PF 100 furnace

Wires all checked out good ... I’m thinking it’s the limit switch telling it it’s over heating and sending in to shut down.

 

Makes sense, and switches are considered a "wear item".

 

I’d say you are exactly right. When I got this furnace he had a timer on it for the fuel auger, and I belieave it was wired wrong. Can I replace the triac on the board? Or does this mean I need a new board?

 

Members have replaced them in the past....I'm guessing it depends on how fried the actual board and traces are.

Maybe Snowy Rivers or jtakeman can chime in. Pics of the board will probably help them a lot, to help you out.

 

If someone has messed with it there was likely an issue.

The timer on the auger sounds like a work around to get things operating.

Here is a link to the manual on the PF100 http://downloads.hearthnhome.com/installManuals/PF100.pdf

Also a piccy of the board...
What needs to happen is to look at the schematic (In the manual) and check out all the various components to be sure all the wiring is as it should be.

Note....
The manufacture is not going to show the board schematic and what components they used.


Be sure that the 120 volt outlet is wired correctly BLACK WIRE TO L1 and the White to the Neutral and green or bare to the ground prong.

Use your VOM to be sure that the leads are phased correctly too.

Set VOM to AC voltage scale (High enough to check the 120 volt) check between the WHITE wire and the ground READING SHOULD BE 0
Check between the White and the black wires....reading should be between 115 and 120 volts

If the L1 and the Neutral have been switched it can foul up the controls.


If things check out then it sounds like the control board is HINKY.

Everything that happens has it's origins at the board.

As mentioned..."Possibly the triac has gone south" there are probably more than one on the board..... There is likely a logic chip on the board as well.


As mentioned.....A GOOD SURGE PROTECTOR
The micro electronics are delicate.

Someone may have run this unit using a small generator during an outage.

Many small gen sets produces DIRTY POWER (Poor wave form, cycles above or below nominal, voltage can be high or low)

From what I have seen with small gen sets its usually the wave form is poor.

Instead of a nice even wave (Like power company produces) the wave can have spikes, some are square wave...the upper and lower forms (Looking at things on a scope) are unequal

The small components just can't hack this stuff.

A brown out can mess stuff up...as voltage drops the amperage goes up....

At this point there is really no way to know what the unit was subjected to..

HOW OLD IS THE UNIT ????

If a power surge was the cause the damage can be cumulative. (Been hit more than once)

Also STATIC DISCHARGE can wreak havoc with the micro electronics....

Cold dry weather and somebody reaches in and touches the control knob/s "Snap" a static discharge....

 

Ive no idea why someone might put a timer on the auger.....
The triac being shot will normally not be evident on visually inspecting the board, and operation would depend on what position the triac was killed in. Often see the triac stuck where the igniter never goes off......a wire might get pinched, or insulation might get burned off, etc. If the stove was in an ignition cycle when it died, the triac will keep the igniter on.
Also, the heat resistant insulation on the igniter leads is somewhat delicate and wont tolerate much manipulation (bending, twisting), so don't monkey with it too much! Its fairly easy to mess up, especially if the technician or owner pulls the burnpot off in the misguided idea that you need to pull it off to change the igniter...you don't, and it makes the job tougher!
As mentioned before, ad nauseum, these igniters are good or bad, not in-between. An igniter that gets hot but "just doesn't seem to produce enough heat to ignite the pellets in the pot" isn't faulty.....its something else....very damp pellets, or more likely, a dirty igniter ("yes, I cleaned the igniter! oh....where is the igniter anyways...?").....it can also be an air issue as well.

 

Well, maybe for a Hormone, but not for other "regular" cartridge-type ignitors. I had one on my 10-cpm that actually went 1/2 bad......it glowed on the 1st half near the mounting flange, but not the outer 1/2. It WOULD eventually ignite the pellets, but took upward of 10 minutes. New ignitor had them going in 2 minutes or less..

 

......are there any other pellet stoves other than Harman?.......

 

Hard to believe for some people, I guess.

 

Hmmmmm...Sounds like a Ford dude trying to talk with a GMC freak

I have seen igniters in the Quads go...some go phfffffft and melt.

Had others get sort of hot but not enough to gitterdone....

I'm old school ya know TORCH IN HAND

I still think this furnace needs a fresh board.

The addition of the timer likely was the result of the failure....what failed and why ???
Was it normal wear and tear ???? .... or was it the result of outside actions ...POWER SURGE OR SOMEBODY FOOLING WITH STUFF.

The board in my Large Whitfield died slowly, with the fan speeds getting wonky over a period of time and then finally the room air fan would not start at all....
My experience with the control boards over nearly 30 years of fooling with pellet stoves has taught me that these parts are very delicate and are actually way too delicate.

The built in safety factor is marginal at best.
Some stoves do not have fuses on the various components to protect the board.

The Whits would eat the board if the room air fan failed.... a simple 2 amp fuse would have prevented that..

The fan speed controls were a weak link in the system and would fry the fan motors.

My action on this furnace would be to check the wiring and the various sub components (Replace any that are sketchy) stuff in a fresh board (Add SURGE PROTECTION) And go again

 

So here is the update. I am actually a millwright in a mill. So I asked my co-worker who is a good electrician to have a look at the board. In two seconds he says the large Triac is gone. Perfect I say, now can you fix it. And the answer "NO". I do not have the tools and I cannot test it. I asked him, "how do you know". The electrician says you can see where it heated and cracked. And sure enough you can see the crack in it. But he gives me a name and sends me on my way. So i take it to the electronics shop he recomends and he says 60$. But he tells me there is actually 2 Triacs that need replacing after testing. Future more, he says he fixes them all the time. So i asked both electricians why? the triacs failed. Both gave the same answer- the Triacs are both on the high voltage side(120 volt) in this case. There are only a few things on the high side- combustion fan, air fan, igniter and auger motor. Furthermore they both said most likely igniter over heated, next the auger, last would be the fans. Both also said to do just a simple load check when I start the furnace again. So thanks for the very good info. I will try again soon, and let you know.

 

so did they resize the triac or add a heat sink? and or add an over current fuseable link( or fuse) to prevent frying triac?

 

Neither. I went home and did an inspection of the igniter and I replaced the igniter to be safe with a new one.
I may install a circuit breaker on the igniter for safety.

 

How would i know if my board should take a red ESP or a black ESP. The electronics man said the board I have is not that old. And I'm looking to make sure I have everything as correct as possible.
Thanks

 

it probably can take either one, you just have to change switch settings if you change colors of ESP

 

What color is the one that's in the unit ????

Get the same color as what's in there.

As LW said....you must change the dips if you swap colors.

The one that was there worked before....just get a fresh one in the unit and life should be good.
Make sure the #5 dip switch is set to OFF FOR ANY COLOR OTHER THAN RED

I scoped out a DIP SWITCH CHART for the PF100

SETTINGS ARE (Finned cartridge ignition)
#5 ON RED wire
1234678 OFF


The two types of igniters
The slim tube type is the pressure igniter and the one with the fins is the finned cartridge

You should be able to identify what you have and where to set things so it will work right.

Make a note of your dip switch settings (Current) and check against whats recommended

Note the piccy of the dip switches All marked 1 to 8
__________________________________________________
1478 OFF (Pressure ignition) 10 RPM
2356 ON

 

K, so my dips are not correct. I have a black wire to my ESP. I have a finned igniter.
So, should all my dips be on "0ff"?