washing machine drain problem

[DJT]

The picture is showing a washing machine drain with a hot water heater overflow drain tied in. Before I hooked up the washing machine I tested the drain by running the water through from the supply line. The problem is that the water backs up and comes out through the hot water heater overflow drain and into the drain pan of the hot water heater. I have raised the hot water heater off the floor on lumber framing twice thinking it just wasnt high enough but the problem is still happening. The drain pipe is tied into other drain pipe under the floor which is vented through the roof. What is the Solution?

 

[johnjh2o]

First off the drain for the pan should not connect to the DWV system. Second the washer drain is not vented properly. What you have there is a full S-trap that is not allowed by any code. The way that is set up if you get a sewer back up it will fill and overflow you heater pan with sewerage. The pan drain should be piped to the outside above the ground.

John

 

[Matt30]

I love home plumbers! They keep us pros in business

.......atleast i hope that was a home plumber.

Anyways, johnjh20 is right. Get that pan drain right out of there and have an air admittance valve installed to get rid of that s-trap

 

[LiQuId]

where is the washing machiene located? I assume its above this picture and if so you have a 3rd problem in that the maximum permitted fall into a trap is 3' what you have there will syphon due to s trap, and momentum syphon due to excessive fall.

 

[DJT]

yes Matt30. you are correct. I've given up on doing this DIY project and am having a professional plumber take it from here. The worse part is everything worked fine before I had this brilliiant revelation of connecting the drain pan to it and putting in the trap because there wasnt one there. I had an unfortunate event one time where my hot water heater rusted out at the bottom and flooded and saturated all the carpet in my business. Where the hot water heater is located it is extremely difficult to run the line to the outside. Guess I screwed up on the trap also.

 

[johnjh2o]

If it worked before then there may be a trap under the floor and by double trapping the line you may have caused the problem you are now having. Today you are no longer allowed to have the washer trap below the floor.

john

 

[LiQuId]

You could always have an air gap installed on the drain line, this would allow you to connect any possiblle spillage from the water heater pan into the Drainage.
Where I live these are often used in small commercial establishments utilizing small electric tanks.

Also, john's theory sounds likely.