Last year our sprinklers worked fine. This Summer when the sprinklers turn on or the zones change, the house shakes and it sounds like a train is going through our house. We have had 2 plumbers, 2 sprinklers guys and someone from the water dept come and no one can figure out what it is. The noise doesn't happen when we use the water in the house. A plumber said the expansion tank is full but the boiler company tested it and said it is not. The plumber put in 1 T bar and now a 2nd one and the problem continues. We were told that the plumber needs to move the connection between the water pipe that comes into the house and the pipe that goes to the sprinkler line above the pressure regulator. Will this fix the problem? What is the cause of this?

Please explain a little more about the noise you hear. Is it a chattering noise? A banging noise? A squeal or howl?
What expansion tank? On the water heater? On the water service? If the tank has a snifter valve on top to recharge it why not test it for yourself? Open the snifter valve and if water comes out of it the tank's faulty.
"We were told that the plumber needs to move the connection between the water pipe that comes into the house and the pipe that goes to the sprinkler line above the pressure regulator."
You don't have your sprinklers on a separate meter? Are they getting street pressure at the present time? What is the street pressure before the PRV valve enters the house? Regards, Tom

Please explain a little more about the noise you hear. Is it a chattering noise? A banging noise? A squeal or howl?
What expansion tank? On the water heater? On the water service? If the tank has a snifter valve on top to recharge it why not test it for yourself? Open the snifter valve and if water comes out of it the tank's faulty.
"We were told that the plumber needs to move the connection between the water pipe that comes into the house and the pipe that goes to the sprinkler line above the pressure regulator."
You don't have your sprinklers on a separate meter? Are they getting street pressure at the present time? What is the street pressure before the PRV valve enters the house? Regards, Tom

It's a banging noise.
The expansion tank is on the water heater. The oil co. tested it at 100 psi. They said it was empty.
The sprinklers are not on a sepatate meter.
When the water district came to test the pressure, they also registered 100 psi.

The sprinkler people came to install a pressure regulator on the outside pipe leading into the house to the main. This did not accomplish anything. I'm waiting for the plumber to come back and move the tee from below the pressure regulator to above it. This way the pressure should be reduced before it goes to the sprinkler pipe. The plumber was asked to do this originally, but decided to install a hammer on the pipe. This has not worked

In this business I've learned not to take anyone's word for anything. Did you pop the snifter valve and see if any water came out of the expansion tank? Let me know. Tom