Worcester MT10 programmer

[Bill4444]

Hi, I've recently moved house which has a Worcester 28i Junior with a MT10 programmer and separate Drayton remote thermostat.

The problem is that the boiler programmer has no effect at all on the heating operation. The central heating works fine but is only controlled by changing the thermostat temp setting. The ON/OFF/TIMER switch on the MT10 doesn't do anything. The clock can be heard ticking and keeps good time.

I would like get the heating to operate via the time clock. Is there a way of bypassing the programmer with jumpers/connections on the boiler PCB? If so can this be reverse. Or is it simply the case that the unit has failed ON?

Advice much appreciated.

 

[stem]

I'm not overly familiar with this item, but as no one else has replied..... I think the MT10 is connected to the boiler by a plug in connector located behind it. have you checked that this plug is inserted correctly? Some boilers with built in timers work by selecting only the external controls for the heating (which in your case would be the room thermostat) when this plug in connector is removed.

It is possible for the timeswitch contacts to become welded together and remain permanently "on", but this is usually after a fault has caused too much current to pass through them.

Once the MT10 is removed from the boiler, it should be quite simple to test the switching operation if you have basic electrical knowledge and are able to use a multimeter.

 

[Gasguru]

The MT10 clock is one of the most unreliable clocks ever manufactured. Lost count of the number I have replaced. Classic fault is the selector having no effect.

 

[bazdaman]

+1 utter carp but dont go taking that case off to do it yourself,

 

[Bill4444]

Many thanks for your input. What would you recommend as a direct replacement. Limited web research shows that the DT20 would be a reasonable choice. Any other options?