New combi boiler - big loss of water flow - help or advice please!

[ezi]

Hi,
Ive recently had a new Worcester Greenstar CDi Compact boiler installed in my attic at the same time as having a loft conversion. Long story but there was not enough pressure to run anything in the house so eventually the waterboard replaced the meter, and mains from the road to my house. Am now lucky in having 4.5 bar pressure and 22 flow which apparently should be fine.BUT - i cannot run two taps at once in the house without the water almost drying up; the water coming out of shower is a pathetic dribble. There seems to be no explanation for it and has 3 plumbers stumped - do you have any advice or possible solutions? Has anyone come across this before? I expected a loss of flow from the taps once i switched from a tank to a combi but this is ridiculous is not really workable with a busy family. Help please

 

[gasmanrob]

4.5 bar is amazing pressure and 22mm will give good flow under that.

However pressure and flow rate aren't always related. I suggest that somewhere you have a restriction in the pipe work as a restriction won't effect pressure.

What's the flow like at the cold on the kitchen tap?

Was the mains flushed when the water board did the change over as you may find grit has entered the system and has collected somewhere. Good indicator is remove the filter at the kitchen tap and see if it's full of stones.

 

[jonnyswamp]

You say 4.5 bar, is that static or dynamic and whats 22 flow? do you mean 22lpm flow or that the supply pipe work is in 22mm
You need to test static pressure, working pressure (dynamic) and flow rate in lpm (litres per min)
and post back

 

[Scott_D]

Is it the same from cold tap and hot?

 

[Destroyer2813]

What model cdi ? So we know what flow rates you should be getting

 

[AWheating]

combis are really a one tap appliance. Worcesters have a flow restrictor on the cold inlet to ensure the correct flow rate giving the correct hot water flow. The boiler will only give a certain flow rate. Normally between 9 and 16 depending on the size of the boiler.

if you get the designed flow rate from the boiler and are unhappy you have 2 choices, 1 change the boiler/ hot water system. 2 fit flow restrictors to the taps and pipe cold to boiler as first tee off cold main.

good luck.