boiler cleaning

smc

I have a customer with a cast iron hot water boiler he says is less than 5 years old making knocking noise. Any sugestions on cleaning? I had him turn water supply off the pressure has not dropped dont think there is a leak
on well water. Just follow manufacspec?

Big Ed_4

What does the boiler temperature......

....rise to after the burner shuts off. Knocking in a hot water boiler mean to me that it's breaking steam ....

Mark Custis

Thanks Big Ed

I thought that too, or mild soap and water.