Why is hot water tap losing pressure in the evening?

[RrogerD]

The hot tap at the kitchen sink, fed from the combi adjacent, is fine in the morning but then as the day progresses it reduces in pressure until the evening when I am getting nothing more than a dribble. The cold is fine.

The other taps around the house are all fine also.

Any ideas?

I replaced the washer last week as it wasn't turning off fully. Could this have anything to do with it? It is a screw-fixed washer.

Could it be that the washer is expanding with the constant heat and gets bigger and bigger as the day goes on until blocking off the flow altogether?

Seems odd.

 

[oldbutnotdead]

Unlikely. More likely there are bits of old washer or other rubbish in the pipe leading up to the tap- water pressure pushes them up towards the tap seat and reduces available bore

 

[RrogerD]

Unlikely. More likely there are bits of old washer or other rubbish in the pipe leading up to the tap- water pressure pushes them up towards the tap seat and reduces available bore

Okey doke, thanks.
I'll take the tap apart again in the morning and have a swish around and a clean-out and see if it helps.
Cheers

 

[oldbutnotdead]

If the tap is connected to pipework via a flexi there might be debris getting pushed up the flexi (their internal diameter can be very small)....may end up having to take the flexi off, run the open pipe into a bucket for a while, reverse-flush the flexi (or blow it through with an airline)

 

[Madrab]

When the flow start to reduce, try pulling the tap head upwards, does that then increase the flow? If so then the valve needs to be stripped down and lubricated (use a silicone grease, not a petroleum based lubricant)

 

[spiidey]

Ok tried again and when step 4 complete (Lowest hot water tap back off; cold water infill to cylinder on), can hear what sounds like air quite loud from hot water cylinder.

Not sure what to do next.

Help!!!

 

[terryplumb]

Ok tried again and when step 4 complete (Lowest hot water tap back off; cold water infill to cylinder on), can hear what sounds like air quite loud from hot water cylinder.

Not sure what to do

Help!!!

Confused !!!

 

[dilalio]

Confused !!!

@spiidey posted in wrong thread.