Nickfromwales Posted June 12, 2017 Share Posted June 12, 2017 Had a query for a job, and need some ideas . Bathroom ( ensuite ) with separate shower and bath, basin and WC, customers hate fans so use cross ventilation ( Windows ) when using the shower etc, don't ask. They've opted to go for a demister pad behind the large bespoke mirror and I'm wondering what's most practical to switch it on / off as required. First thought was off the lights, but with 4 lighting circuits and no guarantee which ones will be used and when, it's time to think a bit harder. Next thought is a thermistor which triggers a timer, located on the 22mm hot pipe as it enters the ensuite. Idea being that it turns on as DHW is drawn to either the bath or shower, not the basin, and stays on for say 30 mins after the pipe cools down. That's my favoured option right now, so question is, can I get a mains switching thermistor, and what would I need for a timer ? eg thermistor via a ( solid state for reliability ) relay triggering the timer / other? Thoughts plaese . Link to comment Share on other sites More sharing options...
dpmiller Posted June 13, 2017 Share Posted June 13, 2017 cylinder/pipe stat? Between the cooldown time of the pipe and demister, and the hysteresis of the stat, there should be plenty of overrun. Link to comment Share on other sites More sharing options...
PeterW Posted June 13, 2017 Share Posted June 13, 2017 How about one of these with the sensor behind the mirror itself ...? http://www.sensor.co.uk/switches/bathroom_switch/ Link to comment Share on other sites More sharing options...
Jeremy Harris Posted June 13, 2017 Share Posted June 13, 2017 I have ours (in the old house) wired to a PIR switch in the ceiling, so the mirror heater comes on for ten minutes whenever anyone goes into the bathroom. The PIR re-triggers if anyone is in there longer than ten minutes, keeping the heater on. This seems to work well, and is a lot better than the way we had it wired before, which was to the light (they are OK on lighting circuits, as they are only a few tens of watts). When it was on the light circuit we found that there were a lot of times in summer when we didn't turn the bathroom light on, so the mirror didn't demist. Now it works well all year around. 2 Link to comment Share on other sites More sharing options...
Temp Posted June 13, 2017 Share Posted June 13, 2017 (edited) 6 hours ago, PeterW said: How about one of these with the sensor behind the mirror itself ...? http://www.sensor.co.uk/switches/bathroom_switch/ Gets my vote but check they can be installed behind a mirror because the metal silvering might have an effect? You also need some way to indicate the demister is ON (I'm thinking usability rather than safety). Perhaps also add a timer? Edited June 13, 2017 by Temp Link to comment Share on other sites More sharing options...
PeterW Posted June 13, 2017 Share Posted June 13, 2017 11 minutes ago, Temp said: You also need some way to indicate the demister is ON (I'm thinking usability rather than safety). Row of low power LEDs behind the top of the frame..?? Link to comment Share on other sites More sharing options...
Calvinmiddle Posted June 13, 2017 Share Posted June 13, 2017 Nick I think you helped me solve this very issue over on ebuild!! it was a swipe on swipe off PIR switch with a panel? light and fuse to indicate if it was on or not. It works a treat, will take a picture when I get home and will hunt out the post on ebuild to link to. Link to comment Share on other sites More sharing options...
Calvinmiddle Posted June 13, 2017 Share Posted June 13, 2017 Nick Here is the thread from ebuild Demister woes 1 Link to comment Share on other sites More sharing options...
Onoff Posted June 13, 2017 Share Posted June 13, 2017 I have a couple of Telemechanique (not Schneider!), single module, DIN rail mount timers kicking around somewhere. (I used them on a bespoke crane to introduce a delay between slewing clockwise and anti clockwise. As the jib was so long what was happening was the operator would slew say clockwise, realise he'd gone too far and immediately press to go in the other direction. Or course because of momentum the arm was still moving, more "flexing" in the CW direction even though it wasn't under power. All sorts of overload issues and problems with the pawls that lock into the slewing ring. Pi$$y little 120W slew motor on the thing from memory). Off to the garage/shed for a delve! They can be feckin expensive these but if I can find them your welcome to one for nowt if you want to go that route. Link to comment Share on other sites More sharing options...
Calvinmiddle Posted June 13, 2017 Share Posted June 13, 2017 Some pics Link to comment Share on other sites More sharing options...
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