Toilet tank overflow NO CLOG

Hello:
I need some help with this. I have two Gerber toilets in one of my rental properties which I purchased and installed in 2004. Last week a tenant called and said she went to the bathroom in the middle of the night, went back to sleep and was awakened by the ceiling in the living room falling down and water all over the living room (lower level) and bathroom (upper level). She claimed that, after she flushed, the fill valve malfunctioned and kept running, but the toilet was not clogged. Thinking this was impossible, I went to the property to inspect the damage. I held the float down, and, believe it or not, the toilet tank continued to fill, since the overflow pipe could not drain the water as fast as the fill valve let in into the tank. I checked the other toilet and the same thing occurred. Has anyone ever heard of this? It seems to me that this is a design flaw, but Gerber denies it. I have repaired the ceiling, and am thinking of replacing the tanks on both of these, but leaving the elongated bowls. Again, has anyone else had this problem?

the overflow pipe could not drain the water as fast as the fill valve let in into the tank.

Click to expand...

I have not heard of that.
You can buy a fill valve with adjustable fill rate though.
Korky makes a 528MP, MaxPerformance. It allows you to change the refill rate.

The fill valve should have been adjusted so that the refill shut off when the water reached 1/2" below the top of the overflow.

WOW! That is a poor design where the fill rate is faster than the overflow drain.

Decades ago when I lived in rentals, I would reduce the fill rate by partially closing the angle stop. Mind you, I did that so as not to get scalded in the shower when roomies would flush the toilet.

Don't waste money on a new tank.

I would swap the flush valve on the toilets with a Korky 4030 flush valve (if it's a two-inch flush hole in the porcelain; if you have a 3" hole in the porcelain, use the 5030, which is newer and probably easier to find online than locally). For the 4030 (2"): http://www.lowes.com/pd_125469-868-4030PK_0__?productId=3158681&Ntt=korky&pl=1&currentURL=?Ntt=korky&facetInfo=

It's a simple flapper design that will fit in your toilet, using the world's-most-used-flapper, Korky. More importantly for you, the 4030 and 5030 have a wider overflow riser than most, so in a true runaway-fill-valve situation, they can run as much water out of the tank as runs into the tank. When I rehabbed a number of oid toilets, I started using this kit just because it's a quality flush valve, comes with decent hardware, has a twist-to-lock-extendable overflow riser so you don't have to cut it, and seemed well-made. As completely-runaway fill valves aren't all that common, I thought the wider overflow riser was merely nice to have. Your story brings home that it's probably very-nice-to-have.

You are also going to need to swap out that fill valve. Use a Korky 528 MaxPerformance, available at Lowe's and everywhere else (except HD). Reliable and easy to fix. It's part 528MP (528MPK at Lowe's). http://www.lowes.com/pd_336988-868-528MPK_0__?Ntt=528mpk&UserSearch=528mpk&productId=3284948&rpp=32

Here's a video from Korky showing the operation of the wider overflow riser:


Of course, if you want a real workhorse toilet that will last a long time, make your tenants happy because it flushes so well, and uses readily-available, inexpensive repair parts, you could chuck those Gerbers and get the basic, original Toto Drake for about $220 each street price. CST744S or CST744E. The S is 1.6gpf and the E is 1.28 gpf and eligible for Watersense rebates where applicable. See here to find out more: http://www.epa.gov/watersense/rebate_finder_saving_money_water.html