Hot water pressure drop

[myhippocket]

Hi folks,

Recently I started noticing a pressure drop in the hot water coming from the kitchen tap in our house. What happens is the hot water runs at normal pressure for about 5-10 seconds, them drops by about 50%. It is a single lever tap and the cold water is not affected at all by the pressure drop. Also, none of the other taps in the house have this problem with the hot water pressure dropping. Which leads me to the conclusion that either I have somehow got something in the hot water line going to the kitchen sink (the system has not been opened up), or there is something wrong with the tap itself. Anyone have any ideas as to what could be going on? I have not yet pulled the tap apart. Thanks in advance.

Hip

 

[gas4you]

Check the cold outlet on your cold storage tank in your loft is not blocked.

 

[chrishutt]

Hip is posting from Canada so may not understand or be familiar with UK terminology. Hip, we would need to know what sort of hot water system you have.

 

[myhippocket]

Hi guys,
I have a 40 gallon natural gas water heater. One cold line in to the tank. One hot line out that runs to a plumbing manifold. All the hot water lines (plastic) in the house come from the manifold and run separately to each faucet. So the hot water line to the kitchen sink is run from the manifold directly to the faucet. Hope that helps.

 

[gigz]

My guess is the washer is expanding as it gets hot and narrowing the outlet from the tap. When the pressure reduces is the water coming out hot or cold ?

 

[myhippocket]

The water is hot when it come out. It runs hot for about 5 - 10 seconds, then the pressure suddenly drops to about 50% of that. It does not drop gradually.