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KD1 · Joined: 27 Mar 2008 Posts: 2 Location: ENGLAND

The section I am on at the mo is Instantaneous Hot Water Systems and the begining of the introduction sats "Instantaneous systems work on the basis of passing cold water from the service pipe through a heat source, which heats the water by the time it comes out at the outlet........ It says the types on instantaneous heaters include:

*Single point
*Water jacketed tube heaters or thermal stores
*Multi point.

Now my question is We have a combi boiler which (multipoint and central heating) and the water is not hot by the time it comes out of any outlet in the house as the introduction says is there a problem with my boiler then? It usually takes 1 minute maybee longer before hot water comes through the outlet? Any help on this much appreciated KD1

thescruff · Moderator Joined: 03 May 2003 Posts: 4419 Location: Bath

You open an hot water outlet, and the boiler heats the water, how long it takes to gets hot at the outlet depends on the size and length of the pipe.

For example an outlet 2m away will get hotter quicker than an outlet 10m away, by the same token an outlet in 22mm pipe will take longer than the same outlet in 15mm pipe.

Being a good plumber is all about lateral thinking when you're on the job, you have to think and work it out practically, every job is different, your question is typical and quite obvious if you put the brain in gear. the heat has to get from A to B, exactly the same as the radiators.

Ask questions by all means but suggest answer as well.

KD1 · Joined: 27 Mar 2008 Posts: 2 Location: ENGLAND

thanks for your reply i could of worked it out ah well am creamcrackerd and got caught up in my thinking on this after just reading about single points where the flow rate is reduced so the water can be heated up from the outlet and was mixing this idea up and forgetting about the length of pipe from the combi to an outlet an the water running of from this before the hot water reaches.. It still does seem a long time though in the kitchen and the boiler is only in the next room not much pipe work.