When the steam hits colder piping it turns to condensate and the steam hitting the water (condensate) produces hydraulic shock waves.
Most likely.
Water hammering on any quick closing valves
choir members in your pipes
I don't even know what a recirculating pump does but when fast moving water hits a corner or elbow it has a force that can move the pipe. Most likely the pipes need a bit more tie downs. Hopefully the pipes aren't in the walls. Get someone to cut the water on and you go hunt the rattle.
Do your pipes freeze .
Pipes rattle when water is turned off due to a phenomenon called water hammer. This happens when the sudden stop of water flow creates a pressure surge that causes the pipes to vibrate and make noise.
High water pressure could be the reason for pipes to rattle when you turn on the outside sprinklers. You may need to have a reducer valve installed.
Singing water pipes can be caused by air that is trapped in the pipes. The air can cause a whistling or singing sound, or it can cause the pipes to knock or rattle.
Water Hammer.
Most likely.
Water hammering on any quick closing valves
I'm not familiar with rumbling in pipes, but the clanking of pipes when the heat starts up is a result of the pipes expanding because of the heat. Heat causes the metal to expand slightly, and the joints creak and clank when the heat makes its way through the pipes.
Hammering pipes is the result of inertia when moving water causes the pipes to move when a valve is suddenly turned off. Use an anti-hammer device. You can purchase one at most home centers.
choir members in your pipes
Heat tape is used to prevent pipes from freezing in cold weather by providing a controlled amount of heat to the pipes. It wraps around the pipes and is usually self-regulating to ensure that the pipes stay at a safe temperature.
Pipes can vibrate or rattle when hot water is flowing due to expansion of the pipes from the heat, causing them to rub against surrounding surfaces. This can be exacerbated if the pipes are not securely fastened in place. Additionally, air bubbles trapped in the water lines can create turbulence and vibration as water flows through the pipes.
yes, as they heat up or cool down they groan