Pellet Stove has Died....Need Assitance

[ripogenus smelt]

Hi,

I have a 10 year old pellet stove made by Reliant Industries. The model name is Essex and Serial number is 2220. HTis week it stopped working. No auger feed and no igniter function. So I started to investigate and found the problem. It is a burnt resitor on the board that comes into the stove.

I would like to repair this board (I have the solder iron, solder, and resistors at Radio Shack, etc.) but what I can not tell is what the original color code banding on the resistor. Can anyone help me out with determining this....or make a good guess?

The fuses on this board are 6 amp. I can not get any more clues about the board looking at the owners manual.

Maybe someone out there has had this problem or has an ide fo rme to try.

Also...if anyone can help me find where Reliant Industries went and if the new company still supports these models that would be helpful. The pellet stove works great and hasnt missed a beat in 10 years...until now.

Here are a few pictures below of the stove and board.

 

[timbo]

Is the resistor open? can you get any reading with a meter on it? It may still be good but overheated which has made the outer coating slough off. If you do figure out what the value is, I wouldn't replace it until you've determined what caused the resistor to cook (maybe one of those diodes or filter caps has shorted). It may be that the resistor wattage was specified too low as well. A larger 5 watt resistor may be in order.

 

[1BadTitan]

Did you try to google for a manual for it? You may find a schematic in there.

 

[timbo]

Here's a webpage that sells (or sold) these stoves. If you click on support, there's a phone number that will allegedly get you in touch with someone that may be able to help you out.

(broken link removed to http://www.cornburns.com/essex.htm)

Google is my friend... :coolsmile:

 

[smalltown]

I tried looking around the web for you did not see any schematics, nor any info on E-bay. I did however find an owners manual for Essex Magnum T40AC, T40DC, T40I, ESSEX,
Wood Pellet Stove / Fireplace Insert dated 2004

(broken link removed to http://www.americanenergysystems.com/downloads/public/Reliant_T40_Essex_Manual_2004.pdf)

Maybe the company is still in business, but not producing pellet stoves. I'd try a call. There are some tel numbers listed in the manual or else google the company and ask if there is a possibility of a schematic on file somewhere.

 

[jtakeman]

Company is still in business.

This link has all the documents For the essex stove.

(broken link removed to http://www.americanenergysystems.com/owners-manuals.cfm)

There is also a place to order parts.

(broken link removed to http://www.americanenergysystems.com/replacement-parts.cfm)

Looks like the part you need is the power supply. It converts 120 volts ac to 12 volts dc.

I really doubt the resister is the only failure on the power supply. It is the only visible one. I would just order a new power supply. Then you can tinker with the old one as a spare.

 

[smalltown]

Nice find jtakeman!

I agree the resister went bad most likely because another part shorted out.

 

[jtakeman]

Nice find jtakeman!

I agree the resister went bad most likely because another part shorted out.

I found it from your link. So you should have the credit.

I just used the http://www.americanenergysystems.com from your link.

And browsed from there.

 

[webbie]

Yes, I think American Energy bought some designs from Reliant....so although Reliant is not in biz, much of the technology and paperwork should be available.

 

[jtakeman]

RP2011 power supply

I think that is the part you are looking for.

 

[ripogenus smelt]

Thanks everone...I really appreciate your help. Any ideas on what may have shorted something out?? I'll look into getting a new board...and trying to repair this one for fun!

 

[jtakeman]

Thanks everone...I really appreciate your help. Any ideas on what may have shorted something out?? I'll look into getting a new board...and trying to repair this one for fun!

I would suspect a diode to have failed. But the only way I know is to remove each componenet and start testing.

Personally I would replace anything that even slightly looks bad or discolored.

Hopefully the power supply failure hasn't hurt the control panel.

 

[timbo]

That appears to be a current limiting resistor in the external battery charger circuit that burned out because the battery was either shorted or otherwise defective. If you replace or repair the board, I would recommend replacing the back up battery too (or make a note of what the resistor value is).

