I have just bought an old 3 storey house. It has toilets on the second and
third floors. The toilet on the third floor works fine. The one on the
second also flushes with no problem but the water level in the toilet bowl
slowly drops over a couple of hours. Both toilets flush into the main
vertical stack in the house. I have tried flushing the second floor toilet,
letting it fill to its normal level and then flushing the third floor one to
see if it is causing syphoning action but it has no effect on the second
floor toilet level. Other than this there appear to be no other weird
plumbing problems. The waste plumbing is ABS. Any ideas?
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