thermostat adapter for minisplit??

I have a pioneer 18000 btu mini split ac for my sealed room and was wondering if anyone had any experience with wiring in an external thermostat adapter for these units. It only has a timer function and its really starting to eat up alot of energy running it constantly .when i bought it i wasnt aware they had no internal thermostat to switch on and off. Im guessing there has to be some way to wire in a switchable power source thats triggered by the thermostat. The unit has auto restart on power failure. Any help would be appreciated.
Thanks

Definitely doable
Inside the unit there is most likely a contactor or relay that is energized by the timer on the unit, which causes the contacts on the contactor to close, allowing power through to the unit compressor and fan, the unit thus turns on. when the signal from the timer turns off, contacts open, no power can get through, unit turns off.

What you'll ultimately need to do is remove the wiring that goes from the timer to the contactor's coil, and replace it with wire coming from your new thermostat, so that it operates the contactor instead of the timer.

The first thing you'll need to do is find out what the coil rating is on the contactor. Open up the unit and on the back of the timer will be wires. They will most likely go to a small box like 2x2 inches square or thereabouts, the box will have wires going to the compressor and fan(s). This box is the contactor or relay. It is the "bridge" between your timer or thermostat and power going to the unit. It connects the two. There should be two separate ratings on it. One will usually be a chart with voltage and FLA (Full Load Amperage), this is not what you are after. This rating is for the power poles, not the coil. You want the coil voltage.
There should be a rating that mentions only voltage, and it should specifically say "coil voltage" or perhaps just "coil".

If the coil rating is 120v it would be easy to then buy something like an STC-1000 controller off youtube, and for $50-$75 and an hour or 2 of work you'd have a digital controller with pretty flexible programming options, even has adjustable compressor restart protection so your a/c isn;t going on/of on/off every 3 minutes, which is hard on compressors. If it's a low voltage coil, 24v or 12v it is still doable, just a tad more complicated, will need to talk more options in that case.

Let me know if you can find that, I'd be glad to help you get this set up.

Ok so timer will become the switchable source power wire im assuming and id need to run it in timer mode? Not sure if that will receive power if timer mode is not activated id have to check with a multimeter. Its a 220 vac system i will try to do some research on the schematics of the unit to check the coil. . I had been in contact with someone that makes these controllers but it would end up being 300$ for what is essentially a makeshift relay. Jp manufacturimg i think was the name. Im gonna see if i can figure it out tonight and post what the coil is. I reallly appreciate the help. This has been plagueing my energy bill.

This is on the condenser

This is the manual for the unit

I would check the controller.
according to the description.....

WYQ is the most Efficient INVERTER model in the Pioneer model line up. Included wireless remote controller allowing the users easily select among the 4 operating modes; Cooling, Heating, Dehumidification and Ventilation. Additionally an automatic switchover mode is available for totally automatic operation through its on board computer. A timer function allows the user to set the system to start or stop running at a certain time. Night mode function automatically adops the temperature settings to the human body's naturally changing temperature levels during the night. Auto restart function memorizes all settings in case of a temporary power failure and restarts the system to continue running the same way after the power is reconnected. Last but not the least, an automatic swing discharge air louver gently changes the direction of the air flow in a sweeping action for total comfort.

This is the other manual i found its the wyd series. These units dont turn on and off based on temperature they just run at a constant temperature. They never turn off.

Yes so you can see in the outdoor wiring diagram there is a contactor. In your model there is also a relay in the indoor part of the unit.
Unfortunately I don't see anything about the coil voltage of the contactor, and the transformer doesn't say what it steps the control voltage down to either.

Looks like you'll need to take a look in the outdoor unit for the coil rating of that contactor.
The instructions state the voltage between 1, 2 and 3 which are the 3 control wires and L2 should be 208-230v so since 1 goes to the contactor coil, I'd assume the coil voltage is 208-240v. But it'd be best to check on the contactor itself to make sure, so many different models they may have some errors in the manuals.

Perhaps something like this?
http://www.aliexpress.com/item/AC-220V-30A-Micro-Intelligent-Thermostatic-Switch-60-125-Celsius-Degrees-Digital-Thermostat-Temperature-Controller/2020875984.html

kcc420 said:

Ok so timer will become the switchable source power wire im assuming and id need to run it in timer mode? Not sure if that will receive power if timer mode is not activated id have to check with a multimeter. Its a 220 vac system i will try to do some research on the schematics of the unit to check the coil. . I had been in contact with someone that makes these controllers but it would end up being 300$ for what is essentially a makeshift relay. Jp manufacturimg i think was the name. Im gonna see if i can figure it out tonight and post what the coil is. I reallly appreciate the help. This has been plagueing my energy bill.

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Yeah, Grandpapy makes a good point you could probably find something like what he linked or
http://www.horticulturesource.com/hydrofarm-digital-cooling-thermostat-p17721/
but in 240v. Not sure where but I am sure on the net somewhere 50-100 bucks. But I imagine your unit is hardwired to a breaker in your panel, it doesn't simply plug in does it?

The way I first suggested ( to answer your question which i missed before) would bypass the timer module completely and the STC-1000 or whatever you use for the controller would turn the unit on and off itself based on the on and off temperatures you program into it.

