central heating

[jocky]

Hi all, im having some trouble with my central heating, if there is some trouble shooting whizz out there can help please,

The systen is a megaflo unvented sys the motorised valve on the CH is a drayton ZA6

when the power supply is switched on the gas boiler and pump run on the central heating side only although the CH is not switched on, on investigating this I found that it is running against a closed valve, when the CH is called for at the progammer or the room stat the motorised valve operates and opens and closes the valve normaly, then when not called for the sys continues to run against the closed valve, I have removed the continuous feed on the CH at the wiring center and found that the the hot water side operates correctly, any suggestions?.

 

[tabs]

Power to the boiler is fed through prog-stat-mv - there is a fault somewhere that is still feeding power on CH. Most likely stuck microswitch on the MV

 

[jocky]

Thanks tabs, I got a new actuator for it and it appears to be working, the micro switch would appear to be the only thing left to check, I take it if the micro switch is working you would hear it clicking on if pressed manualy?.