sink fills up when washing machine drains

[fashx]

hi guys
need a soultion, cant get the wife of my case ,as i installed it .
my kitchen sink fills up with water from the washing machine when it drains.
The hose from the WM is conected to the spigot on the trap for the sink. the trap is conected to an 1"1/2" waste pipe

thanks fash

[Gary Swart]

The problem is your drain is too small. Modern washers dump a lot of water in a very short time and require a 2" drain.

[Gary Swart]

:eek: In rereading your question, I find a major no-no in your plumbing. Not only does the washer need a 2" drain, it should not be connected to the sink at all. I'm assuming (dangerous, I know) that when you said "spigot" you referred to the nipple that a dishwasher would be connect to. A spigot is a faucet and I seriously doubt that you have a faucet on the sink drain. Even if I have misinterpeted your description, the fact remains your washer needs its own trap and 2" drain into the main drain line. The J shaped drain hose hooks over the top of the 2" standpipe that should extend above the level of the washer's tub. This prevents the water from syphoning out of the washer and creates an air gap to prevent a backup from getting into the washer. I hope I've not confused the issue here.

[fashx]

:eek: In rereading your question, I find a major no-no in your plumbing. Not only does the washer need a 2" drain, it should not be connected to the sink at all. I'm assuming (dangerous, I know) that when you said "spigot" you referred to the nipple that a dishwasher would be connect to. A spigot is a faucet and I seriously doubt that you have a faucet on the sink drain. Even if I have misinterpeted your description, the fact remains your washer needs its own trap and 2" drain into the main drain line. The J shaped drain hose hooks over the top of the 2" standpipe that should extend above the level of the washer's tub. This prevents the water from syphoning out of the washer and creates an air gap to prevent a backup from getting into the washer. I hope I've not confused the issue here.

Thanks gary ,still stuck , the next problem is the WM is an inbuilt type with no space behind it for the trap and to make matters worse the previous occupants put up a conservatory and decided to cover the main drain ,cut the soil pipe and replace it with 1"1/2" pipe straight to the sink trap . theres only about 500 mm lenght of the 1"1/2" pipe that i have access to .

as such i am thinking of fixing the WM trap on the outside of the wall and then run 2" pipe from the trap into a tee at the base of the 1"1/2 pipe leading to the drain .


would this do the trick or would i still need to find a way of accessing the main drain directly with the 2" pipe

thanks again
fash

[Gary Swart]

Can't do that. You can not change from a large size pipe to a smaller size. I think you have a fairly complex problem that is impossible to solve much less fix on line. I suggest you contact a plumber who can evaluate the situation and give you professional advise on the best course of action. I think this is beyond a DIY task.

[fashx]

Can't do that. You can not change from a large size pipe to a smaller size. I think you have a fairly complex problem that is impossible to solve much less fix on line. I suggest you contact a plumber who can evaluate the situation and give you professional advise on the best course of action. I think this is beyond a DIY task.

thanks a billion i will do just that , i would just have to tell the wife i tried . time to get the plumber in .

THANKS for all the help
fash