cold water storage tank install now water pressure low

[goateater]

Hi folks, just replaced an old cold water storage tank and replaced it like for like
except the origanal one had the feed outlet under the tank and now the outlet is on the side, the pressure now at the hot taps & the electric shower is noticely lower than before, is it simplely that the weight of the water is less because feeding from the side and not the bottom, ?
I've cleared an air lock we had in the hot taps but still lower pressure than before

 

[Johntheo5]

Is the height of water in the new cistern the same as the old, ie, is the LXB the same and is the outlet the same bore/fitting as the old?

 

[goateater]

yes Water level the same and outlet bore the same
only differance is outlet is 50mm higher on side of tank, (before it was under the tank)
so my thoughts are its just. before all the waters wieght was pushing down on/in outlet, now it just sidewards pushing (and of course lost 50mm of water that is now below hieght of new outlet)

 

[Johntheo5]

Strange, wouldn't have thought the side outlet would make any difference or the lost 50mm, 0.05M, < 2 inches, also, if that electric shower has its own integral pump then even less effect, any possibility of air in the pipework after drain down, are there separate cold water outlets, one to the cold water users, and the other, to the HW cylinder?.

 

[goateater]

Did have an air lock but cleared that, CWS tank feeds down into hot water cylinder then on to the rest of cold water outlets (one pipe from CWS tank)

 

[terryplumb]

You should have two outlets from the cws ,one dedicated to the hot water cylinder ,and the other going to cold water outlets.
The outlet for the hot water cylinder should be higher than the other. In the event that the cws is starved of water supply ,the hot water would cease to flow first.
Have you closed off any gate valves ,which may now not be fully open ,causing lower flow ?
The pressure difference,based on your description of outlet position, would be negligible,if at all.
Is your shower instantaneous electric type? If so it should ideally be supplied with mains cold water.
It sounds like you have trapped air in the hot water distribution pipework.

 

[goateater]

Thanks, its only got 1 outlet as have all these local ex council houses, the CWS & F&E tanks overflow into the gutters (I've changed that in lads house)
I'll re-check how shower is fed,
Trapped Air = as this one pipe feeds Hot water cylinder and the cold water taps/toilet ect, (other than mains fed stuff) I'll redo the mains water attached to hot water pipe blow throw but this time flush toilet and have shower on (maybe the air is trapped along those parts of this one pipe

 

[Johntheo5]

Post the make/model of your shower to identify mains fed or from the CWST.
Could you attach a mains fed hose to the gravity cold water outlet somewhere and backflush?
Unlikely, but possible obstruction in the cold outlet at the tank or in the coupling but would require cistern full drain down to remove the pipe and check.

 

[dilalio]

Check the taps haven't collected any crap during the cistern change.

Remove and clean out any filters in them.

 

[goateater]

I'll try to get shower details later
wasn't too much muck in old CWS tank, but maybe some,
will check filters on any taps
Could you attach a mains fed hose to the gravity cold water outlet somewhere and backflush? possible to cut into pipework in loft and fit valves to allow "backflush" need to check other easy/quick stuff first

 

[goateater]

Showert is a Mira Sport don't know the size, its got 2 dials on the front

 

[Johntheo5]

Thats a mains supplied shower.

 

[goateater]

I'll check out shower next time i go over there, if it is fed via the mains could be the stop cock not open enough

 

[Johntheo5]

Or could be a blocked filter or the mains pressure may have been reduced, I had a 9.0kw Mira sport (upstairs) for 18 years and it required a dynamic pressure of 2.3bar to enable its flow stabilization valve to maintain a fairly steady flow if someone opened a cold tap. I t should give a flowrate of 8.0LPM with the temperature control turned fully anti clockwise to cold and will normally sit between 11 oclock position and 2 oclock winter/summer to give 3.9 to 5.2LPM to give a showering temp of 40C. (9.0kw model)