Radiators getting too hot

[alanrhilton]

I have a newish CH system with one 3 way valve .It sometimes becomes stuck on central heating .ie. the leaver on the 3 way valve goes all the way down and stays there ,the boiler continues to run and the rads get hot and the system won't shut down on the room stat .Switching off the isolator is the only way to shut the system down .I replaces the 3 way actuator last year and the programmer last month to no effect .I have read the article on 3 way valves and think it may be a fault with R2 Am I right ? how do I test this ?

 

[linkyplumb]

R2

 

[seco services]

R2 is a resistor.

With both heating/hw off at programmer you should have 230v on the grey wire what are you getting on the orange wire ?

 

[alanrhilton]

I can't find my multi meter at the moment but I have found that when the heating sticks on ie the rads are getting hot water when the room stat and cylinder stat are both satisfied . it is possible to restore the system by turning up the cylinder stat a bit .I previously had to turn off the system at the isolator to restore it .Is this a known fault?


Alan

 

[dcawkwell]

I have experienced similar problems on new 3 way valves of them sticking
in central heating particularly if the central heating is set on for long periods.

Setting the heating to off and giving the 3 way valve a tap and it resets.

 

[alanrhilton]

My heating is driving me nuts . When I first start the system its fine but after about half an hour it goes onto central heating only and stays there until the cylinder stat is turned up or the isolator is opened .I took the 3 position valve head off and put a new sync motor on which made no difference .I ran the valve head detached and it rotated passed the micro switches with the central heating called, should it do this? .The wiring is a right mess the sparks who did it used a pattras box and block connector rather than the Honeywell system . Should I rewire using the system box?

Alan