water level rose in CH expansion tank with system off and resolved when
 

I've just got back from hols to find the CH expansion warning pipe
dripping and algal?sp growth on the lean-to roof as a result so it had
obviously been dripping for some time. The boiler had been off while we
were away. I decided to leave investigating until today but magically
the dripping has stopped now that the boiler has been run a few times
for hot water. Why'd that happen?

--
dave @ stejonda

water level rose in CH expansion tank with system off and resolved when
 

dave @ stejonda wrote:
I've just got back from hols to find the CH expansion warning pipe
dripping and algal?sp growth on the lean-to roof as a result so it had
obviously been dripping for some time. The boiler had been off while
we were away. I decided to leave investigating until today but
magically the dripping has stopped now that the boiler has been run a
few times for hot water. Why'd that happen?

The ball-cock has been exercised and the washer is sealing better?

Worse case is your pimary coil in your hw cylinder has a small leak and this
is normally not noticed when you're drawing off hot water.

water level rose in CH expansion tank with system off and resolved when
 

In message , BillR
writes
dave @ stejonda wrote:
I've just got back from hols to find the CH expansion warning pipe
dripping and algal?sp growth on the lean-to roof as a result so it had
obviously been dripping for some time. The boiler had been off while
we were away. I decided to leave investigating until today but
magically the dripping has stopped now that the boiler has been run a
few times for hot water. Why'd that happen?

The ball-cock has been exercised and the washer is sealing better?

Worse case is your pimary coil in your hw cylinder has a small leak and this
is normally not noticed when you're drawing off hot water.

Ok thanks Bill, I'll bear those in mind

--
dave @ stejonda