Ricco Posted July 23, 2019 Share Posted July 23, 2019 Hi I have 15 Heatmiser Neostats installed in the house (7 downstairs and 8 upstairs) split across 2 wiring centers. The problem have been facing is that the back light on some of the thermostats comes on randomly when you are nowhere near it. This doesn't sound like a massive problem when you type it out, but lying in bed at night and the room lighting up is not ideal! It is happening in 3 bedrooms, ensuite, hall and living room. I have tried almost everything but am nearly out of options. The problem stays in the room when you swap the face plate or back plate with a room that doesn't light up on it's own. I have changed the wiring to use different pairs. I have removed it from the back box and allowed it to dangle down the wall away from the metal back box. I have turned off all WiFi. I have turned off the NEOHUB so the mesh network is not in force. I bought ferrite beads to put round the CAT 6 cable at both ends and it made no difference. I am contemplating re wiring a few (up stairs is do-able but downstairs will be next to impossible!) It is currently wired with CAT 6 UTP Heatmiser technical support were of the mindset that it was to do with sudden humidity change, but in a bedroom in the middle of the night any change in humidity is very gradual. Any help of advice would be much appreciated! Thanks Link to comment Share on other sites More sharing options...
Temp Posted July 23, 2019 Share Posted July 23, 2019 Can they tell you how the proximity sensor works? Some sort of capacitive sensor or does it bounce IR off you? I think you have done everything to eliminate a faulty stat. I'm wondering if they have a design issue? Proximity sensor too sensitive? Picking up mobile phone? Noise on the wiring? Link to comment Share on other sites More sharing options...
lizzie Posted July 23, 2019 Share Posted July 23, 2019 i have heatmiser......some of my stat lights come on randomly too, some never. come on. Tried all sorts now given up. Be interested to see if you solve it. There is a dedicated heatmiser user group forum but sorry cant find the link. Link to comment Share on other sites More sharing options...
Temp Posted July 23, 2019 Share Posted July 23, 2019 I had a look at the manual and unfortunately there doesn't seem to be an optional feature to disable the proximity sensor. Earlier Heatmiser stats only light up when you press a button as they don't have a proximity sensor. Worth asking them to consider adding such a feature as pretty sure it would just be a software change. Link to comment Share on other sites More sharing options...
Temp Posted July 23, 2019 Share Posted July 23, 2019 Their SmartStat has a feature called Ambient Light Dimming which if enabled turns down the brightness of the backlight when the room is dark. Link to comment Share on other sites More sharing options...
Jeremy Harris Posted July 23, 2019 Share Posted July 23, 2019 FWIW, our Genvex controller has one of these sensor-type screens, that is supposed to light up when you wave your hand over it. That works randomly, too, and I've yet to find out exactly where the sensor is that turns the backlight on, or why it behaves as it does. My guess is that it's just typical flaky technology. Seems normal now for manufacturers to produce flaky stuff. Perhaps it's just a function of a whole generation growing up with tech that falls over, needs rebooting, constant updates, etc, so we don't have product designers who value making things that just work reliably, all the time... 2 Link to comment Share on other sites More sharing options...
Ricco Posted July 24, 2019 Author Share Posted July 24, 2019 Hi Heatmiser support have been unable to give me any indication as to how the proximity sensor works. i tried something last night which has been the first successful test.... I wired the master bedroom stat into the wiring centre with a long CAT6 patch cable running up the corridor from the bedroom to the wiring centre. This worked and once reworked the back light did not illuminate on its own! So.... what i am trying to figure out now is how to make the fix permanent (the wife said she is not happy with patch leads running up the corridor!!) The cable must be picking up interference and causing the back light to illuminate. The electrician who wired them in used CAT6 unshielded cable with a plastic spline running up the cable to keep the pairs apart (not uncommon for CAT6) this was probably because I was getting the data points wired with CAT6 He said he has used CAT5 or 6 cable to wire these in before with no problems. The cable I have used for testing was a CAT6 patch lead so doesn’t have the spline in the centre, so don’t know if this means with the cables being closer together it aids in the cancellation of any interference. The instructions say it should be wired with CAT5-FTP ( not just shielded but each twisted pair having a foil wrap) or BELDEN 9538 cable. Because rewiring won’t exactly be an enjoyable task I want to do it once but not cost myself the earth with specialist cable. Would normal UTP CAT5 without the spline do? Or potentially just change the route of the existing cable (if it’s length permits) Link to comment Share on other sites More sharing options...
