washing machine standpipe height?

Question

I'm putting in a stackable washer/dryer.

The manual says to use a 1-1/2" standpipe and make it 36" tall.

Now, a bunch of plumbers had a hissy fit over the 1-1/2" standpipe, so I'm going to go up to 2". If I compare the two by volume, a 36" 1-1/2" standpipe has the same volume as a 20" 2" standpipe. So is 20" the height I should use? Or does it not work that way?

I know you're not supposed to make it too short or it'll flood, or too tall which will put too much strain on your washer pump or something. So help me out here! Thanks!

Answer 1

Whether it is a 1 1/2 ", or 2" follow the height recommendation and make it 36", because that height is determined by the manufacturer as the height the pump is capable of pumping to, and the height that protects the washer against a backwash. Most washers specify 33", and minimum 1 1/4". Roper specifies 39" Once the water is in the standpipe, it just falls. By the way, if 1 1/2" is larger than your outlet hose, it is plenty big enough. If a plumber does not like it, maybe there is a municipal regulation calling for a larger pipe. Alliance specifies either a 11/2" or a 2", and a 36" height. Amana specifies minimum 36", and does not mention diameter. If you have a shorter stand-pipe than specified, you need to install a siphon break.

Answer 2

Washing Machine Drain Height

Answer 3

Washing Machine Standpipe

Answer 4

standpipes for a washing machine need to be 2". 18" - 42" in length, per code. an 1 1/2 stand pipe cannot take the volume of water discharged by a washing machine. Put in the tallest stand pipe you can.

The reason you do NOT use 1 1/2 pipe is when the water drains through it it is more than it can handle, what happens is it ends up or most likely will create a siphon that will suck the p-trap dry leaving you with a lovely sewer gas smell in your laundry room after every load of clothes you wash. Your call.

Answer 5

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RE:
washing machine standpipe height?
I'm putting in a stackable washer/dryer.

The manual says to use a 1-1/2" standpipe and make it 36" tall.

Now, a bunch of plumbers had a hissy fit over the 1-1/2" standpipe, so I'm going to go up to 2". If I compare the two by volume, a 36" 1-1/2"...

Answer 6

The stand pipe should be about the same height as the top of the washer tub regardless of the diameter of the pipe. It should be large enough to allow plenty of clearence where the drain hose goes into the stand pipe. Also, the drain hose from the washer should not be inserted more than about 6 inches into the stand pipe (must be above max water level of tub). The hose should leave enough gap into the stand pipe to allow air to freely enter, avoiding the siphon effect. 1-1/2" is adequate for most newer thin plastic washer drain hoses, but 2" might be better for older rubber types. If you can use 2", it would be best choice for washer located in the cellar.

Answer 7

Basiclly i don't see the big deal over using a 1.5" pipe mine is only inch and a quarter abs. As far as the height to short and you are right it will flood. To long doen't matter...it don't put any strain on the pump. All it does is slow it's flow rate down that isn't straining it. Straining it would be running it with no water in it. A 1.5" 36" would be fine. If you are worried about backsplash get a rubber 1-1/4" to 1-1/5" pipe coupler.

Answer 8

A short stand pipe will allow the washer to drain prematurely when you want to use the large load cycle. Go with a 36" tall 2" pipe. I have a 1 1/2 pipe and it tends to siphon irregularly during the spin cycle The smallest clog also will cause the pipe to overflow. Good luck.