Controll pellet stove AC fans

Hello, the controller of my pellet stove broke and since it's almost more expensive to buy a new controller than to replace the whole stove, I'm considering to make my own arduino controller.

I know how to controll all the devices using relays, but these 2 fans:

Air ventilation fan:
http://www.tadebioenergy.com/ventilador-tangencial-estufa-pellet

Exhaust fume fan:
http://www.tadebioenergy.com/epages/305499.sf/es_ES/?ObjectPath=/Shops/305499/Products/100200

I've read I need to use TRIACs in order to be detect the zero-crossing to able to controll the fan speed, but I don't even know where to start and what components should I buy for these fans.

Some advice will be appreciated..

Hi,
Tell us more about how the fans used to work..

Did the original system have speed control on both fans? How did they behave>

terryking228:
Hi,
Tell us more about how the fans used to work…

Did the original system have speed control on both fans? How did they behave>

Yes you could control the speed of these 2 motors.

There was a feature in a menu where you could test them and it said like 65v, 85v, 110v, 160v or 220v, and the fans went into different speeds.

The controller of the original stove controlled the fans speed for different functions of the stove; for example, during the start of the stove where the pellets had to start burning because the resistence was on it adjusted the fan to low speed, then it had 5 levels of heating, and in every of those levels it adjusted the fan speed accordingly, and for example it put the exhaust fume fan to the maximum when turning off the stove to make it colder and so on…

Hope this helps

Both those fans look to be shaded pole and as such aren't considered as suitable candidates for speed control, so what the manufacturer is doing is simply reducing their respective supply voltage and "wind" load is effecting speed control due to the motors reduced torque capability. In effect, speed will not be directly related to system voltage.

I really don't see any need for zero crossing power control. A simple PWM trigger to the controlling triac should suffice, though you will have to do some experimentation to get the system feed rates correct.

The exhaust fan is critical to you and your family's safety as when you shut down the heater by switching off the air feed fan the stove will start producing lots of CO (carbon monoxide) due lack of combustion oxygen. The exhaust fan 'sucks' this CO out of the stove, in effect creating a slightly negative pressure within the combustion chamber and so preventing the CO from leaking into the room.

Certified stove controllers might be expensive but what price on a life.

jackrae:
Both those fans look to be shaded pole and as such aren't considered as suitable candidates for speed control, so what the manufacturer is doing is simply reducing their respective supply voltage and "wind" load is effecting speed control due to the motors reduced torque capability. In effect, speed will not be directly related to system voltage.

I really don't see any need for zero crossing power control. A simple PWM trigger to the controlling triac should suffice, though you will have to do some experimentation to get the system feed rates correct.

The exhaust fan is critical to you and your family's safety as when you shut down the heater by switching off the air feed fan the stove will start producing lots of CO (carbon monoxide) due lack of combustion oxygen. The exhaust fan 'sucks' this CO out of the stove, in effect creating a slightly negative pressure within the combustion chamber and so preventing the CO from leaking into the room.

Certified stove controllers might be expensive but what price on a life.

But if I do have in mind that the combustion chamber should always be in a slightly negative pressure if the temperaure on the exhaust is higher than X it should be fine no?

I could also install a CO detector near the stove aswell, and besides, if I'm not wrong, the chimney draft when it's hot (which is usually when it's turned off and CO is generated) also creates negative pressure inside the chamber.

Unsure what you mean by your first paragraph so my answer to your question must be "No"

CO detectors are mandatory for all solid fuel stove installations in UK and you should have one as a prudent precaution.

When you close off the air inlet there is virtually no draft up the chimney hence the very real danger of CO leakage unless you have a proven running exhaust fan. Your existing manufacturer's control system should have a sensor device which verifies the exhaust fan is running and sets off an alarm if it is not. Building a DIY control device for something that could seriously endanger your life just to save some money might not be the wisest decision in the world.

jackrae:
Unsure what you mean by your first paragraph so my answer to your question must be “No”

CO detectors are mandatory for all solid fuel stove installations in UK and you should have one as a prudent precaution.

When you close off the air inlet there is virtually no draft up the chimney hence the very real danger of CO leakage unless you have a proven running exhaust fan. Your existing manufacturer’s control system should have a sensor device which verifies the exhaust fan is running and sets off an alarm if it is not. Building a DIY control device for something that could seriously endanger your life just to save some money might not be the wisest decision in the world.

You are correct, there is an encoder in the exhaust fan that is controlled by the microcontroller.

I’m pretty sure that the microcontroller or other components doesn’t “close” the air inlet. What it does to turn the stove off is to stop the motor of the auger feeding the pellets and turn the exhaust motor to max power to cool the stove down and suck out the CO. So yes, because the air inlet is not closed and air can circulate freely into the stove, there would be some draft up the chimney that it is usually at temps higher than 100ºC when operating. Anyway, with two CO detectors near it as a precaution should be fine.

But yes, cosidering everything, I think it’s too much effort and too many variables to make something as good as the commercial controller, so I might end up just getting a new one and that’s it…

Hi, Aleix,
This reply is not about the Arduino, but it might help you.
Sounds like your pellet stove uses a Micronova control card.
I had the same problem with a card failure and replaced it with a new card, identical in theory, with the original in my boiler (Ferroli Naturfire30).
A word of warning ! The card did NOT work correctly in my boiler as the firmware in EEPROM was not correct for my model of boiler. The firmware is stove manufacturer dependent.
Note that I did not buy the Micronova card from the "official" Ferroli subsidy in Spain as they charge about three times more for the card.
As I could not get any technical support in resolving the the issues and according to various blogs on pelletsboilers, Micronova will not deal directly with a controller card owner, or their distributors, only with stove manufacturers.
I also have my boiler maintained by a "Ferroli approved" maintenence company and they can't solve the issue either or get any helpful information, so for me, it's back to investigating the use of an Arduino.

I have code for pellet burner if you want tell me