[haroldw]

I have a lawn sprinkler system 3 zones that in summer run in total approximately 1 hour. The system is scheduled to run at 5:00 a.m. When I go to shower after the system has water or use any hot water supply the water runs slowly for a few seconds then I hear a pop sound and then it runs normal. It’s as if there’s an air bubble in the line. This only happens after using the lawn sprinklers no other water source. I’ve already installed a an anti-pipe knock devise in the sprinkler line and a pressure regulator in the water main line set at 60-65 lbs. Anyone know what’s causing the problem with the hot water line?

Thanks,
Harold

[massplumber2008]

Hi Harold

With what you have presented I am thinking you could have an issue with the HEAT TRAP NIPPLE installed at most water heaters nowadays.

Check your heater nipples and see if they look anything like in my pictures below (look for the indented line around the nipple).

If you have these nipples it is possible that the heat trap ball is getting hung up in the nipple. If this is the case you just need to remove the heat trap nipple(s) and install regular dielectric nipples at the heater.

You or a plumber can install a heat trap by installing a simple UTURN in the hot water pipe... can discuss more if you want, OK?

Mark

[speedball1]

I think Mark nailed it! Check the nipples, (see image) and either replace with a 3/4 X 3" brass nipple or build your own heat trap.(see image) Good luck, Tom