Ok, so now I’m stumped.
I have a house with a 1” PVC 4 zone sprinkler system. The supply line to the house is 1” and comes from the meter at the street, then goes into the crawlspace and then after about 30 ft it pops up into the garage where there is a single back check valve and the expansion tank for the water heater.
The sprinklers are connected to the supply at the meter and then go to double back check valve.
Every time I turn on one of the sprinkler zones I get crazy violent water hammer on the main line in the crawlspace. This is a few seconds after the zone valve is turned on.. (no issue when valve turns off). As the valve is filling the pipes in the yard the hammering starts and always stops when the first head of the zone pops up..
We just replaced the water heater and the expansion tank had failed so we put in a new one and set the pressure in the expansion tank to match the water pressure.
I suspect the issue is related to the expansion tank as I never had this problem before we replaced the tank. Maybe it allows the pressure to fluctuate in a way that sets up some kind of resonance on the supply line into the house.
Now for the issue.. since the water for the sprinklers connects to the meter and the main feed to the house connects at the meter, I put the water hammer arrestor in the valve box with the back flow preventer. But it didn’t do a thing it is on the sprinkler side of the backflow valve.. The water hammer effect still goes nuts when one zone turns on..
I guess my next step is to try to crawl under the house and put the arrestor on the pipe that is hammering. Didn’t want to start here because sweating copper under the house is not as easy. Any theories on what is going on?
I have a house with a 1” PVC 4 zone sprinkler system. The supply line to the house is 1” and comes from the meter at the street, then goes into the crawlspace and then after about 30 ft it pops up into the garage where there is a single back check valve and the expansion tank for the water heater.
The sprinklers are connected to the supply at the meter and then go to double back check valve.
Every time I turn on one of the sprinkler zones I get crazy violent water hammer on the main line in the crawlspace. This is a few seconds after the zone valve is turned on.. (no issue when valve turns off). As the valve is filling the pipes in the yard the hammering starts and always stops when the first head of the zone pops up..
We just replaced the water heater and the expansion tank had failed so we put in a new one and set the pressure in the expansion tank to match the water pressure.
I suspect the issue is related to the expansion tank as I never had this problem before we replaced the tank. Maybe it allows the pressure to fluctuate in a way that sets up some kind of resonance on the supply line into the house.
Now for the issue.. since the water for the sprinklers connects to the meter and the main feed to the house connects at the meter, I put the water hammer arrestor in the valve box with the back flow preventer. But it didn’t do a thing it is on the sprinkler side of the backflow valve.. The water hammer effect still goes nuts when one zone turns on..
I guess my next step is to try to crawl under the house and put the arrestor on the pipe that is hammering. Didn’t want to start here because sweating copper under the house is not as easy. Any theories on what is going on?
