I'll Just Give Your Pump A Tweak.
"Well that was money for old rope. There's nothing wrong with the system," he announced. "I'll just tweak your pump a bit."
He reduced the speed of the pump and said he reckoned that the pump was turning too fast and causing the hot water to find the easiest way round the system, in this case up the expansion pipe and into the header tank and then out of the overflow pipe.
Nice job old son. You'll be pleased to know that the overflow is running again today so you'll have to tweak something else. I hope that next time they send someone who knows what he's tweaking.
The next visit is tomorrow morning. The plumber with the plunger comes from Green's Home Repair in the Phoenix East Valley area who had nothing to do with the installation or repair. If you live in the Phoenix East Valley area and you need a plumber with a plunger, a click on the graphic will take you to their site. Unfortunately I live in Bogsville.