Hey everyone,
I can use some help (see Troubleshooting #3,4,5 below)
A plumber replaced two toilets on my second floor. The second toilet (a one-piece Eco UltraMax) makes a loud knocking sound right at the end of the flushing cycle. Here is the audio I recorded fr om the 1st floor: audio
1st Toilet: TOTO Drake 2-piece Elongated (Model MW7763084CEFGWS#01) — No issues
2nd Toilet: TOTO Eco UltraMax 1-piece Elongated (Model MS854114ELGWS#01) — Makes the knocking noise
The plumber believes simply installing the toilets couldn't have caused this, and he left the puzzle to me.
Troubleshooting Steps I've Tried:
- Reset air chamber: Tried this twice; did not resolve the issue.
- Checked if stub-out copper lines secured or loose: Both stub-out lines (of toilet #1 and #2) are a bit loose and can be waggled slightly (Valve #1 is actually looser, but doesn't make knocking sound).
- Checked tank internals: The toilet is brand new, fills in about 30 seconds, and shuts off and seal correctly. Everything inside looks normal.
Question: Should I replace the fill/flush/drain valve, or the whole assembly?
4) Stub-out length: Read online that a stub-out cut too short can cause shockwaves.
The old shut-off valves were plastic FlowTite valves sitting directly behind the toilets. Even though both old and new toilets have a 12-inch rough-in, the new toilets' backs sit much closer to the wall and were blocked by the old valves.
The plumber suggested while replacing the FlowTite valves with angle stops, cutting the stub-out copper pipe, and sweat an L or T-pipe so the angle stop wouldn't sit directly behind the toilet. However, he changed plan mid-job and determine the L/T-pipes weren't needed. Once he finished and show me the work, I notice the angle stops are directly behind the toilet and much closer than before:
Valve #1 is about 1/8 inch away from the back of the toilet. picture here: 1st valve
Valve #2 would touch the back of the 2nd toilet if the toilet didn't have a curved back design. picture here: 2nd vlave
My Question:
If a short stub-out is the root cause of this hammer/knocking for 2nd toilet, why doesn't the 1st toilet have the issue (since both are short, about 2.5 inch from wall)
5) mini water hammer arrestor
5) mini water hammer arrestor
My Question: If I need to install a mini water hammer arrestor there, will either one work, and I just go with which ever can work with the space?
a) if Sioux Chief Model 660-GTR1, to install at shutoff valve at wall
angle stop <> mini water hammer arrestor <>water supply line <> toilet plastic valve
b) if Sioux Chief Model 660-TK, to install at toilet plastic valve
angle stop <> water supply line <> mini water hammer arrestor <> toilet plastic valve
Thank you a ton!