oldtimer1 Posted February 27, 2006 Share Posted February 27, 2006 A quick sketch/diagram of how a standard room thermostat to override a fan speed controller works. 1 Link to comment Share on other sites More sharing options...
OCC Posted February 27, 2006 Share Posted February 27, 2006 (edited) Hi, Just thought i'd carry it over to forums (was in pm) incase this will help other people or any leccys will know any ways of doing this. What I would like to do is have my Fans Idleing via a B&Q Fan Speed Controller so theres some air movement. When the temp gets too high, I would like my Habistat Cool Control Thermostat to kick in and give the fans full power. However, the way the Habistat is wired it doesn't seem atatll easy to do without some possible modifications or some other way. The habistat is just an in/out setup. What ot1 pictured is for a Honeywell, although this has helped me a lot I still can't get mine going unfortunately due to the Habistat wiring as the neutral gets turned off as well as the live when the Habistat turns off. Thus there is no neutral for the fan speed controller/fan. If anyone has any ideas, I would be most grateful, I have just included a quick drawing of the in/out habistat. I do not know if it is possible what I want to do without some other components. Many thanks Edited February 27, 2006 by OCC Link to comment Share on other sites More sharing options...
oldtimer1 Posted February 28, 2006 Author Share Posted February 28, 2006 Try it this way. Link to comment Share on other sites More sharing options...
SirBob Posted February 28, 2006 Share Posted February 28, 2006 cheers ot1, thinking of doing this soon, Any chance we could get this pinned? Link to comment Share on other sites More sharing options...
EnigmaticOne Posted February 28, 2006 Share Posted February 28, 2006 That is so easy to understand, I think I would be confident to try it. This could probably do with pinning at the top of the subforum. So many people ask about this. EO. Link to comment Share on other sites More sharing options...
Jowzer Posted February 28, 2006 Share Posted February 28, 2006 Hmm...what I need to be able to do...and I'm sure loads of other peeps too, is to have fans idling at lights off, then kick into a higher idle speed when thermostat kicks on. At no point should my fans run at max (noise and outlet constriction reasons). Any idea's on that? (2 output relay/2 dimmers and a thermostat?) Link to comment Share on other sites More sharing options...
oldtimer1 Posted February 28, 2006 Author Share Posted February 28, 2006 Hmm...what I need to be able to do...and I'm sure loads of other peeps too, is to have fans idling at lights off, then kick into a higher idle speed when thermostat kicks on. At no point should my fans run at max (noise and outlet constriction reasons). Any idea's on that? (2 output relay/2 dimmers and a thermostat?) This is live only connections for preset low night fan speed controlled by the lighting timer relay, lights on will switch to higher preset fan speed. It would be easy to adapt the circuit go to full fan speed or a third fan dimmer by adding a thermostat to override both fan dimmers as a third option to deal with high temperatures. Link to comment Share on other sites More sharing options...
Jowzer Posted February 28, 2006 Share Posted February 28, 2006 Nice one OT1..will try it out asap! Thank you Link to comment Share on other sites More sharing options...
oldtimer1 Posted February 28, 2006 Author Share Posted February 28, 2006 Josser/All as a note:- The advise above on overriding a fan speed controller with a thermostat to deal with high temperature is valid as far as it goes, in that it shows continuity of live, earth and neutral conductors. To be totally safe all terminations should be in enclosed boxes, all cables retained to the enclosures/boxes with restraining clamps. Where the circuit becomes more complex it is easier to just show just the live path connections as a circuit diagram. All the diagrams are for your understanding on how it works, not a guide to wiring the circuit. Under uk law it is illegal to wire and connect electrical circuits of this type unless first checked and approved by a certified electrician. Link to comment Share on other sites More sharing options...
Jowzer Posted February 28, 2006 Share Posted February 28, 2006 (edited) Understood.... (Ot1 imagines being blamed for jozzers growroom burning to the ground) Cant find any mains changover relay's tho...is there such a thing or will i need to use a transformer to 12v? Have a handy electronics engineer who can check it out for me...I been waiting for him to do this for me for a year....better to do it myself then invite him to criticise it Edited February 28, 2006 by Jozzer Link to comment Share on other sites More sharing options...
oldtimer1 Posted February 28, 2006 Author Share Posted February 28, 2006 Jozzer we are in a time where its going to be illegal to wire a 13a plug soon. I'm retired so no longer qualified to advise, or so nanny state says. You can get mains coil octal based relays such as omron, schrak etc from radio spares maplin etc all you need is a octal base, a plugin relay and a cover plate so you don't put your pinkies on a live terminal. See pic:- Diagram for low medium preset and full speed via thermostat:- Diagram for low medium and high preset via thermostat:- I hope this helps you in your quest. Link to comment Share on other sites More sharing options...
Jowzer Posted February 28, 2006 Share Posted February 28, 2006 Very elegant solutions. I wish I had asked last year now!! Will get on it imediatly....fed up of going to adjust the fan myself twice a day Thanks! Link to comment Share on other sites More sharing options...
OCC Posted February 28, 2006 Share Posted February 28, 2006 Thanks for the new diagram ot1. I think though am I right in thinking that the fan controller will be trying to vary the power going to the thermostat this way? Doesn't seem to like it. Cheers Link to comment Share on other sites More sharing options...
oldtimer1 Posted February 28, 2006 Author Share Posted February 28, 2006 From your diagram and your description the habistat acts as a double pole switch disconnecting live and neutral power out. I show a constant live and neutral to the habistat just as it has always been connected. The switched neutral on power out should not be connected. The switched live power out overrides the dimmer when in the make position. ie it connects the two dimmer contacts together. Its important that the mains in and the power out wires are connected the right way round. If you have wired it as I showed it, what is not working as it should, ie what exactly is it doing? Link to comment Share on other sites More sharing options...
OCC Posted February 28, 2006 Share Posted February 28, 2006 (edited) Well the Fan seems to just come on full power with the speed controller turned off and it has no effect. Somehow power is getting to the fan but I have no idea how. All that is connected to the fan power wise is the L1 and a neutral that is coming stright from the mains. Somehow and for some reason the Habistat power out is giving the fan power even when the thermostat is not active (it has lights to show Device On). Only thing I can see is does it not create a live loop between the Mains in of the Habistat and the Power out? i.e Habistat Mains in is indirectly connected to the Habistat Power out. Or does this not matter? Thanks for your help Edited February 28, 2006 by OCC Link to comment Share on other sites More sharing options...
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