Boiler Time Switch

[Mill Hill]

Hi Everyone.

I have just moved into a not-so-new house and have noticed that the combi boiler has no in-built time time switch. It actually has a seperate thermostat time switch made by Drayton Tempus One. I have had to replace this time switch as the digital display does not work. I replaced it with the up-to-date Tempus One unit and connected it with the same wiring as had been previously done. However when operating the switch on a program it does not switch on or off the thermostat. Instead it is permanently on or off, depending on how high the thermostat has been set.

My wiring takes in a feed from the mains switch into the Tempus One unit, and also the 3 cables (L/E/N) to the thermostat switch. As follows:

From Mains into unit: Live to L, Neutral to N, Earth to earth
There is a standalone loop from L to 1 for the Live cable.

From Thermostat into unit: Live to 1, Neutral to N, Earth to 1.

http://picasaweb.google.com/antonysilverberg/House/photo#5139806645505448946

If you visit, and then select the Instructions for the Tempus One it will show you on page 4 the wiring diagram for how the unit should be set up.

http://www.screwfix.com/search.do;j...I?_dyncharset=UTF-8&fh_search=drayton+tempus#

Any suggestions as to why the switch in the unit does not work would be very helpful.

Thanks.

 

[mikely]

It is alarming to see that the green/ yellow earth wire is connected to terminal 1, live. What is this supplying, is it being incorrectly used as a supply to something? This should be connected to the earth terminal (with the un-sheathed earth of the twin & earth supply). As connected, your output is simply connected to the supply so the timeswitch will do nothing. The output (brown wire) should be connected to terminal 3 which is the output of the timeswitch.

 

[Mill Hill]

Hi Mikely,

Many thanks for your suggestion. You're right to say that the earth cable is connected to the Live cable, instead of where the other earth cable is currently connected. I also thought that incorrect.

The unit currently does nothing, as mentioned. I either have it on or off depending on where the thermostat temperature is. The actual unit switch does nothing.

Now I have changed the earth cable (green/yellow) to the earth connector - where the other sleeveless cable is) and moved the brown live cable to terminal 3.

The outcome is that the thermostat now does nothing. I have the unit timer program set to be on, so it should get the switch to work.

Is there anything else that may need to be connected. According to the actual circuit diagram there appears to be other cables using terminals 1 and 2.

Many thanks....