Main 24 E boiler issues

[chortle]

Hi all,
I've just moved to a new place and the boiler is a Main 24E.
A few years old I guess.
The CH works fine and the HW is piping hot downstairs with reasonable flow.
However the highest point of the water pipes is the shower where the flow seems less than enough.
The bath taps and basin taps have reasonable flow, not brilliant I'd say.
The issue really is that when the shower is running the HW kicks in and out. Cycling between them, resulting in an unpleasant hot/cold shower.
I'm going to check the filter and give it a clean out tomorrow.


Any pointers/suggestions please?

cheers

chortle

 

[Madrab]

First issue - perform a static and dynamic pressure and flow test on a cold mains outlet to give you a starting point.

Try running the shower with the head off, does it still do it. Then run another hot tap a little, does it still do it. Is the boiler cycling on and off?

 

[chortle]

Put the gauge on it today it's showing 2.5 bar static. That's taken from the lowest outlet. Outside tap.
Not had chance to do any more tests as at work.. But managed to get hold of water company who's saying my area is only getting 2.17 bar

 

[chortle]

"we aim for at least 1.5bar which is above the 0.7bar legal requirement....." They said when I asked if they'd turn the pump up jokingly...

 

[Madrab]

2.5bar should feed the system without issue if it's sustained, do a dynamic test and check the flow is sufficient.

 

[chortle]

Thanks,
I did a check earlier and I'm not losing much with the shower running.
It hardly drops on the gauge.
I've managed today to get a shower and keep the temp constant, but you can still hear the boiler kicking in and out.
I took the headset off and it still cycles on/off.
I'll look at the flow rate tomorrow but turning the water between full hot and cold on the mixer, there isn't a visible difference in flow to the eye.

 

[cross thread]

check the filters in the shower ,normally fitted in the unions if its a bar shower

 

[chortle]

The shower is brand new.
It's a basic mixer, lever one. I've fitted a few of them before and they've always been good.
I did a pipe flush before fitting the unit. So I'm sure there's no debris in there.
I replaced the old one as it was scaled up, tired looking and suffering the same symptoms of the boiler.
That is what bought me to the conclusion it's boiler/water pressure, flow etc related rather than the shower unit.
I'll check flow rate later.
Thanks