Replacing Honeywell Thermostat to Nest Wireless Thermostat

[Iggifer]

Overriding the timer will most likely solve your issue. If the controller is not telling the boiler to fire, it's irrelevant if the stat is, otherwise your heating would fire all the time.

It depends what kind of timer you have, if it's an old school rotary one, there will likely be a switch with a O, I and a little clock. Switch it to I, or you could pop the tappets for 11pm in and see if it fires at 11.

If it's a digital one, there will likely be a button/switch to switch from timed to 'constant' or 'run' or maybe 'override'

If you can't work it out, let us know what make/model it is, I'm sure someone will know the answer

 

[NLM1990]

yes it is on constant with me but it's still not calling for heat when I increase the temperature on the Nest.

 

[Iggifer]

Does the boiler fire if you activate manual heating on the Heat Link?

 

[NLM1990]

Does the boiler fire if you activate manual heating on the Heat Link?

nope nothing at all

 

[Iggifer]

OK then it's a wiring fault.

To clarify, have you wired as follows:

From Boiler to Heat Link

Permanent L+N to L+N
25 to 3
26 to 2

From Heat Link To Stat
T1 to T1
T2 to T2

 

[NLM1990]

I've done exactly that but I haven't linked T1 & T2 as im not placing the Nest thermostat in the same position as my old Honeywell.

 

[Iggifer]

Oh I see. Well, i'll be honest, I'm stumped. What I, personally would do now, is to put the cables from 2+3 into a connector block, and see if the boiler fires up. That eliminates any issues with the timer side of things.

If you take that route, make sure you turn the power off first obviously.

 

[EFLImpudence]

Oh I see. Well, i'll be honest, I'm stumped. What I, personally would do now, is to put the cables from 2+3 into a connector block, and see if the boiler fires up.

Yes, good idea.

T1 and T2 are for use when NOT using an RF (radio frequency remote) thermostat.

Are there settings to tell the receiver which it is supposed to be doing?

 

[Echo the husky]

Failing that, posting some photos of the wiring may show the problem.

 

[Iggifer]

Yes, good idea.

T1 and T2 are for use when NOT using an RF (radio frequency remote) thermostat.

Are there settings to tell the receiver which it is supposed to be doing?

Yea I missed the bit about the OP choosing the RF option. With the V3 Nest there are status lights for DHW and CH on the Heat Link, but the OP pressed the manual override on the heat link which is a manual override, so presumably closes the switch between 2/3 and it didn't fire.

If the cables are in the Heat Link and boiler correctly, the problem lies elsewhere.

OP - check your terminations, check you haven't trapped any insulation under the screws

 

[NLM1990]

I'll try and get some pictures up tomorrow and hopefully get it working.

thanks all.

 

[NLM1990]

just a thought...would I need to jumper another bridge wire from the Live mains to terminal 2 on the Heat Link as I've seen that done on a few videos online?

 

[Echo the husky]

No link from live to the switching terminals. If you have a timeclock built into the boiler this will need to be set to on.