Custom controller under test (Finally)

[Snowy Rivers]

As many of you know I designed a complete stand alone controller for my Whitfield Prodigy 2

This has been an ongoing thing, and due to some parts sourcing issues and my decision to change some stuff around a bit any real serious testing had peen postponed.

I had the time and got after it.

The latch out relay was a bone of contention that I was not willing to concede.

I was adamant about having a way to prevent a restart in the event of a power outage without pressing a reset button.

Finally I was able to figure out how to use a one shot timer as a latchout.

Simply leaving the resistor terminals on the cube open (infinite resistance) keeps the unit latched until such time as power to the power cord is lost.

Soooo
Ordered up the one shot timer (using as a latch relay) last spring and it came and ended up on the shelf for the summer.

I got after this project a day or so ago and set it all up for a good test cycle.

Wired up 3 LED LIGHTS to use for testing.

Test one
Does the latch out work?? YESSSSSSSS IT DOES
Does the main circuit turn on the draft fan ?? Yes it does
Does the Triac control operate the convection fan ?? Yesss it does
Does the cycle timer (Burner control) cycle the feed motor at 10, 8 and 5 second intervals when selected

YESSSSSSS IT DOES

Here are some pix of the "mock up" in operation

The Far right lamp is simulating the DRAFT FAN
The center lamp is simulating the CONVECTION FAN (Dim in some pix)
The left lamp is simulating the AUGER MOTOR. (Blinks on and off)

Absolutely marvelous so far.

It's been running now for several hours, so I pulled the plug and then plugged it back in, NO POWER, the reset had to be pressed to get things working again (That's the plan)


The timer circuit seems stable, although I do need to adjust the ON TIME a tiny bit.
I want 2 seconds feed time and its about 1.5 now.

Will need to tweak the adjustment on the timer a tad.

Very pleased with the design and operation.

All off the shelf stuff that will run most pellets stoves that do not use auto light.

Manually adjustable convection fan, and 3 heat ranges.

Manual cool down with a burner (auger) on off switch.
Main switch that powers the draft fan when on and then powers the remainder of the unit

A link to one of the original threads
https://www.hearth.com/talk/posts/1802595/

https://www.hearth.com/talk/posts/1868707/

 

[jintoreedwine]

This is a really sweet project! Hope your first burn goes well when you convince yourself that things are working as planned .

 

[Snowy Rivers]

Thanks

The controller is built with mosfet type solid state relays of a 10 amp rating.

None of the components draws anywhere near that much current.
The draft fan, convection fan and auger motor all all fused at 2 amps (Separate fuses) and the main is at 7 amps

These timers are rated at 100,000,000 cycles. Ahhh that should last a while

Actually, the timer that controls the on and off time on the auger motor has a rating of "Unlimited"
The one shot I am using as a latch out is rated at 100,000,000 or more cycles, but will see a limited amount as it only cycles if the power is lost. (We will likely unplug stove during off season)

I really don't see any issues here.
This stuff is heavy duty industrial components, so they should last forever (Fingers crossed)

The heavy rubber covered cable used to connect the panel to the stove is 16 gauge wire 12 conductor
Talk about overkill.

The next plan is to Duplicate the controller for the Big Whitfield

I have plenty of heavy cable.

I will make the transfer to the new controller when time and low need of the stove presents itself.

Having it ready is a plus, especially when winter is on the door step.

It would take minimal time to plug the new system into the stove.

I will likely abandon in place the old controller, and just mark the leads and tie them up to keep them out of the way.

The stove is such an integral part of our multi stove approach to heating around here.

We have two Whits and a Quad and when winter hits it is nice to have a spare.

We usually use the Whits, but if we get an Arctic blast the third one is nice to have.

Or if we have one down.

Just wanted to share.

 

[Wilbur Feral]

Awesome work, Snowy. Always enjoy reading about your projects. Thank you for sharing.

 

[Don2222]

Wow - good job!
How about a remote control?

I just repainted a Sept 1990 Prodigy II after I figured out where to plug in the booster fan! It really throws out the heat!

Can you explain how the combination convection/exhaust blower works?

 

[Snowy Rivers]

Hi

The Prodigy 2 uses a draft booster in the top housing to help get the smoke drawn out of the fire pot, plus the convection fan blows into the heated air plenum and there is a small shunt tube that directs a small amount of pressurized air into the fire pot.

