Blown Fuse in my St Croix Hastings pellet stove

[Jim Kassal]

My basement went cold and upon investigation, I found my pellet stove to be off. Its a Hastings by St Croix. It acted like it was unplugged but it was not. Upon checking the fuse, it was blown. I replaced it but still nothing. It did not blow again, but it still acts like there's no power. I checked for 120 volts on both sided of the new fuse and it is there. But there's no response to pressing the ON button to start it up. I replaced the control board several years ago. Should I assume it is bad again?

Any suggestions?

 

[Whitenuckler]

My basement went cold and upon investigation, I found my pellet stove to be off. Its a Hastings by St Croix. It acted like it was unplugged but it was not. Upon checking the fuse, it was blown. I replaced it but still nothing. It did not blow again, but it still acts like there's no power. I checked for 120 volts on both sided of the new fuse and it is there. But there's no response to pressing the ON button to start it up. I replaced the control board several years ago. Should I assume it is bad again?

Any suggestions?

https://stcroixstoves.com/wp-content/uploads/2020/03/Hastings-Manuals1.pdf

I don't see a wiring diagram, but check the high limit switch and try to reset it

 

[Jim Kassal]

I see reference to a high limit switch in the manual but don't know where to look for it. And, if that high limit switch tripped, there would be indicator lights blinking. This stove is electrically dead.

 

[Whitenuckler]

I see reference to a high limit switch in the manual but don't know where to look for it. And, if that high limit switch tripped, there would be indicator lights blinking. This stove is electrically dead.

I see reference to a high limit switch in the manual but don't know where to look for it. And, if that high limit switch tripped, there would be indicator lights blinking. This stove is electrically dead.

Part 5 - I don't have a wiring diagram, but I have seen these switches wired into the controls.
Edit - If you measured 120V to the neutral on the board (not ground) before and after the fuse, and it's not the high limit, then perhaps the power supply part of the board is bad ie the DC might not be there.

 

[Ssyko]

It may be up near the feed Shute or near the top of the fire chamber. Will have a reset in between terminals,”. Will be on the outside of stove and looks similar to this follow wires

 

[Jim Kassal]

Well, I can think of no reason that the high limit switch would cause a fuse to blow so I am going to assume the board is dead and get a new one. I may try to rebuild the DC supply circuit on the old one if I can find a schematic diagram for it.

 

[Whitenuckler]

Well, I can think of no reason that the high limit switch would cause a fuse to blow so I am going to assume the board is dead and get a new one. I may try to rebuild the DC supply circuit on the old one if I can find a schematic diagram for it.

I was thinking that the high limit switch might be wired in series with the AC circuit....not that it would blow the fuse. Blowing the fuse could have been the control card failing.

 

[Jim Kassal]

Does anyone have any ideas about where I might find the circuit diagram for the control board? I can probably trace the circuit to the DC Supply components but the diagram would be helpful.

 

[Ssyko]

If the Dc side blew the fuse you may as well get a control board. But it’s very rare to let the smoke out of that side. The high limit switch controls all 120vac supply to the stove. The wire diagram show 0 locations, this is out of the Hastings manual at least it has the wire colors so you can follow them

https://stcroixstoves.com/wp-content/uploads/2020/03/Hastings1.pdf

 

[Jim Kassal]

Thank you all for the help and suggestions. I'm waiting for the new board, then I'm going to trace the circuit of the old one to the DC supply section and see if there is a chip that failed that can be replaced. I'll report back on how this turns out.

 

[Jim Kassal]

I just received and installed the new control board. Still nothing. I verified once again that there is 120v at the fuse so it is connected to the AC power. I also found the high limit switch and with the unit unplugged, I checked for continuity through the switch and there is continuity. Then I plugged the unit in with the wires off the switch terminals and found there is no line voltage across the two connectors. The wiring diagram suggests there should be. I'm beginning to suspect a broken wire somewhere so I am going exploring for that. Not an easy task with my stove tucked into a fireplace. But it still doesn't make any sense to me that I have no LED lights coming on. No response at all, just like the unit is not plugged in. Any other suggestions would be greatly appreciated.

