Englander 25-PDVC Control Board Issues

[gorehound]

Hi all. I'm new here and new to pellet stove ownership. I am working on a stove that I acquired from a friend after we couldn't get it working. The problem is when I plug the stove in, the control board blinks all the LEDs and sometimes pops up an 8 in the heat range window. I replaced the electrolytic caps and the micro and the problem isn't fixed. I have a decent amount of experience in electronics and am hoping to fix this issue without having to spend 200+ on a control board as I am pretty strapped for cash. I was wondering if anyone has experienced this problem and may know which component may be the cause. I took a video of the what the control board is doing. It is the PU-CB04.

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Anyone have experience with this?
Thanks,
Shane

 

[gorehound]

In this video I have hooked the board back up to the stove and plugged it in. I think it is the combustion motor that is running as I can feel it pushing air out where the vent pipe hooks up. I can also feel suction at the air inlet. You can hear the motor stutter as the LEDs blink and pushing the buttons has no impact on the operation. Next video I will show the board hooked up to a 5 volt power supply without any AC hooked up.

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Thanks,
Shane

 

[gorehound]

For this next test I hooked the board to a 5 volt power supply. I connected the positive lead to the output leg of the 7805 regulator and the negative lead to the pin closest to the J11 silkscreen on the VAC BYPASS header. I can power it up this way and the buttons seem to work. I've tried this with AC applied thinking that maybe the regulator on the board is bad, but when I plug the unit into AC it functions the same as the first video. I can't seem to track the problem. I am not an expert in electronics, so I am hoping someone reading this is. I thought it maybe a current draw issue on the regulator, but with AC plugged in and not hooked up to DC power supply, the regulator is putting out 4.95 volts. The transformer is rated for 115AC in and 8-16AC out. I measure a fluctuating 9 to 11 volts DC into the regulator but the voltage out doesn't fluctuate. Does anyone have a schematic for this board (PU-CB04)? Anyway here is the video sorry it is sideways this time.

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Thanks,
Shane

 

[jintoreedwine]

Hey Shane, just out of curiosity, have you tried the normal board reset procedure? If you look around the forums for 25-pdvc control board reset, you can probably find the instructions for how to reset it -- I would try that first. Here is a forum post that describes the procedure: https://www.hearth.com/talk/threads/englander-25-pdvc-burning-like-its-on-9.100311/#post-1283274

Most of this forum just advocate replacing the control board when it goes bad, which may be why no one has responded yet. I personally am not against trying to fix it, so long as you have the ability to do it without damaging it . The board does control all the safety features and such of the stove, so it does warrant special care (it is, literally, playing with fire.)

There is a forum member, stoveguy2esw, he is a stove technician for England Stove Works, the company that makes that stove -- so you might try contacting him and see if he would be nice enough to get you a schematic of the control board. However, as I said, generally speaking most replace the control board when it goes bad so he might suggest the same thing.

In any case, I'm not trying to discourage you necessarily, I'm just trying to be honest about most normally do .

 

[gorehound]

Thank you for the reply I appreciate it. At this point I'm not ruling out fixing the board just yet. Unless there is some internal damage it should be possible. I'm considering it a challenge now. It is difficult to decipher what the surface mount diodes are and a schematic would make it bit easier. I'll update as I learn more.

 

[jintoreedwine]

Thank you for the reply I appreciate it. At this point I'm not ruling out fixing the board just yet. Unless there is some internal damage it should be possible. I'm considering it a challenge now. It is difficult to decipher what the surface mount diodes are and a schematic would make it bit easier. I'll update as I learn more.

I do imagine that would be difficult . I am interested in your findings, as I have often wondered if the boards were salvageable, it probably is the single most expensive part on any stove.

 

[gorehound]

Thanks and to answer your question I am able to do a factory reset as long as I have it hooked to 5 volts. As soon as I plug in the AC the buttons are non responsive.

 

[jintoreedwine]

Thanks and to answer your question I am able to do a factory reset as long as I have it hooked to 5 volts. As soon as I plug in the AC the buttons are non responsive.

Hmmm, that really does make it sound like an electrical component issue vs. a board programming issue. I just read your previous posts again and noticed that you said you tested the DC voltage regular and that the output on it seemed good, that is almost a shame, because that would have seemed like the likely culprit since it sounds like it works correctly with your 5V power supply...

Unfortunately, as I'm sure you realize, the board needs both AC and DC power because the auger/combustion blower/room air blower motors are all powered by AC that comes off the board. I never dug in enough to figure this out, but I always assumed the combustion/room air blowers had their speed controlled by AC voltage regulation which is presumably done by the control board since there are only two power leads going to each motor from the board.

 

[bill3rail]

Just throwing this out there because I cannot help with board diagnostics.
There are board repairer's out there that cost much less than a new OEM board. I believe they send a repaired board out and you send them your non-working board.

Someone here should know who does these repairs.