The Prodigy 1 did not have the booster in the top casting and WAS REQUIRED to use a tall chimney, and could not be direct vented.

The P2 can be direct vented (Mine is a direct vent)

Snowy

 

[Snowy Rivers]

I don't know of any other stoves that use the convection fan to aid combustion

 

[Don2222]

Thanks Snowy!
So it basically has small positive draft into the burn pot and a larger negative draft fan just like the super modern Osburn 5000 and 7000 pellet stoves!

It is just amazing how much heat comes out of that little stove!

Did you have the updated relay module?

 

[Snowy Rivers]

That's about it.

The original prodigy went through some teething issues early on.

The first ones were IFFY

The P1 was very dependent on a good flue draft to get combustion going and keep it so.
The next thing they did was add a secondary air pipe in the fire box to help keep the combustion good.

The controls were changed as well

Some units had a different control board as well

The later ones were fitted with the top mounted draft fan, and this really allowed the little stove to work well.

The SSAC control board was a vast improvement over the older ones with the ICM boards

The one thing I don't like is the convoluted arrangement that runs the draft fan.
The original set up required the door switch to be activated to get the draft fan going.

This makes starting the stove with a propane torch a real pita.

A quick poke at the door switch with the heat setting on 3 will get the draft fan on, but its fussy.

My system turns on the draft fan as soon as power is switched on.
The low temp switch was only used to shut the stove off.

You would turn the switch off and the draft fan would stay on until the fire was out and the snap switch cooled and then shut off the fan.

The low temp switch had nothing to do with the feed system or start up temperature.

I eliminated the snap on the low side as it was worthless.

I ran the main power through the high limits (2 in series) and replaced them with manual reset type.

This keeps thing even safer than factory, as the snaps , if tripped, must be reset manually.

The auger wiring still goes through the pressure switch and the door switch controls the convection blower circuit to prevent ashes etc from being blown out if the door is opened.

The original setup was a tad sketchy as far as design goes.

Buttttttttttt, it worked OK

The Prodigy 1 and 2 never really were a popular stove for some reason.

Size maybe ????

 

[Snowy Rivers]

Custom controller has been testing now all day yesterday, through the night and is going right along.

I have a feed motor and a couple fans that i can now plug into the harness and see run them real time rather than light bulbs.

This will give us different test parameters and load the circuits a tad more.

Will get pix of that setup when I get it mocked up.

I want a good test run before putting my stamp of approval on the beast.

Snowy

 

[Stovensen]

Thanks for sharing, Snowy! Excellent job and very encouraging for us owners of older Whits ( and other stove brands ). If our control boards "go south", you have shown us how to work around this.
I understand that you are using a Triac fan control to tweek the fan speed. The very first Advantage I series had a rheostat to control the fan speed. And I believe that the Whitfield Legend also had rheostat fan control. What are your considerations on Triac control versus rheostat control?

 

[Snowy Rivers]

These were actually a triac being used.

A true rheostat varies voltage and this is a quick way to burn up the motor.

I am using a fan speed controller, which is a triac.

The white knob on my panel is the fan speed controller.
It is a top quality CASABLANCA FAN speed control is all.

If you get a speed controller and the fan make a funny whining or "harmonic" noise, then the triac is a POS
Whats happening is the triac is not getting the portion of the wave equal on both sides, or is using a portion that is a different length or position in the wave.

Sort of a wha wha wha sound.
Anoying as hell when your trying to watch TV



Sort of like flipping a light switch on and off real fast (Sort of)

The motor gets the full voltage, just not for very long depending on the setting.

 

[Stovensen]

Snowy, thanks for sharing your experience with us. Actually, that whining noise from the convection motor was an issue for me in the beginning. You could hear it in all rooms The motor control on the board has five settings and the noise was worst on the #3 setting, the one we use the most.

I found the solution to this issue in a small notice on page 7 in the original owners manual:

Your Casablanca fan control can be varied stepless, right? Very good feature... this enables you to fine tune the speed and thus eliminating the whining noise.

Yes, manuals may have some hidden goodies, if we only would take our time to read them in detail.
RTFM, as they say

Looking forward to hear about the progress of your Prodigy custom control.

