View Full Version : Can I run a washing machine off a 3/8 line?
z2world
Aug 13, 2007, 04:15 AM
Hope someone out there can help me. My wife wants to move the laundry out of the basement to the 2nd floor. The room has a regular bathrrom sink already. I believe the line is 3/8. I replaced the sink with a laundry sink and was working on splitting the inlet line with a "T" so that the washing machine inlet hoses would receive water. However, will the existing 3/8 line be adequate? I don't have enough knowledge to run new 1/2 inch pipe from somewhere else to that room? Will the pressure be enough? Would it be enough for a new front loader model that she wants to get or will it read some kind of a water pressure error?
Thanks in advance... bob.
scirocco70
Aug 13, 2007, 02:03 PM
You won't have a pressure problem with 3/8" line, you'll have a volume or flow problem.
3/8" is considered undersized for just about everything more than a drinking fountain... are you sure the existing line isn't already 1/2"?
In any case, code will require 1/2" and the problem you face (besides very slow filling) will be increased erosion of the inside of the pipes due to excessive water speed in the pipes. 8fpm is supposed to be the max, I think. I have no idea how true the erosion fear is, it seems to me personally like it would take a AWFUL lot of water to erode through a copper pipe at anything less than 100fpm.
BUT... I am not a plumber, so...
Of course, a low-water-use front-loader will not have the same problem with an undersized line as a large conventional washer, so you're on the right track there. If it were me, I'd probably just go with what's there.
~aaron
.
labman
Aug 13, 2007, 03:27 PM
Usually lavatories have a 1/2'' X 3/8'' angle stop screwed to a 1/2'' pipe coming out of the wall. As long as you can shut the water off, you could replace the angle stop with a 1/2'' ball valve and then a 1/2'' tee. That would give you a faster fill, but still might not meet code. The trouble with not meeting code is that if you ever sell, you might have to pay to have it brought up to code.
speedball1
Aug 20, 2007, 10:14 AM
You may use 3/8" for a washer but expect a longer fill and rinse cycle. If you have a 1/2" stub out with a 1/2" X1/4" compression angle stop I would change that stop for a three way angle stop,(see image) and pick up the washer through that. Good luck, Tom