Bill

 

[stoveguy2esw]

There is a forum member, stoveguy2esw, he is a stove technician for England Stove Works, the company that makes that stove -- so you might try contacting him and see if he would be nice enough to get you a schematic of the control board.

sadly, I do not have access to a schematic for the board , it is made by a company that makes boards for several items and even though they make the board special for us they own the design so they have the schematics. its not even available to me

 

[bill3rail]

http://pelletblowers.com/bbandp/product_info.php/products_id/54

 

[gorehound]

Thanks all for the replies. I'm still not sure I trust the regulator so I am going to hook a scope up to it tonight and see if is just too noisy for the micro to operate correctly. Thanks for finding that link for me too.

 

[jintoreedwine]

sadly, I do not have access to a schematic for the board , it is made by a company that makes boards for several items and even though they make the board special for us they own the design so they have the schematics. its not even available to me

Hey Mike, thanks for the reply! It is a shame you don't have access to the schematics -- but oh well .

 

[gorehound]

Update: I replaced the 7805 regulator and same thing happens. I probed around with the scope tonight and found that the voltage is slightly higher on VPP and VDD when AC is applied. I'm not sure this is the issue because they are still within operating range of the pic. Since the code and schematic are unavailable I can't tell just what impact the pic has on the power circuit. If I remove it and take measurements the voltages the voltages at different points change drastically. I'm in the process of drawing the circuits as I trace them now. I don't see how it can be that hard as most of the functions are code driven, but there is something making this thing not run. There is obviously feedback from sensors to look at too. Does anyone know what all the sensors are?

 

[jintoreedwine]

I can't say I know what all the sensors are, but according to the manual for the stove there would be two vacuum sensors, one gets input from the firebox and one from the combustion blower housing. In addition, there should be a thermal sensor which attaches to the firebox, and there may or may not be a switch which determines whether the hopper lid is open or closed. There could be other sensors that I am not aware of, though.

 

[gorehound]

Thanks. There is a jumper to bypass the vac sensor and I've tried with and without that installed. I have to wait a few days for the nozzles to come in for the hot air station before I can swap more parts. I'm certainly not an electronics expert but find this challenging. I'll keep you posted on my findings if interested. Thanks again.

 

[jintoreedwine]

Thanks. There is a jumper to bypass the vac sensor and I've tried with and without that installed. I have to wait a few days for the nozzles to come in for the hot air station before I can swap more parts. I'm certainly not an electronics expert but find this challenging. I'll keep you posted on my findings if interested. Thanks again.

Indeed, many people do use jumpers when they are testing to see whether or not a given sensor has failed, though it is not recommended that you run the stove that way for a prolonged period of time, obviously.

Note that, when the stove control board is operating normally, those sensors are simply used by the control board to determine whether the top auger motor should be allowed to run or not. The bottom auger of the stove will spin continuously until the stove determines it is safe to shutdown completely and the top auger will spin intermittently assuming that the input from all the sensors is acceptable.

I can't say I have ever heard of those sensors causing the control board to do funny things, though. Normally, a failed sensor just means that the stove will not run properly -- but the stove will still try to run initially in most cases. Still, it will be interesting to hear what you find as you continue to diagnose the problem .

 

[gorehound]

I think I got it. I swapped D9 and D7 on the board, plugged it in and it came up 2 4 as it did with just DC power. I pressed the on button and it went to S U. I'm assuming 20 minutes later or so it will bomb out with an error of some sort because I don't have it hooked up to the stove yet. I pressed the off button and it went to S d mode and shortly after turned off. Once I find a replacement diode for the ones I swapped I will put it back together and update whether it's truly working. I'm not sure what circuit D9 has to do with but D7 looks to be part of the temp sensor circuit.

 

[jintoreedwine]

I think I got it. I swapped D9 and D7 on the board, plugged it in and it came up 2 4 as it did with just DC power. I pressed the on button and it went to S U. I'm assuming 20 minutes later or so it will bomb out with an error of some sort because I don't have it hooked up to the stove yet. I pressed the off button and it went to S d mode and shortly after turned off. Once I find a replacement diode for the ones I swapped I will put it back together and update whether it's truly working. I'm not sure what circuit D9 has to do with but D7 looks to be part of the temp sensor circuit.

Awesome! What you describe does sound promising .

 

[gorehound]

Update again. The stove works! The autostart feature works and everything else so much as I can tell. I need to learn how to use it now, which is probably a post for another thread.

 

[jintoreedwine]

Great! Glad to hear all that effort diagnosing it paid off .

 

[gorehound]

Thank you again jintoreedwine. You motivated me to keep going on this. I almost caved and purchased a new board.

 

[harley75]

I know this is a old posting is there anyone that repairs the Englander 25-pdvc control boards.

 

[gorehound]

I know this is a old posting is there anyone that repairs the Englander 25-pdvc control boards.

I don't know of anyone who does. I have a little bit of electronics knowledge and was able to find the problem with mine. I'm not sure if your problem is the same or not. You can have a look at the videos I posted and if your problem is the same it might be the diode I replaced in mine. Good luck and I can try to help.

Sent from my SM-G935F using Tapatalk

 

[harley75]

Well my trouble is with the unit plugged into the wall the bottom auger keeps turning and the unit not even turned on yet