Noise from Hotwater & low water level in toilet

[chris71]

Hi

I have a very loud sound coming from the hot water it sounds like a fog horn. It seems to start when someone is running a hot tap and goes on for about 20 secondsa before going quiet. I have tried to trace it but by the time I get up to where I think its coming from the noise stops.

Could it just be a pressure build up in the system or something else thats simple.

The other problem I have is with a toilet. When the toilet is flushed the bowl fills up while its flushing, but then the water level starts to drop and goes really low until there is only a small amount of water in the bowl. What is causing the water to drain and how can I solve it.

Any help on either or both problems much appreciated.

 

[kevplumb]

1 ball valve in hot water feed tank
2 partial blockage

 

[brumylad]

has the WC pan always emptied like this ?

if yes then it may be a siphonic type pan and is designed to flush like this.
If no then as Kev suggests, you had better get out your drain rods.