central heating controller swap no CH but have HW

Edward4224

Hi

I am trying to swap over my old central heating control for a new controller and thermostat.
The old one is a Grasslin Towerchron QE2 and the new one is a Drayton MiTime T720R
The old system worked just fine. The system is an open header hot water tank type system.

Problem : -
No central heating only hot water . Unless I go upstairs and use the override on the 3 way valve control then it will leap into life. It doesn’t matter if I press the override button or push the manual lever on the valve it will then start and the radiators will get hot.
What I did : -
I changed over the back plate (as the old standard one didn’t fit the new controller because of plastic lugs) I did this one wire at a time and took photos so am sure it’s the same as before.
Setup the controller as instructed in the manual and set hot water and CH to “ON always”. (while testing) and set the thermostat to 30deg (again just for testing to make sure it’s on)
If I put the old controller back onto the new back plate everything works just fine.

Any advice gratefully received

Eddy

getmore4less

Use the old controller and just get programmable thermostat(s)

is most setups you don't need to change the controllers as all the timings are moved into the stats.

Edward4224

HI

Sorry not mentioned in the OG post. But one of the main reasons for the change is the old controller is the wrong colour for the new kitchen so I wanted one that matched the new colour scheme. I did look for a new thermostat for the old controller but could not find one and was getting confused so thought if I buy a set that takes a standard backplate then no hassle just swap them over. HAha ha So I would really like to get the new one working if possible

getmore4less

http://www.draytoncontrols.co.uk/sites/default/files/MiTime%20Pack%201%20(I.%20Guide).pdf

have you checked the wiring in the old plate is the same as the new one?

Edward4224

Hi
yes I have. The wiring diagrams are exactly the same on the back of both controllers

Eddy

getmore4less

Also the existing stats will be wired in somewhere you will probably need to do something to them

Edward4224

Hi

The old stat was wireless as well but when I removed it from the wall I found the old wire from the previous install uninsulated and pushed into the wall cavity. I will fish this out and insulate the ends but i want to cut the power to the whole house before I do this as its an unknown wire and I may well short it while trying to fish it out so it will have to wait until the weekend.
To bypass an old stat do you open CCT it or short it?

ps thanks "getmore4less" for your help

Eddy

getmore4less

The old wireless probably has a separate receiver for the room stat that will need removing from the system.

You could set to max as well and that may switch the heating on which will indicate that may have been your issue if you had shut the old wall stat off.

The other end of that wire is probably somewhere near the receiver.

Edward4224

would the receiver be in the airing cupboard with the 3 way valve control and junction box? there is definitely no receiver anywhere near the boiler. (I assumed the receiver was built into the old controller like the new one)

stator

Edward4224 wrote: »

would the receiver be in the airing cupboard with the 3 way valve control and junction box? there is definitely no receiver anywhere near the boiler. (I assumed the receiver was built into the old controller like the new one)

That's where it is in my house

Edward4224

Hi This sounds like we might be onto something.
Im searching google for an image of the box in my airing cupboard but cant find one. Photo will have to wait until I get home.
But its gray and has honeywell written on it with one button and two LED's would a Grasslin Towerchron QE2 controler have a honeywell receiver?