Reversing water flow in classic hydronics

llamaboy

I am a student taking a boiler class this fall. We are using Dan's classic hydronics book, and it it he mentions that in Europe they use a 4 way mixing valve and a timer. I asked my teacher what kind of mixing valve it was exactly and how it was configured.
I was wondering if anyone could help fulfill my curiosity. Thanks.

llamaboy

What I am referring to is on page 86 of Classic Hydronics, in chapter 6 "Classic One-Pipe."
"The circulator comes on and runs hot water clockwise through the four-way mixing valve and the loop of a square pipe, feeding all those panel radiators along the way. The end of that loop is getting cool, and those final radiators are no so hot. So after a half-hour of flowing clockwise, the timer shuts off the circulator and the relay reverses the position of the four-way valve. Then the circulator restarts, but now it's moving the water in the opposite direction around the big loop. The supply water goes this way and then that way, and then this way, and everyone upstairs stays cozy."

FranklinD

There are a few threads that deal with this on this site, but only one that I remember reading recently. He had good schematics and a hardware list iirc. I'll see if I can find it.

FranklinD

Here's a link to a PM article that deals with 4 way valves...I'm not too good at inserting links and such into posts. Sorry. Also, you can use the search function to find them...just search for "4way".

Article:
http://www.pmmag.com/Articles/Column/625c61cba20d7010VgnVCM100000f932a8c0____