Replacing rusted drum trap with pvc ptrap.

[jsarin1]

I'm installing a new tub and removing an old drum trap. I'll be replacing the galvanized piping with 2in. PVC/P-Trap using a shielded Fernco between the new and old work.

The pipe to the main drain line is higher than the drum trap, about 2" below the plywood floor above. The bottom of the drum trap was 6" below, to clear a joist. The original piping had (2) 90's and a short vertical run to make up the height difference.

Would it be ok to use (2) 45's after the P Trap to make up this height difference? From what I've read, vertical bends are not good in drains, but I don't know how else to do it. Unless I cut a 2" hole in the joist... Photo attached.

 

[Reach4]

The trap arm-- the pipe between the output of the U of the trap and the vent-- must not go up. It must slope downward.

 

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[Jeff H Young]

the p traps are almost never too high on a tub I dont see why you would be in a jam

 

[jsarin1]

The ptrap is lower than the pipe that leads to the main sewer line by six inches. This is because of how they had positioned the drum trap.

An alternative to this is to cap off the galvanized pipe and tie this bath tub drain to another 2in. drain that's 15 feet away. Would this be better than reusing the old piping?

 

[Jeff H Young]

you currently have a drum trap and a p trap ? just cut it all off and run over to the tub tailpiece with a new p trap below just like your bottom drawing shows only ditch those 45s they arent needed

 

[jsarin1]

i cut off the drum trap and am trying to replace it with a p trap. But I can't achieve a negative slope after the p trap tail piece because the existing drain pipe is about 8 inches higher.

Can I still install the p trap if I need a vertical run to reach the drain pipe?

Hopefully this new drawing is more clear for what I'm trying to do...

 

[Reach4]

Drum traps work fine, but you are not allowed to put them in new, unfortunately IMO.

What you illustrate will not work.