bath (we knew this before we bought) and it turns out the ensuite shower is pretty useless. in addition, there are a couple of carpets that have seen a better days and a couple of big trees that could do with going. In other words, it would be nice to free up some cash for other stuff, but would we be mad not to spend on the boiler while the money is here?

Is a combi a must-have or,are the old boilers really ok?

OP posts:
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Lastyearsmodel · 09/02/2013 22:10

Combis not good in bigger houses with lots of people, afaik. The thing about an immersion is you always have a tank of hot water! Even if the gas goes off or the boiler fails you can still have hot water.

Get it serviced and don't be talked into 'needing' a new one if there's nothing wrong with it.

And if/when you do replace it, you don't have to have a combi - traditional boilers are still made.

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specialsubject · 09/02/2013 22:35

that's it - new boilers must be condensing unless there is a really good reason why not, but combis are not compulsory.

they are great if you have no room for a tank of hot water, or can't insulate it properly, or in other situations. Careful timing of hot water and a well insulated tank, plus an efficient boiler, means a non-combi boiler is not by any means a daft idea. Combis always have a lower flow rate for the hot water.

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FishfingersAreOK · 09/02/2013 23:59

In our previous home (mid 1990s built) our plumber said that as long as we serviced it regularly and budgeted for the odd £100 part to be replaced evry 3 years or so, (something to do with the fan on the top that extracts the fumes...tends to seize up through normal useage and when it started getting a bit noisier you knew it was the year to replace it) his view was it was way better just to stick with the old style. Combi no good for the size of house. Have yoou got a trustworthy plumber you could ask to service it and get an idea of the state it is in?

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PigletJohn · 10/02/2013 00:50

A combi is ideal for a one-room flat with only one person in it.

However it will show its weakness when you try to run more than one tap at a time, even if one is hot and one is cold. If you try to run two hot taps at the same time, then the available amount of hot water (let's say, 12 litres per minute) will be shared between the two taps, and they will get half each (not really, it might be 60/40 or 70/30 or something rather than 50/50) and it will be far worse if you try to run three taps at the same time.

At extra cost, you can variations of combis that partially compensate for this problem.

When you run the kitchen cold tap into a bucket, and time it to fill, how many litres per minute do you get?

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yummymumtobe · 10/02/2013 09:05

We have just put a combi in our new place for the sole reason that we needed to get rid of the hot tank so that we could have a loo in the bathroom (previously bath and sink in one room and separate wc next door which isn't ideal!). Wouldn't have even considered touching the boiler otherwise. I think if a boiler works then stick with it. Our old flat had a boiler that was nearly 30 years old!

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nocake · 10/02/2013 11:13

If your boiler is working well then why change it? Yes a new one will be more efficient but it's expensive.

When you do change it just stick with a conventional boiler. In that size of house I definitely wouldn't be thinking about a combi. We have one in a small three bed with one bathroom and while it runs the shower quite happily it's almost impossible to have a really hot, deep bath. We won't be having one when we move house.

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lalalonglegs · 10/02/2013 11:22

I'd never have a combi in a family house - the horror of having a lovely warm shower and someone turning the tap on in the kitchen so that you are either left with no water or it's freezing cold Shock. When you decide to change (and if the boiler is 20+ years old, it's going to be sooner rather than later) get a boiler and a Megaflo.

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Ponders · 10/02/2013 11:24

while it runs the shower quite happily it's almost impossible to have a really hot, deep bath

that's a problem with your boiler (or your water pressure), nocake, not combis in general. we had a new one installed last year & we always get really hot deep baths - quite quickly too, though I've never timed it.

the only thing that is sometimes an issue is that if 2 people flush loos at the same time, they can't both wash their hands with hot water at the same time. (One can - the other has to make do with cold Grin)

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EdgarAllanPond · 11/02/2013 10:28

new heat-only boiler going in today - old one is 35-40 years old (doubt combi would have made it that old) - right choice for a big house

the ten year old combi at my last house had fixes every year and was already on its way out...shower didn't run well on it at all. hot bath had to be run out slowly.

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weakestlink · 11/02/2013 12:01

We have a 10 year old back boiler with cylinder / tank etc and we were fully prepared to replace it.

We had a trusted engineer come in to service it and give us his opinion on changing it.

He told us not to bother as it is in good condition with plenty of life left in it and that new boilers do not have long life spans. And parts for new boilers are expensive.

I would get it serviced by someone you trust and if it ain't broke don't fix it! And when it does eventually go - don't go for a combi if you want to use 2 bathrooms at once. They are not suited to large family houses.

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toughdecisions · 11/02/2013 12:07

Our plumber said not to replace old boiler until it ceased working for same reasons as weakest's.

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PigletJohn · 11/02/2013 12:15

I moved from an old iron boiler to a good modern condensing heat-only boiler with a HW cylinder. It is much more efficient and I was surprised that it knocked about a third off my gas usage. However it will take quite a few years to pay back the cost of change, so it would not have been worthwhile if the old boiler had not developed a severe fault due to age and rust.

BTW when you put a new boiler on an old system, it is important to have it powerflushed as it will usually have a heavy load of sediment, and to fit a system filter to trap the circulating particles to prevent them building up into a new blockage. Some designs of modern boiler are easily clogged, and dirt is not covered by the guarantee.

Modern combi boilers are relatively complex and have a lot in them to go wrong.

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ouryve · 11/02/2013 12:17

For us, it wasn't the early 90s boiler that gave out. It was the hot water tank which sprung a leak - all over our bed.

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PigletJohn · 11/02/2013 12:31

easy to fit a new cylinder.

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RunnerHasbeen · 11/02/2013 17:16

When we replaced our boiler and filled out a form for the subsidy there was an on-line measure of how efficient the old boiler is, maybe you could check yours and then decide. Or have someone round to service it, so you know what you are dealing with - no need to replace unless there is a good reason to. Our boiler was off the scale inefficient, but it was from the 70s, so I'm probably not the best judge ('91 sounds fine to me)!

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PigletJohn · 11/02/2013 23:17

you can look up the efficiency rating of your old boiler on here or similar sites. You need to know the manufacturer and the precise model.

My old iron boiler from about 1981 was 65% efficient and my new condensing (conventional) one is 90.1%

My mum's old boiler from about 1990 was 73.9%

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LittlePushka · 11/02/2013 23:37

We changed when we extended. Best thing we did - genuinely Smile

more efficient, always hot water, shower is itself thermostatically contolled so that calls on the water do not affect its temperature and almost imperceptible drop in pressure. House is a large three bed farmhouse, heats whole house radiators, water and underfloor heating easily.

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ouryve · 12/02/2013 00:03

Haha Pigletjohn - not in our loft, which had been given a new roof and ceiling below, with rather small loft hatch, since the last water cylinder was fitted! There were already 3 dead ones in there. DH eventually cut 2 of them into pieces to get them out.

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kittycat68 · 12/02/2013 15:17

had several combis in serveral houses four adults in our houses 4-5 beds and always had hot water on demand no problems with flow rates etc. costs about a third less a year to run. Alot of heating engineers dont like them as they have to retrain to fix and service them and find them complecated so dont bother. the manufatures always have a list of reilable engineers in your area that are trained to servive and mend them. so dont be put off.

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