On Aug 23, 8:54*pm, Bryan Scholtes wrote:
On Aug 23, 4:57*am, "John Grabowski" wrote:



I installed a sprinkler timer on a silcock outside the house, to
irrigate some new grass seed I planted. When the timer turns the water
on, there is a brief episode of water hammer before the water starts
to flow.

Ever since I put the timer on the spigot, there's been black water in
the bathroom fixtures. At first I thought it was a disintegrating
rubber washer in the toilet. But the black water has come out of the
sink and shower too.

The black water goes away after a few seconds.

I imagine I need to flush my hot water heater. But does anyone know
why this might be happening?

We are on city water. The timer had previously been installed on
another outdoor spigot, and this had never happened.

What to do?

*Is there an anti-siphon valve on the sprinkler timer?

I am going to try Sioux Chief's add-on water hammer attachment for
spigots. I've also ordered a new timer with a ball valve to try and
avoid water hammer in the first place.

We'll see if the black water comes back - I haven't used the home
plumbing today.

The black water is back - I flushed the hot water heater and it was
full of black sediment. And because I was turning the water supply to
the heater on and off (to loosen sediment) my whole house was treated
to another round of black water.

I disconnected the timer from the outside. My best theory is that
water hammer was causing black water... but I'll never know, I
suppose. Everyone seems to have an answer for black hot water, but
there is no other explanation on the Net for black cold water.