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4" Cast Iron usage with 1.6 flush toliet

We have a toiiet that is dated 1950 and still works but still flushes a 5 gallon amount. I would like to replace with a 1.6 flush using exiting 4" Cast Iron drain. There is about 2 to 3 feet of horizontal pipe. I was told by a person at the local plumbing store that I should not use the 1.6 flush because there is a small amount of water to wash the solids in the horizontal area. He said in due time it would cause problems due to backup.
Can you help on this matter?
Thanks in advance.

Re: 4" Cast Iron usage with 1.6 flush toliet

There installed on cast iron all the time. All though cast iron is more likely to have stoppages then say plastic. That being said I would not let that stop me from installing a 1.6 toilet.


Re: 4" Cast Iron usage with 1.6 flush toliet

Before you purchase the new toilet, measure how far away from the back wall the bolts holding down the existing toilet are. The standard measurement nowadays is 12 inches; some of the old toilets were 15 inches or more. This means your new toilet could end up sitting 3 or so inches away from the wall. If the measurement is less than 12 inches, the new toilet won't fit at all.

You can get modern toilets for different measurements, but they are special-order items, and the selection may be limited.

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