- 7 Oct 2021
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Hi guys go easy on me 1st post. Moved into a new home and the heating system is a vaillant eco Tec plus 418 with a wireless programmable stat (vrt 392f) and 2 X 2 port zone valves one for HW & other for CH. Since I moved in the system has not been working as a heating system should. I have replaced what I thought was the problem the programmer with a new VRT 350f and also replaced the CH zone valve as the lever was knackered and was staying open all the time even with power off. Now when I switch the boiler on and off both valves open and close as they should when power disconnected and the HW valve seems to work correct with the cylinder stat. But the CH valve seem to stay open all the time soon as power is switched on. I have disconnected the receiver from the BUS to eliminate the programmer being an issue and the valve still stayed open. On further investigation I have found that there is a permanent live feeding the brown of the CH valve in the wiring centre which is obviously keeping it open all the time. How is this supposed to be switched with a wireless programmer/stat. In the boiler wiring centre I have a switch feed in terminal 4 which is controlled by the cylinder stat and a link between 3&4 is this correct? Any help would be much appreciated before I get vaillant in.