BANGING

TIRED

Wondering if anyone has any suggesstions for me.  We have baseboards for all 3 floors.  We have a real bad banging on the third floor sounds like someone is hiting the floor board with a metal bad in the middle of the night..When the heat first comes on it does not do this, it happens hours after when it comes back on.

We bled all three of the floors which we seem to have to do every year...

Please help us get a good night sleep.

Thanks in advance.

DanHolohan

Do you have zone valves?

Some zone valves will do that. 

Mark Eatherton

Could be steam flash...

If the system is operating under a marginal amount of pressure, AND the water from the boiler is extremely hot (say, around 200 degrees F) AND the pump is pumping towards the expansion tank, when the pump first turns on, the water in the top of the system is subjected to pressure below atmospheric, and BANG, steam flash...



or, could be that the zone valves are installed backwards, and when they are closing off BANG, the pipes jump and bang due to kinetic energy.



Has it ALWAYS done this, or is this something new?



How high is the system, and what is the water pressure at the boiler?



ME

Coany

a few things to check

check the pressure in the system.

there should be a guage on the boiler.

It should read12-18 pounds.



 if the pressure isn't low the operating control may be too high

  creating expansion noises



 lower the settings(both high and low) 10 or 20 degrees.



 and see if the noise is less



 also check to make sure the little arrow on the zone valve body

 for the third floor is pointing the right way.



if its wrong it'll make a bang when it opens or closes