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build a thermostat controlled fan speed unit


Detritus

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thanks yet again guys - just off to order those extra bits now!

Sorry OT, I meant that I need to use one transistor and diode per relay. I won't embarass myself by asking what HVAC is. oops.

Mad - I know what you mean, I was expecting some kind of mighty tome telling me all sorts of interesting things I could do with the temp module - a bit surprised when it turned out to be a tiny leaflet! still, if it does what it says it does then it's going to be bloody brilliant!

cheers,

Det

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Guys,

I've done two wiring diagrams: one for connecting the relays to the fan controller and the other for wiring the module to the relays and various switches (I've added a couple of LEDs to show what speed the fan is running at). Would you mind having a look at them for me?

The switches for pins 5,11,14 will be sub-mini toggle type E (on-on) part ref FH04E at maplins £1.49 each

The switches for pins 2,3,12,13 will be sub-mini toggle type H((on)-off(on)) part ref FH07H at maplins £1.49 each.

The LEDs will be 5mm Green 12V SuperBright LEDs part ref CJ62S £0.29 each

The thing I'm stuck on is what type of wire should I use for the connections? - once I know this I can order the final bits and build this thing!

The maximum load on the fan circuit (240v AC) is when the fan and radiator are on (when the temp is below the lower limit).

radiator draws 2.92A (700w/240V)

The fan draws 0.5A (from rvk.pdf)

so the voltage is 240 and the maximum current is 3.42A. What wire does this mean I need?

The maximum load on the temp module circuit will be from the relay coils (part ref QC58N) which have a resistance of 140ohms - I think this means they draw a current of 0.09A (I=V/R => 12/140)? so what wire do I need for this circuit?

help me Obi-Wan, you're my only hope!

Det

post-102-1065904379_thumb.jpg

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Blimey, a new subject heading! What a great idea.

Anyways, heres the other wiring diagram - for the fan circuit. It's basically a rehash of OT's preivous diagram but with the relays instead of the thermostats.

post-102-1065904974_thumb.jpg

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On a side note, I've found what seems to be quite a good Electronics Tutorial- but then I don't know much about electronics!

I'm gonna give some of the experiments a go though I think - I'm really enjoying learning about electronics - I haven't done any since school 12 years ago. We didn't do any in my Programming degree either which was disappointing, I was hoping to construc some logic circuits or something.

any ideas on that wire guys - I'm itching to order!!!!!! lol

Det

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Great a bodge it yerself section lol

any way Detritus ive attached a circuit diagram of the power supply,hope it helps,also are those leds the correct way around lol

wire size,for the low voltage stuff (relay coils ect) pm me an adress if ya want and i can send you a couple of meters of somthing suitable or something like 2 meters of XS98G just remove the outer sleeve.

finally the second drawing,whats ment to happen when the hi temp alarm is triggered? at the moment it will make a big bang and the lights might go out as its shorting live to neutral lol

post-102-1065913393_thumb.jpg

Edited by Themadhippy
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Detritus I don’t get it, Ot green and cabbage looking.

Are those relays change over or just make an break?

Whatever high relay on should not connect live to neutral, it should go to the common conection from the controlers ie the live fan feed.

Edited to add, hey TMH you beat me to it!

Detritus told you things were changing the whole cannabis cultivation section has had a make over, do you like it?

Edited by oldtimer1
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Detritus I sent this to you last night by PM as I could not post. I'm not sure if you got it as we have been haveing Dbase probs.

Seen another prob, I only added the heater into the circuit because you showed it. It occurs to me the heater has to be live switched separately not common to one side of a controller as the controller is an inline ac devise, otherwise you will get back feed through it when via the heater when the high relay is on. so the low relay relay needs to be a double pole change over.

To add to it, it is important to check that none of the combinations of switching allow any reverse paths to neutral through either of the dimmers.

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Hi guys - sorry about the delay in replying - tried to last night but couldn't as OT tells me there were probs with the site - thought it was me making more stupid mistakes!

Mad - cheers for the circuit diagram mate, I'd just made a complete guess at what you do with the bridge rectifier and smooting capacitor - yours makes a lot more sense!

