Low flow from hot tap

[colshaws]

Hi all, I have just popped over from the electricians forum hoping to get some help. I have a swan neck style mixer tap on a kitchen sink on a gravity fed system that was fitted about 6 months ago. The cold water flow is fine but the hot water has slowed down by about half. I have removed the swan neck from the body and this seems to be free of any obstructions, the inline service valve under the sink (screw driver slot type) is in the fully open position. Does anyone have any ideas and if I were to connect a pressure guage to the hot supply what pressure should I expect to see. There are no other taps down stairs so I cant compare the pressure to confirm wether its the tap or a supply problem.
Many thanks.

 

[Puddle]

Did the hot water flow decrease once you replaced tap or slowly since,the cold is from mains so will be ok,if problem since replacing tap,probably put a high pressure tap in,if slowed down since ,check airiator at end of spout if one fitted,if not,may have a partial air lock in hot pipework,try placing folder rubber glove over spout end,turn hot on and then cold and see if bb forcing some mains cold back up hot pipework you can clear it

ps be prepared to get wet :greedy:

pps If hot water from open vented cylinder,pressure will depend on height of tank supplying cylinder,if you tell us hight of tank from tap,we can tell you pressure you should have

 

[colshaws]

Thanks for the reply, I didnt fit the tap so dont know if its a low or high pressure tap, its in an elderly relatives house and I have been "voluntered" to try and sort the problem.I have checked the airator and seems clear.The hot water flow has decreased slowly since fitting, the hot water tank is in the bedroom upstairs, i wanted to measure the pressure to eliminate the tap and then be able to hand over the job to a plumber.

 

[stevetheplumber]

try taking the tap body out and stripping it down and regrease
taps today are crap bring back the rising spindle

 

[Best]

You don't need to check the pressure. As it had better flow before, then check the end of spout as puddle has said, if ok then remove the hot works. If the washer ok then take works apart & use silicone grease on them. Should work, at least for a time. Often it is bottom ' o' ring worn, maybe only a little, that's the problem. Old taps years ago weren't made like this. If you aren't sure, why not swap the works (if you could be bothered) to see if hot then has better flow?

 

[REDSAW]

air lock?.

 

[AWheating]

changing the ballofix for a full bore isolator could help increase flow rate...... tho this wont help if tap has a restriction.

 

[Best]

Yes, 6 months is not old for taps to fail, even by the standard of new taps. Still could be works though, as some new ones aren't greased. If it is ceramic disc, quarter turn works then they shouldnt suddenly reduce flow. If it is airlock, then holding hand over end of spout & turning hot + cold on, might work, but a lot of necks of mixers have separate flows through them so you might have to remove neck first. It could be held in with a screw at back of mixer or just needs turned to one side & lifted up. Then hold hand over mixer. Don't drop screw down waste!