 

[UncleAnthony]

As Jtakeman stated, check the diode, it is most likely bad. Tried to find schematic at the links provided(thanks) no luck. Your picture is excellent though, so I will throw my 2cents in.
Do you have a voltmeter?
Did either of the onboard fuses blow ?
Looks like some discoloration at top-left of board, above top capacitor, looks like resistor ?
Can you check the ohms of this resistor?
In a regulated supply as this, transformer to rc network to regulator produces dc volts.

disconnect the transformer leads.
lift one leg of diode, check diode.
try to check burnt resistor value, may get something.
check that transistor at bottom of board below fuse. Does this transistor follow trace to resistor thru that bottom cap ? I may suspect the cap then, but most likely this transistor and that diode is culprit and will fix problem with about $6 in parts. But lets go on.
Can you check the transformer windings while disconnected ? Should be same value when checking adjacent leads (i think). Anything extremely low to a short would indicate shorted windings.
If you check on the board, there should be a mfg and board number. try googling that to find what
resistor you need that is burnt.
As long as the transformer is good, the other parts on this board are inexpensive and common.
Please keep us updated.

 

[timbo]

check that transistor at bottom of board below fuse. Does this transistor follow trace to resistor thru that bottom cap ?

That's not a transistor...it's a full wave bridge rectfier (the black rectangular part between the fuses). The part below the bottom fuse and the up against the filter cap is a low voltage, hi current diode common to relatively hi amp/hour battery charging circuits.

That lower large diode is being used as a switch so when voltage drops below terminal voltage of battery (as in when you lose power), it automatically kicks the battery into the DC power buss to run the fans in the stove.

 

[jtakeman]

...it's a full wave bridge rectfier (the black rectangular part between the fuses).......

I agree. Also if you look at the other photo. It looks to have some discoloration. Very bad if one of the diodes in the bridge have failed. DC components do not like seeing AC.

 

[UncleAnthony]

check that transistor at bottom of board below fuse. Does this transistor follow trace to resistor thru that bottom cap ?

That's not a transistor...it's a full wave bridge rectfier (the black rectangular part between the fuses). The part below the bottom fuse and the up against the filter cap is a low voltage, hi current diode common to relatively hi amp/hour battery charging circuits.

That lower large diode is being used as a switch so when voltage drops below terminal voltage of battery (as in when you lose power), it automatically kicks the battery into the DC power buss to run the fans in the stove.

Timbo,
thanks for clearing that up. Looking at the picture closer , i do see that the "transistor" is actually a diode.
I thought that may be a bridge rectifier in the middle of the board. Did not know about the battery backup option.
thanks again.

 

[timbo]

...it's a full wave bridge rectfier (the black rectangular part between the fuses).......

I agree. Also if you look at the other photo. It looks to have some discoloration. Very bad if one of the diodes in the bridge have failed. DC components do not like seeing AC.

If one leg of the bridge rectifier shorted to another, then the mains fuse would blow...if it hasn't blown then the bridge rectifier is fine. I'm curious what DC components don't like seeing AC?

I think the discoloration you're seeing is dust and/or ashes. The only discoloration I see on the PCB that would be indicative of something getting too hot is under that power resistor. Everything else appears normal.

 

[jtakeman]

...it's a full wave bridge rectfier (the black rectangular part between the fuses).......

I agree. Also if you look at the other photo. It looks to have some discoloration. Very bad if one of the diodes in the bridge have failed. DC components do not like seeing AC.

I'm curious what DC components don't like seeing AC?

Wire a DC 12V motor to AC and tell what you would get? Precaution to what maybe damaged beyond the power supply. If the fuse is OK. Agreed, things should be fine. Hard to judge anything when its not on the test bench.

Guess I'm a worry wort. Blown components lead to other blown components. Been there a few times where a simple looking fix ends in a nightmare.

 

[timbo]

...it's a full wave bridge rectfier (the black rectangular part between the fuses).......

I agree. Also if you look at the other photo. It looks to have some discoloration. Very bad if one of the diodes in the bridge have failed. DC components do not like seeing AC.

I'm curious what DC components don't like seeing AC?

Wire a DC 12V motor to AC and tell what you would get?

Assuming you're connecting a 12 VDC motor to 12 VAC, it depends on whether the field winding of the dc motor is connected in series or in shunt with the armature winding. If it is connected in series,the motor will rotate since the torque,which varies as the product of the armature and field current is always positive.Thus,a positive average torque causes the motor to rotate, however the pulsating nature may cause the commutator segments and brushes to wear out. If it is wired in a shunt configuration, it'l just vibrate pretty loudly at 60 cycles as it tries to turn one way, then the other as the current varies above and below 0 volts. Eventually, it would probably burn out the brushes.