 

[Whitenuckler]

I just received and installed the new control board. Still nothing. I verified once again that there is 120v at the fuse so it is connected to the AC power. I also found the high limit switch and with the unit unplugged, I checked for continuity through the switch and there is continuity. Then I plugged the unit in with the wires off the switch terminals and found there is no line voltage across the two connectors. The wiring diagram suggests there should be. I'm beginning to suspect a broken wire somewhere so I am going exploring for that. Not an easy task with my stove tucked into a fireplace. But it still doesn't make any sense to me that I have no LED lights coming on. No response at all, just like the unit is not plugged in. Any other suggestions would be greatly appreciated.

Are you doing all your voltage checks with the neutral that is wired to the stove? I'm not sure if I understand the switch issue. You can check the switch with no power, no connections and an ohmeter.

 

[Jim Kassal]

Yes, I just double checked that my line voltage measurement at the fuse was to neutral (white wire) at the terminal
block where the power wire comes in through the back. And the continuity check through the high limit switch was without power and connectors removed.

 

[Jim Kassal]

And I also found that there was no voltage at the wires coming to the high limit switch.

 

[Jim Kassal]

Mystery solved... sort of.... I decided to check continuity from the Molex connector to the terminal block where all the neutral (white) wires are attached. And there was no continuity. Upon investigating I noticed an empty spade and then I saw the wire (with spade connector) that had been attached there. Upon plugging it in, I confirmed continuity. Then with the Molex connector still off the board, I plugged the stove in and checked for 120 v across connector pins 11 and 12 and the expected voltage was there. Upon reassembly, and pushing the ON button the unit sprang to life.

There are still the mysteries of how that spade connector could have come off by itself and why the fuse blew. And it was definitely blown. I can't come up with a scenario wherein the unexpected disconnection of the common ac voltage lead would cause the fuse to blow. Unless it is an induction thing with a motor running and the connector didn't pop off cleanly but rather went intermittent at first. It's possible that could have caused some surge currents. Right now, I do not know if the original board is functional but I suspect it is.

All that said, I may now have an issue with the burn level control because the auger does not seem to be feeding pellets fast enough. Even though it is set to level 5, the feed rate seems more like level 1 or 2. I need to do some investigating before I can be certain that something not right. But after 20 minutes of running on level 5, the stove is not real hot, more like a level 2 burn. The auger cycles on for a very brief interval each time it does. The manual feed works to feed in more pellets. But I am wondering if there is a set screw that loosened so that the motor is not turning the auger properly. Otherwise, the control board is not doing what it is supposed to.

 

[Whitenuckler]

Mystery solved... sort of.... I decided to check continuity from the Molex connector to the terminal block where all the neutral (white) wires are attached. And there was no continuity. Upon investigating I noticed an empty spade and then I saw the wire (with spade connector) that had been attached there. Upon plugging it in, I confirmed continuity. Then with the Molex connector still off the board, I plugged the stove in and checked for 120 v across connector pins 11 and 12 and the expected voltage was there. Upon reassembly, and pushing the ON button the unit sprang to life.

There are still the mysteries of how that spade connector could have come off by itself and why the fuse blew. And it was definitely blown. I can't come up with a scenario wherein the unexpected disconnection of the common ac voltage lead would cause the fuse to blow. Unless it is an induction thing with a motor running and the connector didn't pop off cleanly but rather went intermittent at first. It's possible that could have caused some surge currents. Right now, I do not know if the original board is functional but I suspect it is.

All that said, I may now have an issue with the burn level control because the auger does not seem to be feeding pellets fast enough. Even though it is set to level 5, the feed rate seems more like level 1 or 2. I need to do some investigating before I can be certain that something not right. But after 20 minutes of running on level 5, the stove is not real hot, more like a level 2 burn. The auger cycles on for a very brief interval each time it does. The manual feed works to feed in more pellets. But I am wondering if there is a set screw that loosened so that the motor is not turning the auger properly. Otherwise, the control board is not doing what it is supposed to.

Excellent - one problem solved. Are you going to put your "old" card back in? That might check your operation issues and also you can check for more fuse blowing. I'd say you are right, if the neutral is bad, and causing surging, the fuse will blow due to all the inrushes.

 

[Jim Kassal]

Well, the last issue is solved. I forgot that the board needs to be set to program 3 for the Hastings and it slipped my mind for a bit. Now that it's reset, all's well. But not until I verified the set screw was OK and vacuumed out the auger housing to clear it of dust. It needed cleaning anyway,. Because the board is not returnable, I plan to leave it installed. But I will keep the old one as a back-up should there be another problem.

 

[Ssyko]

The fuse probably blew from the spade connector floating around/vibrations. Glad you figured it all out. Enjoy the Heat 😎