Combi boiler-How do they work?

[dizzymizzy]

Hello,

I hope you can help deceifer my post as I'm a little confused. I've just taken possession of a brand new house and I'm not quite sure how things work. I'll describe below.

There's a gas boiler in the kitchen. I think this supplies the heating only.

There's an emersion heater in the middle-floor airing cupboard. Also in the cupboard is a little red round tank about 1' round and high.

In almost all houses that I've been in before, if you turn the hot tap on then the boiler fires up and hot water comes out. I'm read some of the blurb on the net which describes the different types of setups, eg. 'system' configuration.

Here's where I'm getting confused. I have the emersion switched off on the wall, and with the central heating on for a few hours, if I then touch the pipe on the emersion heater then there's hot water in there.

There's a panel in the airing cupboard which controls 'hot-water' and 'central-heating' in a similar way to what I've seen before.

Should hot water be being supplied by the gas boiler? Is the gas boiler inadvertantly heating the water in the immersion heater?

Bit worried if this is going to be expensive if I need to have an emersion on for hours to get hot water.

So confused.

Thanks

 

[EliteHeat]

You do not have a combi boiler. You have a boiler that should provide central heating and hot water. The hot water comes from the cylinder in the airing cupboard. The immersion heater is a backup device in case the boiler fails. It is usually more expensive to heat water electrically than via gas, but who knows - that might change. The important bit is that the immersion heater and the boiler are heating the same water that comes out of the taps.

 

[Paul Barker]

It's a sad refelection on the state of our industry when people can't recognise what was and should still be conventional.

 

[dizzymizzy]

It's a sad refelection on the state of our industry when people can't recognise what was and should still be conventional.

Is conventional a type of system for heating the water? Sorry, boilers I can't do, bringing up kids to respect others I can.

 

[Agile]

I dont think its a sad reflection on anything apart from how anyone can buy something as expensive as a new house without the selling developers sending someone to explain how the heating works!!!

Tony

 

[ChrisR]

"Conventional" just means the sort of system you've got, with stored hot water, as opposed to a combi-boiler type. Paul's a bit of an old fart and likes things the way they were. You'll be happy you have that immersion heater in the cylinder, if the boiler fails; there's no backup like that for a combi.

By the way, by the red blob tank you should see a small gauge which has a black needle indicating about 1 bar pressure, "bar" being the unit.

 

[dal5band]

The little red tank dosn't sound conventional to me - I persume it's an external expansion vessel ? Instead of a little header tank in the loft ?

 

[Paul Barker]

Your question has just reinforced what a massively effective force the combi brigade has been.

The manufcaturers have now decided that unvented cylinders are the way forward, having realised they can't make a bullet proof combi economically (though others can).

You have a cylinder (which you might think is a boiler) that gets all cosy and warm, so you have a new concept to you, somewhere to put the kids clothes between washing machine and chest of drawers (or some suspended canvas Ikea construction in your case most likely).

You have the luxury of hot water that will come out of more than one tap at a time, and that you can still heat upo at the flick of a switch if your boiler brakes down though now that it's much less complexed it is less likely to.

Your system has been turned into a sealed system by a very clever installer. You want to find that guage and a filling loop before it's too late and you're calling an emergency plumber, who will be disgusted at yet another person who doesn't know about filling loops.

I do fit combi's for the ignorant who don't catch the importance of what I'm trying to say, well if I don't someone else will!

 

[Softus]

Paul, do you believe that there are any circumstances when a combi is the correct choice for the circumstances? For example, a ground floor flat that has no loft space and no shared cold storage cistern?

 

[kevplumb]

or a five bedroom house wiv 1 miserable old scroat living there

 

[Paul Barker]

Softus, if there is room for a Brittony II no, if there isn't yes.

 

[Paul Barker]

Kev, definately qualifies for an airing cupboard. No way should he have a combi. Actually I'd keep his back boiler going.

 

[RichA]

What is a "Brittony II" and why would this be better than a Combi?

Thks,

RichA

 

[chrishutt]

Haven't you heard of Google. Do a search on Britony II.

 

[RichA]

My research of Brittany II's led me to believe that it was a water heater and not suitable for also carrying out the task of central heating. So that would mean having a water heater and a boiler? Not ideal in a small flat?