Long time reader, first time poster. Anyways, here's the deal. I have a building that I take care of, they have 2 air cooled chillers and a 1.5M Btu boiler. They called in a couple weeks ago and said the pressure relief valve on the boiler was spewing water. I went over there and with the pump off had standing water pressure of around 70psi, with the pressure relief being set to 60psi. We have in house plumbers, so I called them, they said the incoming regulator failed and replaced the pressure regulating valve and I think did some toilet repairs. They set the regulator to 30 psi and rolled out. Well ever since then, the customer has had complaints of hearing water rushing through the boiler loop. Ive been over a couple times since then to play around with the system and see if I could get it to quit and noticed a couple issues. For one, the pressure at the pump varies excessively, like a lot. The differential across the pump is around 30 to 35 psi which seemed a lot higher than usual. And the inlet water to the pump can spike up to 60-70 psi causing the supply side of the pump to almost peg out the gage at 100 psi. However, when the pump is running at such high pressure the noise inside the loop quits. It sounds like you can hear water rushing through the loop when the pressure is lower. Ive tried dialing the PRV down and bleeding air from the loop, its never had air in it when I open the ball valves, and the lower the pressure the louder the noise seems to be. I dont want to turn them away to another contractor because they're a great customer. But I honestly have no idea where to go from here. Sorry the post is so long, but I figured I should just lay everything on the table. Any input would be much appreciated.
