Mira excel pressure pulsing

[tosh101]

Fitted new excel biv to replace old excel biv. Same pipework, Tank fed H & C supplies. Approx 4ft head.
Turn on shower, pressure fairly low when set at cold but pressure increases as the temp dial increased. Kind of expect this with a fairly low static head.
But why should the water pressure start pulsing

 

[bab]

Not fitted excels for a while. long shot but can it be changed on the back from high to low presure . as that was the case on one of the mira valves. is your hot water hotter than 60 oC

 

[tosh101]

cheers bab.
I am a plumber to trade, but been out of the game for a while, so a bit rusty on the new appliances. Fitting this for a friend
Not sure about the temp, but I expect it is the same as for the original excel that was in. I'll check the cylinder stat.
Read somewhere about the low/high pressure setting on back of cartridge. Will give that a try next week.

Thanks for the reply.

 

[tosh101]

The cold feed from tank to shower has an old stopcock on it. Do you think I should change it for a full way gate valve to increase flow slightly. Just wondering if the stopcock is causing the cold pressure to be a bit lower than the hot.

 

[tosh101]

OK Pressure fine down at bath level, but rubbish when rose raised to 4 or 5 ft head. But old excel was fine under same conditions.
Could it be that the new excel mixers with all that technology built in just do not operate as well as the old ones