Hey Al,

Great find!

Can you see a brand name or a model number or something on this? Or is it that Jaycar manufactures this one themselves?

Thanks.

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Handy little beggar.

The brand name is "Computime" model number is 098A.




I have also seen the same thermostat on a Romanian website under the brand name 'Computherm' also with model number 098A. Handy for the next time you're in Romania.

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How not to grow dope - 'Not Your Father's Marijuana' / 'new super cannabis' / 'extra potent hydro' myths busted
DIY batwing reflector - DIY power panel to keep electrics safe and neat - DIY low-temp 3-day bud dryer - Get a harvest every 2 weeks - Photoessay: A batch of clones in rockwool - Project Big Blue Bastard: DIY 5-tube, 100 watt UV ioniser

...and don't even THINK about asking me how to hide your grow from your MOM. This is an adult sport. Give it up until you grow up.

Okay...
So the thermostat has to be for line voltage , correct?
Sorry I'm a little confused about wiring these.
Do I take apart the thermostat and re-wire it to use the other set of contacts on the relay? Or, do I connect the thermostat straight to the fan?
Could you please explain?
Thanks again.

yep

Use the thermostat as you would use any switch.

Break either the line or neutral wire in the power lead going to the fan. Connect the thermostat's contacts at the break.

I like to wire thermostats into extension cords. Makes it very easy to replace the fan in future.






Just unplug the old fan and plug in a new one.

__________________
How not to grow dope - 'Not Your Father's Marijuana' / 'new super cannabis' / 'extra potent hydro' myths busted
DIY batwing reflector - DIY power panel to keep electrics safe and neat - DIY low-temp 3-day bud dryer - Get a harvest every 2 weeks - Photoessay: A batch of clones in rockwool - Project Big Blue Bastard: DIY 5-tube, 100 watt UV ioniser

...and don't even THINK about asking me how to hide your grow from your MOM. This is an adult sport. Give it up until you grow up.

Awesome...Mine says it has a Triac Silent switching relay,
Would this matter? Do most thermostats have both sets of contacts? My model is a Honeywell digital non-programmable for baseboards and convectors. Its say 3000w @ 240v @ 12.5 amps.
What is the difference between this and your "reversing the thermostat logic"
thread.
I usually try to figure this stuff out myself but I don't wanna open the packaging until I'm sure...
Thanks very much for your help...much appreciated.

I've opened the package...
I think I may have the wrong thermostat
The exact model is Honeywell RLV3100A
This thermostat cannot be used with the following:
-resistive load under 2A
-resistive load over 12 A
-systems driven by a contactor or a relay(inductive load)
-fan-forced heating systems
-central heating systems

Will this still work?

Yep, unfortunately.

And that's why. This thermostat uses a solid-state switching device known as a triac instead of relay contacts. A triac is essentially just a big transistor. They're used because they don't go KLIKK every time they switch. Downside is that to keep the current flowing properly in them, there's a minimum current rating. 2A @ 240V is 480W. Only the very largest blowers will come close to drawing that amount of power.

Sorry, no- it won't.

Swap it out for a unit with a relay. Chances are, your blower will draw 1A or less if you're on 240V.

When I discuss 'reversing the logic of a thermostat', I'm talking about making a thermostat intended for a heating appliance suitable for a cooling fan. A heating thermostat switches on (contacts close) when the temp falls below the setpoint. A cooling thermostat switches on (contacts close) when temps rise above the setpoint.

If for example, you have something in your junkbox like an old thermostat for a waterbed, it can be used to turn a relay on and off which can switch a fan motor. The relay you select from Ye Olde Electronics Junque Shoppe can have both normally open (NO) and normally closed (NC) or just NC contacts.

In practise, the heating thermostat's contacts will open above the setpoint, opposite of what you need for a cooling fan. Use the heating thermostat's contacts to switch a supply voltage to the coil of a SPST (single pole, single throw) NC relay. You can use DPST or 4PST relays as well, but you'll only need one pair of NC contacts. All you need is a pair of contacts that are connected when the relay coil is not energised.

You have to come up with some sort of power supply to operate the relay's coil. An old plugpak power supply or battery charger will do fine. Just match the supply voltage to the relay coil voltage.

The waterbed thermostat switches off at and above the setpoint, removing the voltage to the relay, so the relay's NC contacts will close. Use that set of NC contacts to switch your cooling fan. When the temp is below the setpoint, the heating thermostat's contacts will close, completing the circuit from the power supply to the relay coil, opening the NC contacts.

Seems complex, donit? It is, a bit. However, this is exactly what has allowed me to use an old waterbed thermostat to run my flowering area's exhaust system for the last 8 years or so.

That's why I like the little Computime thermostat so much. Makes the task cheap, simple and reliable. No external power supply nor wiring needed. Has both NC & NO contacts so it can work for heating or cooling. Bang, $40, done.

__________________
How not to grow dope - 'Not Your Father's Marijuana' / 'new super cannabis' / 'extra potent hydro' myths busted
DIY batwing reflector - DIY power panel to keep electrics safe and neat - DIY low-temp 3-day bud dryer - Get a harvest every 2 weeks - Photoessay: A batch of clones in rockwool - Project Big Blue Bastard: DIY 5-tube, 100 watt UV ioniser

...and don't even THINK about asking me how to hide your grow from your MOM. This is an adult sport. Give it up until you grow up.

Thanks...I guess it's back to home depot...damn...thought it was too good of a deal for 29 bucks

You know, I might have bought one, if I had not read the fine print. Not all triac switching devices have such a high minimum current- so it happens, the one you picked up was suited also for switching a 3000W resistive load (12.5A@240V). That's a big fucking triac.

There certainly are triacs around suited for switching low currents (200mA). The tstat you found was intended for direct control of a big resistive load and thus had a triac much gruntier than you need for a blower fan.

__________________
How not to grow dope - 'Not Your Father's Marijuana' / 'new super cannabis' / 'extra potent hydro' myths busted
DIY batwing reflector - DIY power panel to keep electrics safe and neat - DIY low-temp 3-day bud dryer - Get a harvest every 2 weeks - Photoessay: A batch of clones in rockwool - Project Big Blue Bastard: DIY 5-tube, 100 watt UV ioniser

...and don't even THINK about asking me how to hide your grow from your MOM. This is an adult sport. Give it up until you grow up.

Hey al, I want to set up a Thermostat for my room.

I want it to be a programmable kind so I can set what temp to run at night and during the day.

I would like it to be hooked to the air conditioner as well as a Heater.

The heater is around 1500 watts 12.5 amps on 120v
The air conditioner is 8000 btu. cant find the wattage/amps

I am not super savy on how to accomplish this, but I understand basic wiring directions, ect...

any chance I get some basic help on how to accomplish this.

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