Honeywell central heating programmer keeps turning on & off

I bought my house back in march and it came with a Honeywell ST9400C programmer, connected to a Worcester HeatSlave 20-25 boiler with a Honeywell DT92E Wireless Room Thermostat.

Randomly it gets stuck where the programmer keeps turning on and off with a "click" each time it turns off. It started doing it every 10 seconds or so, then went away but now its come back and is doing it every 2-3 seconds!

I've tried reseating the unit on it's baseboard, all the pins look good.

Quick video of what I mean here - https://youtu.be/gF7VfyUnjH0

I've Googled to no avail so I thought I'd turn to MSE... help?
Nothing I say represents any past, present or future employer.

Comments

  • Ruski
    Ruski Posts: 1,628 Forumite
    Get onto honeywell customer services - email the link to the video and see if you're lucky - we've had some positive feedback on their customer service recently :)

    Good luck

    Russ
    Perfection takes time: don't expect miracles in a day :D
  • if it's correctly connected to the base plate then i'd check the wiring connections are done up tight at both ends & not arking
    I'm only here while I wait for Corrie to start.

    You get no BS from me & if I think you are wrong I WILL tell you.
  • Jakg
    Jakg Posts: 2,267 Forumite
    Part of the Furniture 1,000 Posts Name Dropper
    To update this - got worse to the point that I couldn't actually turn the heating on at all. No reply from Honeywell, got a replacement for £30 on eBay and now it works perfectly.
    Nothing I say represents any past, present or future employer.
  • bsod
    bsod Posts: 1,225 Forumite
    edited 18 January 2016 at 11:56PM
    too late for you, some of these Honeywell st9400c timers (made around 2010/11) are faulty and display similar symptoms eg

    flashing display and clicking relays

    everything on the timer appears normal, but the boiler/pump doesn't fire up

    or heating and hot water not working at the same time (and display flashes), but one works at a time intermittently

    switching off and on at the mains a few times can sometimes make it work

    The workaround is to go into installer mode and turn off the backlight (page 12 of the manual), or call Honeywell for a free replacement (doesn't have to be in warranty)

    put switch into run position
    hold ok and - for 8 seconds
    press ok
    there are 8 possible parameters to change, the only one that needs changing is parameter 2 (backlight) to zero (off) using +/- buttons and ok
    move slider switch to set heating or water position, then back to run
    Don't you dare criticise what you cannot understand
  • Jakg
    Jakg Posts: 2,267 Forumite
    Part of the Furniture 1,000 Posts Name Dropper
    bsod wrote: »
    too late for you, some of these Honeywell st9400c timers (made around 2010/11) are faulty

    The workaround is to go into installer mode and turn off the backlight (page 12 of the manual), or call Honeywell for a free replacement.
    I did come across this, but mine wasn't one of the faulty batch.

    The new one I bought from eBay didn't work either in the end! It looked like it worked, the lights came on etc - but it never made the circuit - unless the backlight was off (not quite the same failure as described online).

    Luckily, the replacement was part of the faulty batch - so I got in touch with Honeywell (again) and they sent me out an actual new one for free.

    Maybe I should just of got a Nest...
    Nothing I say represents any past, present or future employer.
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