I have a question. I'm looking into buying a Mitsubishi or Goodman mini split. I was told that if needed, I would have to switch modes from ac when the lights are on to heat when lights off. I'm going to assume that that digital cooling thermostat wouldn't be what I would need for the unit to automatically make the switch? This has been on my mind for a while and I would appreciate anyone who could chime in. I deal with cold cold winters and hot hot summers.

I have a Gree Terra 24000btu... It has a thermostat on the head unit, also the remote control can be used as a thermostat... I didnt realize that this could be such a problem?

They all read return air temps and cool until they reach the temp you set. You might just try running it on the "Dry" setting which will leave it at low fan speed all the time. The down side to mini splits is when you over size them they tend to make humidity issues worse by running all the time but just barely "working" which reduces their capacity to remove latent heat(the moisture part) .

shloppyjoe said:

I have a question. I'm looking into buying a Mitsubishi or Goodman mini split. I was told that if needed, I would have to switch modes from ac when the lights are on to heat when lights off. I'm going to assume that that digital cooling thermostat wouldn't be what I would need for the unit to automatically make the switch? This has been on my mind for a while and I would appreciate anyone who could chime in. I deal with cold cold winters and hot hot summers.

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Yeah, The STC 1000 has 2 separate relays 1 for heat and 1 for cool, so it would allow you to bypass or modify the existing control circuit on the unit and use the controller to power the contactor for the compressor & fan for cool and also the contactor for the heating. you would need to look at the wiring diagram for the specific unit to know exactly how to wire it, depends on the coil voltage of the contactor if its 120v it's easier than if its low voltage. The heat and cool relays on the STC are 10 amps each which is more than enough to power the coil on the contactor(s). The STC is only sending a signal to the contactor it does not actually see any of the power drawn by the A/C, it only provides enough power, probably 0.5 amps or less to the magnetic coil of the contactor which when energized closes the power poles on the contactor, allowing power to flow through the contactor. The contactors bear the load of the unit.
It's been a while since I've programmed these controllers but if I remember correctly if you set a setpoint of say 22.5 degrees C, then set the difference setting to say 2.5 degrees C. When temps hit 25 it will cool, when temps fall below 20 it will heat. It has a compressor protection timer built in 1-10 minutes so it doesn't turn on and off every 2 minutes.

The Goodman' are Daikin so you could use the envi thermostat and just program whatever schedule or mode you want to use via the t-stat or your laptop /smart phone.

If it is only on and off why not get yourself a 240 volt contactor and a 240-24v transformer and a thermostat, wire the unit to the contactor with external power coming in from the breaker or disconnect, Use the transformer to supply 24 volt power to the thermostat. Switch your unit to always on. The contactor will cut power to the unit til the thermostat calls for cooling which will trigger the contactor and supply power to the unit. It will take a few minutes for the unit to power up but it should go back to the last setting before the power was cut (ON cooling cycle). When the stat is fulfilled it will cut power via the contactor to the unit. I think that would be the easiest way without having to get into the guts of the unit and rewire it. This can work for most units except daikin which comes back on in the off mode and fujitsu which requires a dc fan for the condenser. Takes a lot more rewire for those units.

herballuvmonkey said:

If it is only on and off why not get yourself a 240 volt contactor and a 240-24v transformer and a thermostat, wire the unit to the contactor with external power coming in from the breaker or disconnect, Use the transformer to supply 24 volt power to the thermostat. Switch your unit to always on. The contactor will cut power to the unit til the thermostat calls for cooling which will trigger the contactor and supply power to the unit. It will take a few minutes for the unit to power up but it should go back to the last setting before the power was cut (ON cooling cycle). When the stat is fulfilled it will cut power via the contactor to the unit. I think that would be the easiest way without having to get into the guts of the unit and rewire it. This can work for most units except daikin which comes back on in the off mode and fujitsu which requires a dc fan for the condenser. Takes a lot more rewire for those units.

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Good idea herbal. That'd work just fine too, OP. Same principle but you just add a contactor into the wire that feeds the unit, instead of using the one already in the unit. This would be easier to DIY than my idea so long as you have decent access to the wire.
You could also still use a 120v thermostat like the STC 1000, just need a 120v coil contactor instead of the 24v coil for herbal's idea. You could wire a male plug end to the STC 1000 and plug it into a 120v outlet and avoid the need for a transformer. You could also then hook up a heater to another contactor off the same STC 1000 if heat is something you desire in the winter.

If you can find an electrical supplier that does fair prices for cash sales this wouldn't cost much for materials. Around $100-$150 if their prices are fair.

Isn't this all you need? I got it at Home Depot for around $70. It will switch between heating and cooling, allowing you to set temp. ranges for night and day. http://www.homedepot.com/p/Honeywell-5-1-1-Day-Programmable-Thermostat-with-Backlight-RTH6450D/202491353

nevergoodenuf said:

Isn't this all you need? I got it at Home Depot for around $70. It will switch between heating and cooling, allowing you to set temp. ranges for night and day. http://www.homedepot.com/p/Honeywell-5-1-1-Day-Programmable-Thermostat-with-Backlight-RTH6450D/202491353

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Any tstat would work so long as it's output voltage is the same as the coil voltage of the contactor being used to power the a/c unit. if it isn't the same voltage a transformer can be added to step the voltage up or down to the desired amount.

You can get an adapter that works for all mini split systems that allows you to connect any thermostat you want to your mini split system. You can even control your system from anywhere using your smart phone. Minisplitcontroladapters.com
Is the site that has them.