This is the craziest thing. Last month I decided to tackle a few old leaks in the laundry. I removed the laundry sink and counter top, washer and dryer, and round under-counter hot water heater. Made the repairs, re-sheetrocked, painted and put it all back together. Nice weekend job and all looks goods. So I go around the house slightly opening faucets to bleed air and let everything purge and sputter. Once all the air is out I open the hot water to full on the spa tub and get a nice flow for like 3 seconds and then ...ssshhhhunckkk (sort of the sound) and the flow goes to half? My assumption is I have somehow broken lime sediment loose in the 10 year old water heater and that is clogging the lines at elbows and reducers.
So..after reading helpful ideas on this forum I decide to back flush the lines the following weekend. I do the dime in the aerator screen procedure, hot water tank discharge & supply off and flush from the spa (farthest faucet) thru the washing machine hose bib (closest to supply). And I do flush a little sediment out, but just grains...nothing big. And nothing helps. I get full flow for 3 seconds and then ...ssshhhhunckkk and half flow. I spend a few hours back flushing from each faucet and then opening that faucet first and get the same result. I get flow full for 3 seconds and then the sound and half flow. Once I get half flow at the test faucet...all faucets flow at half volume. And it is literally half flow ( cold 7 gpm, hot 3.7 gpm)
Now I am at a loss. So the next weekend I decide to replace the 11 year old water heater. We have hard well water here so I am thinking maybe, just maybe, there is like a chunk of lime that is somehow flapping up against the dip tube pick up. I justify in my mind that the old tank was showing a little corrosion anyway so it's not a bad thing. Nope sport fans....same result. So I go golfing a few weekends and ignore it.
This was the first cool weekend in South Georgia and half flow of hot water in the shower was just not getting it - so I decided to have another go at it. The CPVC water lines are accessible in the attic having been replaced decades ago when the copper piping in the slab rotted away. At the farthest end of the house I cut in a Tee and with adapters made a connection to a new pump up sprayer. I pumped a solution of Lime remover into the system and opened each faucet until solution ran. After a 2 hour soak I flushed the lines and - got the same results.
Oh boy! It’s time to start cutting line out. I start crawling thru the attic looking for suspects. The very first fitting I uncover is a reducer on the main house supply 20 feet from the hot water tank. I cut it out and out falls a small blue glass marble. I really don’t get it. Where could this marble come from? Were marbles ever used in a check value on a tank? I am lost, but with the marble removed the system works fine.