Should filling bath use all hot and cold water?

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usrbin

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Would welcome any advice on this - probably nothing, but anxious to understand if it's normal or not.

We have a corner bath - not huge, but possibly bigger than a straight tub. We can just about fill it with a mix of hot and cold water before the tap just dries up, i.e. the water stops coming. I can understand that the hot water might be all used, but would have thought that, having turned off the hot and trying to "top up" with cold, the system should be able to, I dunno, draw from the mains water supply even if the tank in the attic is empty... making any sense?

I know almost nothing about plumbing but I can say that we have one of those systems with an expansion vessel, I think they're called - red globe beside the OFCH boiler in the kitchen. Only one tank in the attic.

Thanks in advance for any wisdom/opinions.
 
Sounds like your hot water storage vessel (the insulated copper tank) and your cold water storage tank (in the attic) are too small for the size of your corner bath. When you run the hot tap the copper cylinder is being drained and this in turn draws cold water from the tank which refills the cylinder; when you run hot and cold together the cold tank can drain very quickly and when both hot and cold tanks are simultaneously refilling you will have problems trying to draw further water off at another tap.
 
For the bath, both hot and cold a feed from the tank in the attic. The hot water cylinder will always remain full of water, but uses water from the cold tank to fill it/push hot water out of it. Your cold tank is running out of water so the problem is a combination of:

A) Not filling fast enough.
B) No or low mains water pressure.
C) Tank too small.

A and B are interconnected, chances are B is the problem, but fixing C is probably the easiest/cheapest way of fixing/working around the problem.

Towger
 
Guys, thanks a million, very useful advice and information, much appreciated. I'll see about getting a larger cold water tank put in I think, seems like the easiest workaround.
 
Hi UsrBin,

Instead of replacing the existing tank, if you've the room, you might install your new attic header tank "in series" with the old one.

ALERT.
 
Brilliant, of course, thanks Alert, that's what we'll do, much easier, thanks!
 
If fitting another tank in series it would be important that there be adequate flow through through both tanks to prevent stagnation, again a good plumber will advise.
 
Carpenter, good point, as ever, I will watch out for that (when I find a good plumber...)
 
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