pasadena_commut
Well-Known Member
Last weekend I was trying to figure out the cold/hot water imbalance in our tub. (Less hot water flow than cold. Determined that there is no restriction on the hot side in the 3 handle set at the tub by threading a long zip tie in from the hot side until it was visible in the center, with the hot and diverter stems out. Problem is likely either a restriction further back in the hot water pipes or in the water heater itself, possibly at the hot water nipple.) Anyway, while I was futzing around with this, with the water shut off at the heater, and the hot water pipes drained, the heater came on. It bumps a little bit now because it is due for (yet another) sediment clean out. However, these were not little bumps, it was much much louder. Turned the heater off until the the stems were all back in and the water turned back on, then relit it. It was back to normal volume bumps.
So why the volume difference? Anybody know the answer?
I'm thinking either acoustic amplification from the empty hot water pipe or a pressure effect at the bottom of the tank. In the louder state the pressure in the hot water pipes was zero, so the pressure at the bottom of the tank was whatever corresponded to that much standing water, maybe 2 psi or so, instead of the usual 80 psi.
So why the volume difference? Anybody know the answer?
I'm thinking either acoustic amplification from the empty hot water pipe or a pressure effect at the bottom of the tank. In the louder state the pressure in the hot water pipes was zero, so the pressure at the bottom of the tank was whatever corresponded to that much standing water, maybe 2 psi or so, instead of the usual 80 psi.
