hot water supply problem with Worcester 28 Cdi Combi

[lance]

Just had a Worcester 28 Cdi Combi fitted in 4bed dormer bungalow CH ok
but hot water supply slows stops if a coldwater tap on or toilet flushed etc..
is this normal .. mains water pressure is not exceptional and if others in street watering garden worse..
It is the last outlet on the house mains i.e all the other taps draw before the mains reaches boiler (from stopcock to boiler approx 60 ft of piping) would there be a worthwhile improvement if first inline. this option may be expensive because mains enters on otherside of building..any comments or ideas appreciated.

 

[breezer]

if a tap is turned on when our hot is on, hot turns to dribble (we have a combi)

dont know if its right but ours does do it

 

[joseph77]

Hello there,

ah your finding out the joys of owning a combi

 

[AlanE]

And installed by someone who never carried out the basic checks to see if a satisfactory combi installation was possible.

Alan

 

[Grunt]

I have a W. Bosch combi in my garage and that is the last appliance fed from the cold water pipes but hot water performance doesn't drop off too much when cold taps are operated. However I did put in a 22mm cold supply to the boiler and everything else is teed off in 15mm.
Perhaps you need to see if you can get a 22mm supply to the boiler.

 

[lance]

Thanks, The feed from the first stopcock into the bungalow is 15mm and all the hot and cold pipes are 15mm. I am having an additional ensuite bathroom fitted shortly so there will be even more water demands before the 15mm ends at Boiler. The only way I can get 22 mm to boiler is Divert underground from external stopcock to garage on other side of property and cap original feed, is that feasible?.( Digging across front of property would not be problem all needs redoing anyway).
The boiler installation was carried out in the same way British Gas Quoted, but I didn't use them in the end because they messed me about too much. BG approved installers carried out installation.

 

[ollski]

You need an individual main to your house, the fluctuating pressures on a shared main are incompatible with a combi. Why not look into getting a new main moled in, it's quick and easy with minimal disruption and if it's a replacement for a lead main your water company may connect for free.
What are BG approved installers?, as far as I'm aware the only installers BG approve are BG.