Temp Posted July 24, 2019 Share Posted July 24, 2019 20 hours ago, Ricco said: I have changed the wiring to use different pairs. Not sure exactly which model of the stat you have but the one I've been looking at has 4 wires (+,-,A1,A2). This will probably seem very obvious but the pinout is + A1 A2 - so make sure the pairs are connected like this.. Pair 1: + & - Pair 2: A1 & A2 not Pair 1: + & A1 Pair 2: - & A2 If that's OK you might try adding a 100nF ceramic capacitor between + & - at the stat end (but don't put one on A1/A2). Link to comment Share on other sites More sharing options...
Ricco Posted July 24, 2019 Author Share Posted July 24, 2019 Thanks for this... the wiring seems to be correct as you have suggested. A ceramic capacitor is something I haven’t tried, what would this do? Would linking the + and - not short it out? Link to comment Share on other sites More sharing options...
vfrdave Posted July 24, 2019 Share Posted July 24, 2019 tinfoil wrap your existing cable where possible and see if that eliminates the issue Capacitor Guide:- http://www.capacitorguide.com/coupling-and-decoupling/ Link to comment Share on other sites More sharing options...
Ricco Posted July 30, 2019 Author Share Posted July 30, 2019 On 24/07/2019 at 12:12, Temp said: If that's OK you might try adding a 100nF ceramic capacitor between + & - at the stat end (but don't put one on A1/A2). So.... the saga continues... I have installed a 100nF ceramic capacitor between + & - at the stat but no change :( Any other suggestions, should i try more than one capacitor in the stat? Link to comment Share on other sites More sharing options...
Onoff Posted July 30, 2019 Share Posted July 30, 2019 Snubber? Maplin used to be the easiest place to get them. Something like this. https://cpc.farnell.com/ampohm-wound-products/fe-sp-hdr23-100-100/contact-suppressor-0-1uf-100r/dp/FT00715 Or a ferrite bead over the cable: https://m.ebay.co.uk/itm/Split-Ferrite-Ferrit-for-Cable-6-9mm-Gray-Mains-Filter-Emi-RF-Filter-Clamp-Grey/171851671264? Link to comment Share on other sites More sharing options...
Temp Posted July 31, 2019 Share Posted July 31, 2019 (edited) That snubber is a 100nf capacitor. Edit: Actually its a 100nf capacitor and 100R resistor but the capacitor is the main thing. Edited July 31, 2019 by Temp Link to comment Share on other sites More sharing options...
Temp Posted July 31, 2019 Share Posted July 31, 2019 The only other thing I can suggest is trying to modify a stat to put a switch in series with the backlight but they may use multiple LED to illuminate the buttons - so working out where to add a switch might not be easy. Running the specified screened cable might work but if you did that and it still happened I wouldn't be totally surprised. At least you could complain to Heatmiser. I think the manual said version 2 of the stat has a proximity sensor. So perhaps Heatmiser could give you a version 1 without proximity sensor? Link to comment Share on other sites More sharing options...
dpmiller Posted July 31, 2019 Share Posted July 31, 2019 13 minutes ago, Temp said: That snubber is a 100nf capacitor. ...with 100 ohms in series. makes a difference... Link to comment Share on other sites More sharing options...
Temp Posted July 31, 2019 Share Posted July 31, 2019 I wouldn't expect the resistance to make a difference in this case but I guess they are cheap enough to try. Link to comment Share on other sites More sharing options...
Ricco Posted July 31, 2019 Author Share Posted July 31, 2019 Would a higher rated ceramic capacitor make any difference? Is the train of thought RF interference / electrical interference as the cables do share trunking with 240v cable for a bit or some sort of voltage drop over the run of the cable? Link to comment Share on other sites More sharing options...
ProDave Posted July 31, 2019 Share Posted July 31, 2019 It is not unknown for some designers to "get things wrong" I had a similar issue with my heat pump, with the thermostat input spuriously triggering occasionally and I fitted both a snubber and a pull down resistor to cure the problem. The designer had used a sensitive high impedance input to detect a 240V on / off condition, with no debounce or filtering at all. Link to comment Share on other sites More sharing options...
