Older home, unknown pipe in washer drain

[Glen H]

I have purchased a house built in 1955. The washing machine drain has this rubber hose in it. I’ve tried to pull it out but seems to be pretty secure. Does anyone know what this is and why it is there. Prior owner doesn’t remember.
Thanks in advance.

 

[havasu]

Should be a twist and pull out hose.

 

[Glen H]

I’ll try that. Do you know what its purpose might be?

 

[havasu]

Some of the high efficiency front load washers really pump out the water. I tried this method to stop the water from overflowing out the end of the pipe at my other house. I solved it by installing a rubber boot with a one way air vent. I got it from Sears years ago. This house has good plumbing, so I just shove the washer hose and it drains nice.

 

[Glen H]

I was concerned about the washer volume also. Do you have a picture or more info on that one way air vent?

 

[havasu]

I was unsuccessful in finding the actual part that I used (probably discontinued) but this serves as a similar product.

 

[Glen H]

A million thanks. I didn't know this even existed.

 

[PerplexedPlumber]

We found that the drain port with the raised edge inside, with a drain line that has a rubber fitting that seats into this edge, seals better for the newer types of washers. With the front-loading washers, a drain line that doesn't have this fitting used in the traditional open-line drains (knockouts opened) must be secured to empty at a certain height in the drain - too short and there may be liquid coming out of the drain port, too long and you can siphon back drain water into the washer. The manual for the washer will provide those specifications. I think for ours it was 5 1/2" to 6 1/2" inside the drain port.

 

[havasu]

So basically, they had designed an air gap, right?

 

[Twowaxhack]

Indirect connection, not an air gap. The hose has to stay at a certain height or the machine won’t hold water, it’ll siphon itself.

Ive never heard of one sucking trap water back into the unit.

 

[PerplexedPlumber]

On the possibility of backing up: This is my assumption. If you put the drain line for a front-loading washer too far in, at the rate the pump runs if you aren't far enough above the trap, when the pump stops, it may pull water back in. This is one potential cause that I've seen listed when people complain about odor in the washer. (First step is to drain and clean the lower port and door seal, but not all front-load washers have this drain.) Siphoning of the tank sounds reasonable too.

*I've seen water in the drum after a washer cycles; this may occur more often when the washer wasn't leveled.