Drayton T720R Wiring Help

[millz]

Hi, I recently purchased a Drayton T720R. I have just got round to wiring it up to a Worcester 24ri and the programmer/receiver is just a straight swap with the existing Drayton LP722 with no wiring changes required but with the wired room thermostat disconnected and using the new wireless thermostat the heating will not come on. The hot water works fine.
If I connect back up the old thermostat and the new programmer/receiver the central heating works fine.

How can I get the heating to work with the new programmer and wireless thermostat? Thanks.

 

[D_Hailsham]

The old stat acted as a switch between the old programmer's CH On terminal and the boiler. Now the stat has been removed, there is an open circuit there.

Presumably everything is wired into a junction box. If so, just link together the two terminals which carried the live and switched live, (not the neutral), to the old stat.

 

[maciejw1983]

Hi
I have similar problem with LP241
after changing to T720R the heating wont start the boiler
the wiring looks exactly the same as LP241 but for some reason it wont bring up the heating.
the water heats ok its just the central heating

 

[D_Hailsham]

Same answer as above.

 

[maciejw1983]

the problem is the LP241 never had a thermostat fitted to it
I never changed any wiring before fitting the T720R

 

[D_Hailsham]

the problem is the LP241 never had a thermostat fitted to it
I never changed any wiring before fitting the T720R

In that case, the T720R should work.

Does the hot water work?

Does the time control unit respond when you turn the thermostat up/down

Have you checked the signal strength?

Does the motorized valve make any noise when you turn the stat up/down?

 

[maciejw1983]

the problem is the LP241 never had a thermostat fitted to it
I never changed any wiring before fitting the T720R

In that case, the T720R should work.

Does the hot water work?

Does the time control unit respond when you turn the thermostat up/down

Have you checked the signal strength?

Does the motorized valve make any noise when you turn the stat up/down?

that's exactly the case the hot water works fine with programmed times, programmer responds to the wireless thermostat, but when heating comes on it wont activate the boiler itself nor the pump valve

 

[D_Hailsham]

"Pump valve"? I assume you mean the motorized valve - like this?

View media item 5946
or do you have two like this?

View media item 11762

 

[maciejw1983]

"Pump valve"? I assume you mean the motorized valve - like this?

View media item 5946
or do you have two like this?

View media item 11762

hi
yes i got two of them through flow ones, but they must be much older and are bigger so i thought they were pumps of some sort

 

[heheshamon]

I have just fitted the T720R everything works as it should but the pump runs on both CH & HW.

I've linked the stat wires and tried various configurations but to no avail any help would be grateful

 

[heheshamon]

After hours this evening trying different wiring configs I've got to the stage that I believe the fault is.

The new T720R seems not to like the wiring if I set the stat on one side of the programmer it calls the burners but the pump runs on HW but if I set the stat on the other side it works the pump on and off with the CH but wont call the burners.

I've left it on continuous pump due to the weather but I'm sure this wont be good for the system.

HELP!!!!!

 

[Echo the husky]

The new T720R seems not to like the wiring if I set the stat on one side of the programmer it calls the burners but the pump runs on HW but if I set the stat on the other side it works the pump on and off with the CH but wont call the burners.

I have no idea what you are talking about, you are in real danger of causing expensive damage to at least one part of the heating system.

After hours this evening trying different wiring configs ...

Do not continue fiddling with the wiring. Guessing the wiring will lead to damage or injury. Either post full details of the type of system you have, photos help too, or call in an engineer to correct the wiring mistakes.

Have you looked at the wiring diagram for the type of system you have? Why are you not following this diagram?