Thanks for the offer of the wire mate - I ordered 2m of XS98G last night with the rest of the bits I needed. All I need now is to get some wire for the fan/controller/radiator circuit - am I best using normal 3 core flex for this? If so I'll shoot down B&Q tomorrow and grab some.

thanks Mad and OT for pointing out my mistake on the diagram - I was far too stoned to be doing anything yesterday but just couldn't wait! At least by doing wiring diagrams first and getting you old pros to check them for me then my mistakes only cause embarrassment and not fires! :lucky:

OT - thanks for the heads up on needing to have the radiator switched seperately - but I don't understand why - I'll have a look on that tutorial and see what I can find out about feedback. Does it mean that when power goes through the high relay and direct to the fan, some of the electrons will loop round to the heater through the low controller and back to the fan??? complete guess so probably wrong. I'll do some reading before I make myself look stupid(er).

Luckily the relays are both DPDT - I'll use the high alarm relay as a DPST and the low as a DPDT where the radiator one is off when the alarm is off.

OT - I'm sure you couldn't be green and cabbage looking if you tried mate (although that would make for an interesting hobby?). I'd be lost without the expertise of people like you and Mad. Really can't express my appreciation enough.

I'll post the latest versions of the wiring diagrams with your amendments - thanks guys. OT I'll start looking into the possible paths now.

cheers,

Det

post-102-1065983014_thumb.jpg

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I've done the possible paths through the the circuit - it looks ok to me? The only thing I'm not sure about is the heater - do you mean that I would need to put it on a separate circuit alltogether? - this would still be controlled by the relay. I was planning to have the whole controller unti powered by a single plub - there will then be sockets on the controller to plug the fan and radiator into. Will this be ok?

Heres those paths:

HIGH OFF LOW OFF

post-102-1065984068_thumb.jpg

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HIGH ON LOW ON

what do you reckon guys? I'm guessing that you do mean the positive for the radiator would need to be separate. No problem.

cheers guys,

Det

post-102-1065984655_thumb.jpg

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The last can’t happen because high temp is on. Low temp would be off so the low relay would be in its unpowered position, so the default connection would be to the medium controller not the high one.

ie the sensor has only 3 states it cant do high and low on at he same time.

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I included that one just in case. As far as I understand it, the chip in the module compares that current temperature to the low alarm point and high alarm and if it is equal to or below or above the respective alarm point then it will change the output to the relevant pin to high and thus switch the relay. In theory there is nothing to stop you from setting the high alram point below the low alarm point - this would then trigger a ON-ON situation where both relays would be powered - just wanted to check that wouldn't cause a problem (I don't plan to do it - but you know how stoners are - monkey see monkey do!). I hope I've understood what you meant correctly mate!

Do they look ok apart from that? My goodies should come tomorrow so I'll probably be up all night assembling it!

Before we get to that stage though I've got a couple of more questions if you don't mind guys:

1. My TD160 (which I'm wiring up to the circuit to test it while I wait to get my RVK150) has no earth terminal on it - what do I do with the earth pin on the plug? Just not have anything wired to it? I'm planning to test this in my lounge so I'd rather not blow the wall socket up or anything!!! lol

2. I've been thinking about the finishing touches for this(premature I know!) and have thought it would be nice to put it into a box/enclosure of some kind. On the front would be the LCD readout from the temperature module, the 5 switches to operate the module, the knobs for the two fan speed controllers (I'm looking at how easily I can remove the workings of the speed controller from their current facia etc.) and from the bottom/side will be a plug to plug the unit in and then two trailing sockets to plug the fan and radiator in (white for fan and orange for radiator - I've bought colour coordinated plugs aswell!).

Am I right in saying that the box would need to have ventilation slots in it?

And with regards to the temp module circuitry - I would like to mount the relays, diodes, transistors etc onto a board - I've had a look at what they sell on maplins and it's baffling! All I want is some board with hole on to put the legs of the relays etc that I can then solder wires to from the other side - I don't want to etch a circuit or anything like that! What would I use to do this - I saw some stuff called "breadboard" but that seems to have contacts all over it - I literally just want the board with the holes in!

Cheers guys,

Det

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