About 6 months ago, I converted from forced hot air to hydronic baseboard. Recently, a loud banging occurs once in a while from the pipes. After close examination in the basement, I saw the cold water pipes vibrate and bang. At first I heard a tick, tick, tick that got faster followed by a quick burst of loud bangs with vibrations in the cold pipes. This all occurs WITHOUT any water running. When the plumber did the conversion, he installed an Amtrol Therm-X-Trol expansion tank on the cold water pipe about 45 feet from where the main enters the basement. Please help!!!! I want to finish a portion of the basement but I want to get this problem solved first.
Thanks,
Jack

 

I don' know how closely you have checked, but the sounds you described are exactly what you would get as the heating system sends hot water through a cold copper pipe. Expansion through hangers and against wood. The same could happen with domestic hot water pipes but not just cold water pipes. The heating system noise would not require you to be using water to hear it but the domestic water pipes would need a water draw to get the hot water flowing through. See if it coincides with a call for heat.

 

All of the copper pipes have armor-flex (foam insulation) on them where all the hangers come in contact, there is no copper to copper contact. In addition, where the copper pokes through the upstairs floor (1 3/4" holes) for the baseboard also has armor-flex covering the pipe where it goes through the hole. The one time I witnessed the banging, it was right after the call for heat but it was definately the cold water pipe that vibrated. Should there be an expansion tank on the cold supply where the main enters the basement????
Thanks,
Jack

 

No on the tank. The tank you already have will accept expansion from the entire water system. The pipe insulation is a good idea and probably eliminated 99.5% of the annoying noises that you could have. What is the hi limit and low limit set at on your boiler? Does your boiler have a hot water coil in it? If not what is your source for domestic hot water?

 

I will have to look at what the high and low limits are set to then I will re-post. I have a Weil McLain indirect 40 gal storage tank for domestic hot water.

 

Are the heating system pipes between the boiler and the indirect tank insulated? Or could it be them moving and banging?

Water temps are less likely to cause the noise if you are using an indirect water heater.