Poor Hot Water Pressure - little flow

[Brimap]

Hi, Recently had issues with our old bolier which at present I'm unable to replace - Cost mainly. Last winter the circulation pump based next to the hot water tank in the back bedroom had to be replaced to enable the heating system to work, which was fine and we had both hot radiators and hot water. Over the summer the hot water was fine but recently since this winter the pressure had been reducing in the hot water until we are the point now the flow from the bath tap/sink tap runs for about a minute then stops. The hot water in the kitchen runs for about 2 minutes then again the flow reduces and stops. If you turn off the taps the pressure builds up and the the same happens again. I have tried fluishing the system using the pressure from the cold supply to run through the hot water and of course have a good flow rate in the kitchn and bathroom, which seemed to cleared the issue for a day or so then we are back to square one. I can't find anything blocking the flow of water from the storgae tank in the loft - thoughts and suggestions greatloy appreciated. !!!:sweatdrop:

 

[Simon F]

Hello Brimap,
does sound like a blockage/scale build up in the hot pipes or the cold feed to the hot cylinder,
possibly even a restriction in the hot overflow/vent pipe.

 

[tipintim]

Is your cold water tank filling up quick enough, i.e is the ball valve blocked?

Are all valves open fully?

Gate valve been turned off, re opened, yet snapped and partially shut?

 

[zzzjim]

Is your cold water tank filling up quick enough, i.e is the ball valve blocked?

I like the sound of this , as the pressure drops off .

Visually check tank is not draining faster than its filling .

 

[jtsplumbing]

If in hard water area, could have scale build up on fitting on top of cylinder, had this loads of times when I lived in Barkshire.

 

[aqualogic7]

have a look at valves on pipework in roof space if they are stopcocks and in a upright position then there is an air lock loosen nut on stopcock and turn so laying down this should clear airlock

 

[Brimap]

Thanks to everyone who has posted a reply on this subject. Will try and answer all in one go:

Differently in hard water area - so possible the scale could have built up - if it has how do we remove this. !!

Filing to the storage tank is working fine - not draining off faster than filing.

None of the values have been switched off except for the secondary mains fill stopcock in the loft- which has statrted to drip - had tured it off to check the tank for any bits/items that may have been blocking the flow of water.

Airlock - Stopcock in roof is in upright postition but not confident enough to do as you suggest in case the whole things goes wrong as these have been on for quite a few years - plus the mains stopcock is a difficult postition in the kitchen and i have been in the house for 10 years and never swithched it off. So it will more and likely be stuck and if i force it i could be using the kitchen as a swiming pool instead !

If we look a blockage could it be from the storage tank to the cylinder hence reducing the flow - if something has got into these pipework any suggections how we could clear it !

 

[jtsplumbing]

Poss that cylinder has a lot of scale in bottom, you need to drain tank and remove fittings at top and where cold water go`s in bottom, but be careful, iv`e had them snap off, drain roof tank & Cylinder replace old gate valve with full-flow leaver valve, worst case you may have to replace cylinder.