Temp Posted July 31, 2019 Share Posted July 31, 2019 6 hours ago, Ricco said: Would a higher rated ceramic capacitor make any difference? Is the train of thought RF interference / electrical interference as the cables do share trunking with 240v cable for a bit or some sort of voltage drop over the run of the cable? Yes. The idea of the capacitor is to ensure any noise is coupled into both the +ve and -ve line equally. If both +ve and -ve are hit with the same value spike the difference between them stays the same (12V). Link to comment Share on other sites More sharing options...
Temp Posted July 31, 2019 Share Posted July 31, 2019 Another idea to consider if everything else fails and you are considering replacing the cable... A CAT 6 UTP cable normally has 4 pairs in it. 2 pairs are used by the stat leaving 2 pairs (4 wires) unused. You could try connecting all the unused wires to ground at the hub end. Grounding the unused wires wouldn't be as effective as using screened cable with the screens grounded but might be worth a trying. Its a bit messy if the hub end uses proper network connectors. I'm thinking you would need to cut the connector from the wire, split out the unused wires to form tails, trim and replace the cores the stat uses into a new connector, crimp, strip insulation from the tails, crimp/solder on a ring tag, fix ring tag to ground on the hub. Something like that anyway. Link to comment Share on other sites More sharing options...
Ricco Posted September 9, 2019 Author Share Posted September 9, 2019 So the sage continues!! Some of the thermostats continue to randomly light up and i have tried the following to get it fixed. The problem stays in the room when you swap the face plate or back plate with a room that doesn't light up on it's own. I have changed the wiring to use different pairs. I have removed it from the back box and allowed it to dangle down the wall away from the metal back box. I have turned off all WiFi. I have turned off the NEOHUB so the mesh network is not in force. I bought ferrite beads to put round the CAT 6 cable at both ends and it made no difference. I bought ceramic capacitors and installed a 100nf across the 12V ports on the thermostat I got the supplier to swap out the thermostat and i replaced the back plate and thermostat I got a new wiring centre and swapped it out. I installed a new CAT5 cable following a route through the loft not close to any other cables. I installed a new shielded CAT6 FTP cable through the loft and also followed a route that it did not run along side other cables or cross them. I used the wire in the shielded CAT6 and earthed it and earthed the metal back box I turned off every circuit in the house (except heating) and it continued to flash. I connected a flex and a plug top to the mains supply of the wiring centre so it was powered by a different circuit and it continued to flash. I connected it with a CAT6 patch lead run through the landing and it stopped flashing, so to identify if it was the cable or the route i got the previously installed CAT5 cable out of the loft and connected it through the landing and it only flashed once!!! So any suggestions would be appreciated as having the cables lashed across the floor of the landing is not exactly ideal!! Link to comment Share on other sites More sharing options...
ProDave Posted September 9, 2019 Share Posted September 9, 2019 24 minutes ago, Ricco said: I connected it with a CAT6 patch lead run through the landing and it stopped flashing, so to identify if it was the cable or the route i got the previously installed CAT5 cable out of the loft and connected it through the landing and it only flashed once!!! So any suggestions would be appreciated as having the cables lashed across the floor of the landing is not exactly ideal!! Run a new CAT6 cable under the landing (following the route of your test cable as close as you can) and see if that fixes the issue. Is the length of cable to this thermostat radically different to all the others? Link to comment Share on other sites More sharing options...
Mattg4321 Posted April 25, 2021 Share Posted April 25, 2021 Having this same problem. About to get lynched by the wife. Is there a fix for it, or a way to turn the damn proximity sensor off? Link to comment Share on other sites More sharing options...
Temp Posted April 25, 2021 Share Posted April 25, 2021 I don't think all of their stats have the proximity sensor... http://faq.heatmisershop.co.uk/2958602/Does-the-neoAir-v2-have-a-proximity-sensor No the neoAir v2 does not have a proximity sensor so the keys do not light up on approach. But you need to check if that model is a suitable replacement as they make so many different versions. Link to comment Share on other sites More sharing options...
Mattg4321 Posted April 26, 2021 Share Posted April 26, 2021 I really need/want a hard wired stat so the neoair is out. perhaps I’m going to have to try and source a neostat v1 second hand. Absolutely crazy really. Will speak to heatmiser today. Link to comment Share on other sites More sharing options...
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