On 2008-05-02, dakota2112 wrote:

The thing that really confuses me though is that the relatively
large PVC drain pipe enters the box inbetween the valves, and exits
through the floor co-planar with the pipes but NOT inbetween them.

Is the P-trap for the washer drain visible in the basement? If not,
it is in the wall, which explains why the pipe jogs.

I'm not sure how I would even go about removing the existing valves.
If they are threaded on, I won't be able to remove them because the
pipe flexes torsionally and I can't access the pipe itself to prevent
that.

I believe they are threaded on, but someone else with more experience
should confirm that. If so, you would need to open up the wall below
the box so that you can get an opposing wrench on the connection.

Cheers, Wayne