3-port mid positioj valve positioning ??? All aspects of plumbing questions and answers, help, tips and information

[stevehayes]

how does the 3-port valve work? does it have to be positioned in a certain way, ie the hot water and central hesting flow coming into the valve or away from it, and also the flow from the boiler? mine is in the airing cupoboard and i am trying to work out how it works!!! any help and advice would be much appreciated!!!

[ericmark]

Do an internet search for Y plan. I have it on my web site www oh I'm now allowed to give you the talktalk.net web site using same name as I log on here with. But the micro-switches shown are only theoretically in real terms there are three but plan shows only one. Honeywell is the firm who standardized the wiring.

[dcc]

flow from your boiler goes into port 'ab' when the heating control calls for heat, the water will divert and come out of port 'a'. when the cylinder stat calls for heat, the diverter valve will swing to port 'b' to feed the cylinder. if both hot water and central heating are calling then the valve will go into 'mid position' to feed both.
is this what you wanted to know?