V3+ not calling for heat

Laticsforlife

Bit of background - bought a Hive but realised it was not WiFi, so bought this instead.

So the boiler (Morco GB24) has a simple timer switch (heating only being controlled). Fitting the Hive meant using grey wire 4 to the NO side of the timer switch and linking Common and Live on the Hive side leaving the switch in the always on position. It worked fine.

So I used the app guide and fitted grey wire 4 to the same NO at the boiler, and to the left side of the receiver in the heating side.

It all connected to the WiFi etc, and when I increase the heat, the relay clicks and the white light comes on, but no call for heat.

I did configure it to yellow for combi boilers.

Can't quite work it where I've gone wrong, power at both ends but no heat.

Any thoughts?

NB the professional installation shows 2 slightly different wiring if it's 'potentially free' or 'switched live'. One has a link wire, but the app didn't suggest a link.

policywonk

This link contains the installation guide to your boiler.

GB24 & GB30 Series II User & Installation Instructions.pdf (morcoproducts.co.uk)

Look at Page 11 and more carefully page 16. A few things can be observed.

1. This is switched using mains power, that is Switched Live.
2. The timer has no role in controlling hot water.
3. There is a possibility of an original manual timer being installed. Does one presume right that it has not been installed?
4. The chocolate strip connector has a grey wire and red wire, on the left of the incoming power to the boiler., These two control the decision to call for heat.

Suggestions, to help you through the logic.

1. Turn off the power to the boiler. Remove the wires that screw into the points where the Room stat should fit (label them as you remove them), and fit a bridging wire between the two screw points. Turn on the boiler. Does the central heating fire up? Assuming it does, go back and undo this step.
2. Now check the wires going to wherever you've fitted that Tado wired stat.
   1. Does whatever wire connected to the Red Wire on the chocolate strip, lead to LIVE at the Stat? If not, fix the route.
   2. Does whatever connected to the Grey Wire on the chocolate strip, lead to the NO point on the Stat? If not, fix the route.
   3. Dont worry, there's nothing apart from terminals in that backplate. If you had the wiring wrong you probably didnt break anything.
   4. When (a) and (b) are correct, turn off the power again, and fit a bridging wire between the LIVE and NO terminals at the Stat. Turn it all again. Does the boiler experience a call for heat?
   5. If (a), (b) needed a wiring change fix it, then turn it off, remove the bridge and turn it all on again, refit the Wired Stat and it should work.
   6. If there isn't a wiring change needed, then your only problem is the Wired Stat.
      1. So, turn it all off.
      2. Undo that bridge in (d).
      3. Turn it on.
3. Undo the flap where the batteries are placed, and make sure that they are oriented correctly and making good contact. If you have a multimeter double check. Now grab a cuppa and stare at it, asking what you've done wrong with the configuration on the App, or come back here.

Laticsforlife

Many thanks for this, I'll work through this step by step and report back.

policywonk

Presumed it was only one wired Tado stat you fitted with an Internet bridge to replace the Hive.

Laticsforlife

Yes just one fitted .

Laticsforlife

So I've worked through this and it's still not right.

I removed the link wire at the boiler connection between the stat wires (leaving the existing clock attached to the other side).

With that out the boiler doesn't call for heat no matter what I set the timer switch to so that is obviously creating the link to call for heat.

So I presumed all the Tado stat has to do is either make that link or not make it and so long as the timer is in the on position it would work.

Mains power is drawn from the boiler using brown and black wires with earth wires at the Tado end in the earth terminal in the right.

Then I connect one grey wire to NO at the stat and the other wire (a different black wire) to COM. Those were originally grey and red on the far side of the block in place of the link

I've tried attaching a link between COM and live or between COM and NO (and even tried NC), but none turn the heat off.

It's as if the Tado stat is on regardless.

But the boiler calls for heat even when the heating light is off (the remote is working fine, I can hear the relay clicking on or off and the light comes on and goes off.

Laticsforlife

BTW I was a bit confused re step 1, if I remove the wires from the stat block (ie the wires to the manual timer) then what's the point of connecting the 2 empty choc blocks they aren't then holding anything?

As far as I can see one of the stat choc ports has a live red wire in (it has 2 wires in), and a grey wire to the other port.

Laticsforlife

Is it possible that the Tado relay is faulty if it's not switching off, using an electric end touch type screwdriver it's lighting up on the grey wire whether or not it's supposed to be on.

policywonk

When the front of the Tado wired stat is removed, don't forget that it cannot make any relay contact because those pins are in your hand.
* So if the NO wire is live that voltage is coming from somewhere else.
* Are you saying that the wire to the COM side comes from the programmer?
Sorry am a little confused.

Laticsforlife

The wire to COM (in the Tado) comes from the left wire of the programmer per page 16 of the manual (a red /red & white set of wires, live?). Is this wrong?

policywonk

@Laticsforlife

Almost there. From the drawing on page 16, it seems authority to start the boiler is arranged like this:

1. Refer to the photo at the top of page 16. The timer (when removed- and this is your required configuration) needs a loop, or bridge between those two right hand points on the choc strip.
   1. Kill the power to the boiler.
   2. Make sure that loop is in place.
2. Refer to the drawing at the bottom of page 16. Remove the two wires for the STAT part of the chocolate block (the two on the left).
   1. turn the boiler power on
   2. test the pins with your test screwdriver
      1. The one marked as FEED on the drawing, should glow as LIVE. Note that. Note to label it as FEED at the boiler end and COM - but not now!
      2. The one thats marked as RETURN on the drawing should be labelled as RETURN at the boiler, NO on the Tado.
3. Turn off the boiler.
   1. label the wires at the boiler end and at the Tado Stat end.
   2. Power it back up. Should work.

Come back if you meet a new curveball!