Domestic Hot Water Boilers.

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Thu 8 May 2014 17:18
Domestic Hot Water Boilers. - Peter

We are soon to replace our current gas fired boiler and immersion heater as they are over twenty years old and inefficient.

The question is, with modern systems do I need another immersion heater or will an instant hot water boiler do?

It will need to heat the radiators (14) in a four bed house plus supply hot water for showers, baths and various sinks.

All comments appreciated.

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Thu 8 May 2014 20:58
Domestic Hot Water Boilers. - FP

"...with modern systems do I need another immersion heater or will an instant hot water boiler do?"

My system is not instant - it's a pressurised system with hot-water storage (i.e. the tank in the airing cupboard), which has an immersion heater - useful if the boiler fails, or for topping-up the temperature during the day. In fact, the immersion heater get used very little.

If you go down the "instant hot water" route, you won't need a storage cylinder and therefore won't have anywhere for an immersion heater. Or you could replace your old boiler with a more efficient modern one, keep the storage cylinder and also replace the immersion heater.

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Thu 8 May 2014 21:54
Domestic Hot Water Boilers. - gordonbennet

Whoa, hold on.

Our combi is about 22 years old now, and we thought (having been told this regularly) that our old inefficient boiler was on its last legs and costing us a fortune to run.

Luckily we've now got an old school chap who does nothing but boiler maintenance, repairs and supplies and fits the same, he's like my old school Mercedes indy, he believes in fixing and maintaining good older products well.

Anyway we had a heat exchanger leak, the chap came and fixed it, and i asked him to be brutally honest about our old boiler.

His answer, they really do not make them like ours any more, its a Vaillant, its still in good condition, it works well, he can still get parts for it, and he reckons it will last longer than any new one he fitted today.

Our only problem is our bungalow is very long, and there's an awful long run of pipes from the garage (boiler lives) to the kitchen at the other end of the house, we keep meaning to get an undersink electric hot water unit fitted, which holds about a gallon of hot water, in winter it can take about 2 minutes for hot water to come through from when you turn the tap on, thats the only drawback with full combi.

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Thu 8 May 2014 22:56
Domestic Hot Water Boilers. - daveyjp
You need a registered installer to visit, undertake a full survey and advise you of your options.

Chances are with such a large property an instant hot***er system such as a combi boiler may not be sufficient if you have a need for hot water at more than one point at the same time. However some higher output combis have on board hot water storage tanks which give 20-30 litres of hot water.

Vaillant website has a system chooser which will help you decide.
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Fri 9 May 2014 23:39
Domestic Hot Water Boilers. - jamie745

14 radiators?

How big is this house?!

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Sun 11 May 2014 16:44
Domestic Hot Water Boilers. - Peter

Too big when it needs painting.

Four bed detached, dahn sarf.

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Fri 23 May 2014 15:55
Domestic Hot Water Boilers. - concrete

I agree with gordonbennet, my boiler is 9 years old and a recent service and full efficiency test revealed it is 97.5% efficient. Pretty good really. The question of hot water needs thinking about. The main drawback with using instant supplies direct from the boiler (combi) is if there is more than one draw off demanding at the same time. There is only so much pressure through the water main and the more demands then the pressure drops dramatically. In a larger house and for a consistent pressure for supply cold water storage tanks are the answer. Fit them as high as you can get them in the loft (height equals more pressure for gravity feed) and they will supply hot water storage cylinders and showers at a constant pressure, even when more than one draw off is demanding water. I store 200 litres in my loft and the pressure is great without a pump for showers. So what you probably need is a modern and reliable i.e Vaillant or Viessmann system boiler (not combi) which will easily feed 14 radiators and a fully pumped hot water storage cylinder with a high heat recovery internal coil. You can also fit an immersion heater into this for emergencies.

Best of luck. Concrete.

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Fri 23 May 2014 00:50
Domestic Hot Water Boilers. - Leif
A combi is good, but your house may be too big, with too many people wanting hot water all at once.
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Sun 8 Jun 2014 11:34
Domestic Hot Water Boilers. - sandyyy

Domestic hot water boiler is very good for boiling water and take bath with that boiling water. It is of both type - a boiler which can run from electricity and a boiler which runs from sunlight. But for domestic purpose mostly boiler which uses electricity is used.

(Link deleted)

Edited by Avant on 08/06/2014 at 15:19

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Mon 9 Jun 2014 22:37
Domestic Hot Water Boilers. - FP

What d***** these people come up with - why not just post the link? We're not interested, but it would be quicker.

"Domestic hot water boiler is very good for boiling water..." It doesn't boil the water. It heats it to a lower temperature than that.

"It is of both type - a boiler which can run from electricity and a boiler which runs from sunlight..."

The process by which water is heated by sunlight does not involve a "boiler". And I'm pretty certain an electric "boiler", as such, is a rarity.

"But for domestic purpose mostly boiler which uses electricity is used."

No - mostly gas, followed by oil and then liquid petroleum gas.

I don't know why I bother - "sandyy" won't be back and he wouldn't comprehend anyway.

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Mon 9 Jun 2014 22:38
Domestic Hot Water Boilers. - FP

What d***** these people come up with - why not just post the link? We're not interested, but it would be quicker.

"Domestic hot water boiler is very good for boiling water..." It doesn't boil the water. It heats it to a lower temperature than that.

"It is of both type - a boiler which can run from electricity and a boiler which runs from sunlight..."

The process by which water is heated by sunlight does not involve a "boiler". And I'm pretty certain an electric "boiler", as such, is a rarity.

"But for domestic purpose mostly boiler which uses electricity is used."

No - mostly gas, followed by oil and then liquid petroleum gas.

I don't know why I bother - "sandyy" won't be back and he wouldn't comprehend anyway.

PS The swear filter doesn't like d r i v e l, it seems. My upbringing must have been very sheltered.

Edited by FP on 09/06/2014 at 22:39

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Tue 10 Jun 2014 01:30
Domestic Hot Water Boilers. - Avant

He certainly won't be back under that name as he was trying to advertise and I've disabled his account.

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Mon 16 Jun 2014 21:57
Domestic Hot Water Boilers. - Cyd

The process by which water is heated by sunlight does not involve a "boiler". And I'm pretty certain an electric "boiler", as such, is a rarity.

I'm guessing you live in a large city and rarely venture beyond it's border?

Here in SW Leicestershire, gas is only available in the large towns. Anywhere else and you are stuck with electric only unless you have oil (very few have LPG). Many many houses are all electric, some with storage heaters some with wet heating with electric boilers. Electric boilers are small and quiet and with no moving parts also reliable. Expensive to run, yes. Some houses even have electric combis - horrendous devices, very expensive very complex and unreliable.

I imagine this situation is replicated in most rural areas.

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Sat 14 Jun 2014 21:45
Domestic Hot Water Boilers. - AlexT

I have this system setup : sun hot watter pannels for the summer heat the water in the big tank in the summer. and wood gaseification burner in the winter. Plus a little electric thingy that heats it in the 2-3 days in the summer that don't have any sun. I found this is the most energy efficient way, and the cheapest way. I would NOT put a gas heater now since gas is likely to go up in price, or so the gossip is around here.

Edited by AlexT on 14/06/2014 at 21:54

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