 

[CanadaClinker]

......my shot at the circuit board above is this..... assume the AC supply is making 14V DC (after the rectification) and supplying to the UPPER diode before it gets to this burnt resistor. I believe it looks as if this diode is part of a trickle charging circuit for the battery. If this is the case, there would be 14V (approx.) on the positive side of the upper diode, 13.3V on the bottom side )(0.7V drop) next to the burnt resistor.

The bottom trace from the bottom of the burnt resistor goes down to the BIG diode which I think timbo is correct is saying it switches the backup battery to the DC buss. The one lead of the positive side of the big diode is in contact with the red wire (which goes to the battery). That's how the 'trickle' gets to the battery.

Now back to the burnt resistor in the 'trickle' circuit. If the upper part of the resistor has 13.3V (as said above), and the battery was sitting at 11V, then 2.3V would be across the burnt resistor.

Now this is where it gets tricky..... the diode above appears to me as a 1A diode in size. (possibly a 1n4001). Using ohms law, R=E/I then the smallest resistor at the max amps of the diode would be ... R=2.3V/1A =2.3 ohms. To make it a 500mA trickle to protect the 1A diode, then the resistor would have to be 4.6 ohms. I would probably be safe and put in a 10 ohm resistor and at ohms law .... I=E/R or I = 2.3V/10 =230mA of trickle current for the battery.

The wattage should be P=E squared/R or 2.3 x 2.3 /10 = 0.5W if you can find a 1W, that would be better.

I think timbo also said above (and I agree with him) that a 'bad' battery with voltage below 11V (say 5V) would put undue strain on the trickle resistor and cook it like crispy chicken.... :lol:

I would also check the 'trickle' diode to make sure it isn't shorted because of the current .... but it probably is ok as resistors being cooked usually get more resistant and reduce the current as they are 'cooking' (carbon do this.... wire wound, which this appears in the pic to be, usually open)....

....a good picture of the back of the cct board would help draw out the circuit along with the number off the UPPER diode would help .... my 2 cents.....cc :cheese:

 

[timbo]

C/C,
I was going to ask the same thing of Mr Smelt...see if we can reverse engineer this thing...it looks like a simple half wave rectified battery charger but it also appears to incorporate the FW rectified voltage for the DC motors. "typically" a charger charges a battery at 15-20% over rated battery terminal voltage and about 10-20% of the rated AH rating of the battery. I'm going to take a SWAG at the resistor and gues it's probably in the 5-10 ohm range...being strictly used as a current limiting resistor so if charger is hooked up to a dead (or low) battery, the charging current (which will be pretty high at this point in time) won't fry the transformer used in the charger trying to pull tons of current from it...as the battery charges up, it will look less and less like a short and the voltage drop (therefore the current through the resistor) will diminish.

 

[CanadaClinker]

C/C,
I was going to ask the same thing of Mr Smelt...see if we can reverse engineer this thing...it looks like a simple half wave rectified battery charger but it also appears to incorporate the FW rectified voltage for the DC motors. "typically" a charger charges a battery at 15-20% over rated battery terminal voltage and about 10-20% of the rated AH rating of the battery. I'm going to take a SWAG at the resistor and gues it's probably in the 5-10 ohm range...being strictly used as a current limiting resistor so if charger is hooked up to a dead (or low) battery, the charging current (which will be pretty high at this point in time) won't fry the transformer used in the charger trying to pull tons of current from it...as the battery charges up, it will look less and less like a short and the voltage drop (therefore the current through the resistor) will diminish.

.....right on timbo.....reverse engineering from the back of the board is something I have done on occasion and gone cross eyed and cross brained to jot down the circuit to make sense of it. If we can save Mr Smelt $100 for want of a penny part, it's worth doing. It will also show us if there is any 'trace' damage on the back of the board.

One question I have however, is, in spite that the charging circuit is toast, how does that make his stove dead. I dont think that the rest of the equipment was running through this simple charging cct. (since the upper diode n the pic is only a 1A max.).... it may have been feeding it's voltage down through the big diode and into the control cct and bringing it to life.... I would guess that first changing the resistor out with a value between 5 & 10 ohms will let us know.

Don't know what is available at Radio Shack but the 10 ohm (brown, black, black) may be easier to come by and in that 1 Watt value/size. ..... wonder what Mr Smelt thinks of this idea.....cc :cheese: