DIY Doctor

Hot water intermittently not responsive in 1 tap and 1 shower

Postby scg1889 » Sun Dec 13, 2020 7:45 pm


Wonder if you could help me try and diagnose a problem. I've got a traditional gravity fed hot water / heating set up.

Initially the hot water from the kitchen tap would pause about 2 seconds before it flowed but this only happened about once every 4 weeks. As time's gone by this has become more regular - pretty much daily now and the time has increased up to about 10 to 15 seconds. Over the last couple of months this has started to happen with the en suite shower, this can be quite a few days apart but just now had no response for 30 seconds. switched it off and back on and finally came through after about another 30 seconds. Our other shower and bath have had no problems.

I have a new cartridge ready to fit in the tap but i'm thinking with the en suite shower it's a more central problem. Cold water is fine in every room and hot water is fine everywhere apart from kitchen tap and en suite shower (though the basin hot water tap in the en suite has never had an issue)

I've had a look in both my tanks in the loft. The smaller one which i understand is for central heating expansion and shouldn't affect hot water (please correct me if i'm wrong!) has quite a lot of what i'd call 'silt' in it towards the bottom. The larger tank has some of this silt in - but much less - and the pipes that come out of here are high up so would i be right in thinking that's a red herring - or would that silt potentially rise up with changes in water level?

I've attached pictures.

Any ideas welcome, I don't want to pay for the expense of attempted solutions if I'm barking up the wrong tree with any theories and i've had an absolute disaster in a previous house with a powerflush. Do you think it's worth trying a new cartridge in the kitchen tap or does the fact the shower struggles too rule that out.

Happy for any thoughts even if it only rules out one small thing
large tank
small tank
Pipes (2).jpg
pipes on large tank
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Simply Build It

Postby stoneyboy » Tue Dec 15, 2020 10:25 pm

Hi scg1889
There’s a fair chance that non-return valves are fitted to the tap and shower which have issues. If you can find them try cleaning them.
Regards S
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