What's most powerful, unvented or vented and pump? Mira Plat

[heatingeng]

http://cgi.ebay.co.uk/BALL-VALVE-CO...DIY_Materials_Plumbing_MJ&hash=item3caadb5b91

 

[heatingeng]

Do you know how old, or any other details of the supply pipe?

I'm presuming as the hw tank is so old, the property is too. And if it's a lead pipe, there's usually a possibility of getting it replaced (hence, upgraded, hopefully!) free.
Might be a good first step to see if it helps the smaller tanks keep up, and if nothing else, will only benefit any replacements.

House is probably 1970's. Cheaply built 2 bed terrace on a housing estate full of the same houses. Pipes are copper, I'm sure.

Flow at the downstairs kitchen tap (all on 15mm pipe) is 15.6 litres per minute. Pressure is 3.0 bar with no taps on. Drops by 1.5 bar when a tap is fully opened.

Most houses are 15mm and should not be a problem.

 

[Googlyhead]

Is there a way I can get the tanks to fill up quicker? At the moment they're filled by a floating valve but the flow is so slow it can't keep up at all. Any way I can get them to fill up quicker?

Clean them? Some have a strainer built-in, or they might simply be blocked with silt or solder. A DIY job would be to turn off the supply, and strip / clean them (perhaps fit a new washer, like a tap). If they're noticeably slow, I'm presuming there's a fault.
Older ones are rubber washer based.

 

[danyeates]

Ok, as a temp measure, I'll take it apart clean/replace as neccessary (I think I have a spare one anyway) and see how I get on. I think I'll look into replacing the tanks with just larger capacity versions at some point. I'm going off the idea of an unvented cylinder!