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Honeywell central heating programmer keeps turning on & off

Jakg
Posts: 2,267 Forumite


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?
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.
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Comments
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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
RussPerfection takes time: don't expect miracles in a day0 -
if it's correctly connected to the base plate then i'd check the wiring connections are done up tight at both ends & not arkingI'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.0 -
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.0
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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 runDon't you dare criticise what you cannot understand1 -
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.
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.0 -
Don't you dare criticise what you cannot understand0
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