heating wont turn off on the wall stat?

[streetdreamzcc]

hi guys...

have a problem with my heating system..
hot water is fine.

basically the heating is controlled off a timer, comes on no problem at the start of the cycle and goes off fine but inbetween the on or off periods controlled by the thermostat on the wall it doesnt turn off and just gets hotter and hotter...

controls are..

potterton boiler
acl drayton programmer 2 channel
acl za5 hoter water valve 2 port
honeywell heating valve 2 port
megaflow cyclinder
drayton wall stat

system is 8years old

tried changing wall stat and honeywell valve no difference at all

any guideance would be most helpful!

matt

 

[ferret]

sounds like your room stat is not wired correctly either in itself or in the wiring center matt , check these

 

[streetdreamzcc]

havnt changed the wiring in either as we bought same for same so just replaced the face plate with the same original base plate? dont think its the timer as it turns on off for both hw and ch. just went all of a sudden..
did change the wiring in the wiring centre for the ch valve but did that same wire for same wire as such...

 

[washer]

Could be your central heating zone valve seized open, or

If the radiators are only coming on when your hot water is on, the c/h zone valve could be passing.

 

[streetdreamzcc]

already changed the ch valve.. and wall stat..
when you turn the stat down at the wall it clicks (which sugests it works.. even tho we changed it, and still got the same predicament) the valve is spring return..but it still doesnt even try to close if you know what i mean, is left wide open. thanks

 

[ferret]

you need to check that the room stat is switching not just clicking you need a meter or ( dont shout sparkys) a neon screwdriver to check that when it clicks off no power is going down the switch live!! it will tell you inside the cover plate the terminals that should be switching i know its 1&3 on a honeywell stat not sure on drayton

 

[streetdreamzcc]

ahh yes maybe,... i will try that 2mz... thanks so far, for all ur effort

 

[streetdreamzcc]

ahh but i changed the stat for a new model of the same stat.... and same problem?

 

[aggis]

When it's suppose to be off.
Is the heating valve open when should be shut ?
If open.
Check the brown wire to heating valve if 240v, you've got to trace where it's coming from ?

When heating channel on clock turned off [or in off period], you shouldn't get power to the roomstat. if 240v at r/stat, clock is faulty, unless it's a permanent live to r/stat.
If r/stat turned down & 240v on switched side, it's a faulty r/stat.

If there's no voltage at clock & r/stat but 240 at brown on valve, it's wired wrong.

If no voltage at brown on valve, it's faulty or your systems piped wrongly. [ Very much doubt it, as valve is new & you say this has recentley just occured.]