Cheers,
Bo

 

[the3dprinterman]

Nice Snowy! I don't know if you ever heard of EZAutomation, but they are advertising a new timer that might interest you. http://www.ezautomation.net/emails/EZTimer/EZTimer2.html
The same time can be used as a single shot, a cycling timer, and delay timers. Have a peek.

 

[Snowy Rivers]

The fan motors should not whine at any point in the control range of the triac, but, as they say, THE BEST LAID PLANS ya know ???

The more $$$$ spent on the triac (larger components ** better quality) the less apt they are to cause harmonics to set up.

The fact that the builder added the trim pot tells me that they knew there was an issue and they had the forethought to remedy it so they would not be chasing Eldorado on some units.

Some fan motors may be more susceptible to the harmonics than others.

Nice that you could remedy the noise.

It's sure anoying when it gets in the UGLY spot.

Printerman

Those timers are relay type plug in units, and likely are a mechanical timer with a solid state control system.

The units I have are a 2 inch square Totally solid state unit.

The timers have an unlimited duty cycle whereas the mechanical units have a finite amount of cycles before they wear out.

The Mosfet type units are really sweet.

They can be spec'd out as to what voltage (120v for stove app) What amperage (5 10 15 ) on time adjustable on board the timer or remote pot and even fixed if you desire.

The off time can be had the same way.

I ordered the timers with the on time on board with a a local pot, and the off time (Heat range in the case of stoves) is controlled by a remote pot, or as I did it a fixed resistor pack that gives the required time delay for the chosen delays (5 sec, 8 sec, 10 sec )

I could have used a variable pot, but decided to go with set LOW MED HIGH to avoid a mishap with the setting getting bumped easily.

Getting the Solid state timers is not hard, just some companies will not build them unless you want a metric buttload of them, or at least not at an affordable price..

I originally looked at the plug in timers, but was discouraged from that route by the head engineer over at precision timer co.

He directed me to the 646B series timer.

120 Volt, 10 amp, .1 to 5 sec on time (on board adjst) .1 to 10 sec off time (remote) (Heat range)

They have just about any combination available.

I used ranges that were very similar to what the original stove controls had to make life simple.

It made no sense to spec out a timer with far and away excess range capacity.

Most stoves do not exceed 2 seconds feed time so the .1 to 5 was perfect and the same with the off time (burn) the 10 second off just about runs the fire out.

If the fire dies out a tad too far I can bump the on time up a bit to feed just a bit more on each cycle, and if there is an issue, I can tweak the booster fan speed a bit too.

All sorts of great and fun stuff.

 

[Snowy Rivers]

Test phase two

Phase 1 of testing is complete and now we have real motors and fans connected to move into phase 2

All systems operating normally at this time.

The draft fan operates at full speed (line voltage)
Feed motor cycles normally
Convection fan operates smoothly through the entire speed range with no appreciable harmonics in the sweet spots

When phase two is complete here in a few days of operating, the new controller will be ready to "Gitterdone"

 

[Snowy Rivers]

Been operating smoothly all day with the two fans and the feed motor connected.

Varied the convection fan up and down, moved the feed from high to medium to low and back again.

So far all seems no different than with the lamps hooked up.

Will test off and on a few more days, then pack up the test gear and call it good.

At this point I don't think there is really any issues.

 

[Kennyz]

Good on ya mate!

 

[Snowy Rivers]

Thanks

Just what I do.

Was a machinist, welder, fabricator, electrician for a big company for years.

Served as a field service engineer.

 

[Snowy Rivers]

Everything seems fine with no issues at all.

The one component that could have issues would be the timer for the on / off cycle, but these very same timers were sold to pellet stove manufactures for many years before the companies all went to proprietary control boards made over seas, soooooooooooooo, there is really no worries.

Time to call it all GOOD.

Happy to have the panel complete and tested.
If need be the new unit can be plugged into the stove in a matter of an hour or less.

Time now to start building a similar unit for the Advantage 2T we have in the family room.

Going to use a brushed aluminum panel (Same style) and will use the same components other than this time we will add a start up timer with the low temp switch in the circuit.

The main reason is that the Advantage 2T came with the start circuit and I want to keep all safety devices originally in the unit.

I am likely going to change out the snap switches and install the manual reset type.
Running primary power through the snaps allows for complete shut down in the event of an over temp situation and having manual resets keeps a restart without intervention out of the question.

I am even toying with the idea of a snap over temp switch on the vent.

Ahhh yesss

Snowy