combination boiler in The AnswerBank: How it Works

combination boiler

I have just had a combination boiler installed; you know the one, no inmersion tank or inmersion heater.My next door neighbour tells me that I should have kept the old type boiler as that with the new one if more than one persona is having a shower at the same time and somebody else is using the hot water, lets say in the kitchen the boiler will not cope. Is this true.?

12:15 Wed 17th Oct 2007

parksy

untrue

betterman

you may lose a bit of water pressure if two or more taps are running, but we solved that by having a pressure compensating shower fitted, mine cost about �100 and they run straight of the mains water so more energy efficient and you dont have to have them wired to the electric.

Even if you dont get one of these the loss in pressure is hardly noticeable on newer combi boiler has they have been designed around this issue because people are wanting larger homes with en suite bedrooms and WC rooms downstairs.

And think of the space you now have with that hot water tank been removed, so you may or may not experience a slight drop in pressure but it is a small price to pay for instant hot water.

you can also get kitchen taps that use less pressure because they have a small retractable shower head fitted to rinse dishes and veg etc, so dont go worrying.

Doc_Spock

The old combis were not that good.

A good test is , run hot water tap, then turn cold water tap on.

Is there a discernible slowing down in the hot water flow. On some old combi systems the hot would stop when cold turned on.

Doc_Spock

Hang on betterman, if your shower runs off mains water how the heck does it get hot.

Reverandfunk

I have a combi and have no problems

Doc_Spock

Betterman, taps cannot reduce the pressure, they can only reduce the flow.

betterman

the water is fed through 22mm pipes initially then into a 10 mm hose effectively reducing the pressure needed for steady flow of the shower attachment

Doc_Spock

22ml is for the hot pipes. 15 ml cold.

Most modern types end up as 10 ml feed. This DOES not reduce the pressure it just restricts the flow, try stopping the water with your finger(cold)

The only way to reduce pressure is an in-line pressure reducer.

Generally speaking these taps are quite inadequate for a gravity system. A lot of people have new taps fitted to old system then complain that flow is no good.

Listen to one who fits systems and knows.

betterman

can hardly believe you fit these things, plumbers earn a good wage and here you are sat at your computer.

Doc_Spock

Retired.

betterman

you said you fit systems, should have said fitted. as in past tense.

Doc_Spock

Do it as hobby for friends and relations.

Doc_Spock

About your "mains feed" shower, what heats the water.

Doc_Spock

Don't tell me, it is the combi.

What reduces the flow on either hot or cold side are interchangeable plastic washers in the shower housing.