Can Hot Water Storage Cylinder Be Used with Combi Boiler?

[marconi]

[

I have very recently had my old central heating system removed completely
and replaced with a new installation of a Combi Condenser boiler with all
new radiators and all pipes upgraded from 6mm to 15 mm. The hot water
storage cylinder and replenishment tank have been disposed of.
Despite the forseen advantages of this upgrade, the abscence of the hot water
storage cylinder results in an increased delay in the flow of hot to the taps and
half a basinfull of Cold can be wasted before getting a basinfull of Hot water.
Apart from the delay which is acceptible, I expect my METERED water bill to
increase substantially due to the waste.
So, my question for those in the know is: can a Hot Water Storage Cylinder be
somehow incorporated into a Combi Boiler system to improve performance or
is this a daft, incompatible idea? I'm imagining a storage tank in between the
boiler and the Hot flow pipe to the taps, which would be topped up with Hot
from the boiler every time a hot tap is run. Obviously, no need for a Cyl stat.

 

[doitall]

Not a problem.

Recently fitted an Intergas at my Daughters. Connected the combi serving the kitchen and utility with a cylinder on a Y plan serving the bathroom.

 

[holty]

seriously. have you just come back from the pub. joking aside. why. if the wastage bothers you that much then try this http://controls.tedcon.com/combisave.php

 

[Dan Robinson]

The OP is thinking of a hot water buffer tank on the mains AFTER the combi boiler.

From what I can tell anyway...

Find one under 15 litres and happy days... otherwise it will get complicated very quickly.

 

[holty]

DIA i think the OP is actually suggesting on having a cylinder inline with the combi dhw outlet, to acctually get hot water quicker to the hot taps on all outlets. and not a case of e.g kitchen fed tap of combi. then rest of the house unvented cylinder. maybe reading this wrong if so i apologies to all

 

[gas112]

OP the cost in wastage of water is outweighed in gas saved from not heating a full cylinder off water everyday

 

[doitall]

Buffer tank, store, cylinder, it would still need to run off the htg side of the boiler.

If there were long runs you could fit a heat bank, near the outlets, but even that would have to come off the htg side.

 

[Dan Robinson]

Hence zone valves, timers, thermostats wiring, space...

The OP has a slightly skewed idea about water usage/gas usage which is not uncommon.

 

[doitall]

One of the biggest problems and causes for wasted water is keeping the 22mm pipe instead of downgrading to 15mm.

 

[holty]

if water usage was that much of a problem to people. then they could use the water draw off into a bucket. isolate the toilet. then pour the waste water into the cistern. then if a top up needed turn on the iso valve. same can be done with having a shower in a bath. keep the plug in then reclaim the waste water. now this is showing my northern routes. "upstairs for thinking downstairs for dancing"

 

[marconi]

Thanks for all the quick replies. My internet searches show the combi water wastage to be a big issue globally but of little interest to many.
The suggested "CombiSave" device has attracted my attention and I will
take a look at it.
Why can such a device not be incorporated in the boiler unit at manufacture? My boiler is a Potterton Promax HE Plus Combi 28 HE A.

 

[Agile]

There was a flow limiter fitted to the Potty Puma boilers. They did not use it on any later models.

It was a design error because it was added to ALL Pumas instead of just the small proportion ( 10% ? ) with electronic ignition.

On the ( 90% ) pilot light models, the large heat exchanger was kept hot by the pilot light and so could give instant hot water.

Tony

 

[Agile]

Are your hot water pipes in 15 mm ?

Do they take a short route or go through the loft?

Are the insulated? Only a very few installers ( me ) ever seem to do that.

Tony

 

[mysteryman]

Meanwhile, you can learn quite quickly the trick of turning the hot tap on just far enough to bring the boiler on in hot water mode. Run the tap at this slow pace until it runs hot, then increase the flowrate. Combis are different, that isn't necessarily worse.

 

[marconi]

Agile. Yes,15mm. Short route, not insulated.

Mysteryman. Noted what you say and doing it.

I should point out that the delay is not excessive and is no inconvenience to me. Visitors may ponder a bit when washing hands after using toilet or whatever. I have researched the CombiSaver device on a few forums and
it appears to only do what Mysteryman suggested (control the flow rate),
which makes it a wasted expense. So, I have decided to live with the downside of a combi and enjoy the upside but I do miss the airing cupboard drying facilitated by the HW cylinder, especially in this lousy weather. Thanks guys, for your contributions.