Enviro Mini - Stove Issue After Professional Cleaning

[jfancher]

I have an Enviro Mini that was installed in 2023 (in my mother-in-law's in-law suite apt.), and it get's serviced by the same folks that installed it. I'm having an issue after the stove was professionally cleaned yesterday, where the stove no longer turns on/off properly in the Auto/Off mode using the Thermostat. The stove was running fine before the cleaning, and never had issues after my normal weekly cleanings.

The stove will feed at start up and I'll get a flame. Right around the time the stove starts to blow, there's an audible "click" and the stove starts to wind back down, and will burn the pellets in the burn pot in it's shutdown phase. The Mode light will blink steady, with the #3 light blinking steady in tandem. The hopper is, obviously, not empty and it has a newer ignitor (it failed in 2024...so much for made to last products!) and there is a flame, so it can't be the Fail to Prove Fire problem.

The technician states he did not change any settings, but something is definitely up. I figured maybe it was the combustion trim rate blowing too hard and causing it to flame out, but when I hold the combustion trim button, the mode light never goes solid so I can't seem to change the trim level (or the feeder trim). They offered to come back out to check on it, but I really don't feel like being hit with a service charge for a visit right after paying for two stove cleanings. It runs quite a bit better in High/Low, but the space is too small and it gets way too hot...so that option isn't really a good fix.

I'd like to put the techs feet to the flame but I'm just not sure what's up. Any ideas of what could be wrong would be greatly appreciated.

 

[Whitenuckler]

I have an Enviro Mini that was installed in 2023 (in my mother-in-law's in-law suite apt.), and it get's serviced by the same folks that installed it. I'm having an issue after the stove was professionally cleaned yesterday, where the stove no longer turns on/off properly in the Auto/Off mode using the Thermostat. The stove was running fine before the cleaning, and never had issues after my normal weekly cleanings.

The stove will feed at start up and I'll get a flame. Right around the time the stove starts to blow, there's an audible "click" and the stove starts to wind back down, and will burn the pellets in the burn pot in it's shutdown phase. The Mode light will blink steady, with the #3 light blinking steady in tandem. The hopper is, obviously, not empty and it has a newer ignitor (it failed in 2024...so much for made to last products!) and there is a flame, so it can't be the Fail to Prove Fire problem.

The technician states he did not change any settings, but something is definitely up. I figured maybe it was the combustion trim rate blowing too hard and causing it to flame out, but when I hold the combustion trim button, the mode light never goes solid so I can't seem to change the trim level (or the feeder trim). They offered to come back out to check on it, but I really don't feel like being hit with a service charge for a visit right after paying for two stove cleanings. It runs quite a bit better in High/Low, but the space is too small and it gets way too hot...so that option isn't really a good fix.

I'd like to put the techs feet to the flame but I'm just not sure what's up. Any ideas of what could be wrong would be greatly appreciated.

https://enviro.com/custom_content/docs/manuals/C-14941%20Instruction%20Mini%20A%20Owners%20Manual.pdf

Is this the issue:
2. The stove will not operate when hot. Check the Heat Level Indicator if a fire is not detected, or if the fire has gone out the #3 light will flash because the Exhaust Temperature Sensor’s contacts have opened. Check the hopper for fuel. Incorrect air damper setting. - Excessive air may consume the fire too quickly before the next drop of fuel, leaving completely unburned fuel in the burn pot liner. - Insufficient air will cause build up, further restricting the air flow through the Burn Pot Liner. This in turn will cause the fuel to burn cold and very slowly. Fuel may build up and smother the fire. In this case clean the burn pot. (NOTE: unit may require a change to the vent system or installation of fresh air to correct Air to Fuel ratio problems). Combustion Blower failure. - The Combustion Blower is not turning fast enough to generate the proper vacuum in the fire box. Visual Check – is the blower motor turning. Check the Exhaust Blower voltage across the blower wires (>=114V on #5 setting and >= 82V on #1 setting). – Replace the Circuit Board if the Voltage reading is less than 82 V. with a line voltage >114 V AC. Check Vacuum levels in the exhaust channel by bypassing the Vacuum Switch, then remove the Vacuum hose from Vacuum Switch. Check exhaust vacuum readings by placing the open end of the Vacuum Hose on a Magnahelic Gauge (readings must be above .10” W.C. on low fire). If the motor fails to reach a 0.10” W.C. readings, then replace the Combustion Blower

Johneh here is the expert on these, but what do you have for a thermostat? Are the connections good?

 

[jfancher]

https://enviro.com/custom_content/docs/manuals/C-14941%20Instruction%20Mini%20A%20Owners%20Manual.pdf

Is this the issue:
2. The stove will not operate when hot. Check the Heat Level Indicator if a fire is not detected, or if the fire has gone out the #3 light will flash because the Exhaust Temperature Sensor’s contacts have opened. Check the hopper for fuel. Incorrect air damper setting. - Excessive air may consume the fire too quickly before the next drop of fuel, leaving completely unburned fuel in the burn pot liner. - Insufficient air will cause build up, further restricting the air flow through the Burn Pot Liner. This in turn will cause the fuel to burn cold and very slowly. Fuel may build up and smother the fire. In this case clean the burn pot. (NOTE: unit may require a change to the vent system or installation of fresh air to correct Air to Fuel ratio problems). Combustion Blower failure. - The Combustion Blower is not turning fast enough to generate the proper vacuum in the fire box. Visual Check – is the blower motor turning. Check the Exhaust Blower voltage across the blower wires (>=114V on #5 setting and >= 82V on #1 setting). – Replace the Circuit Board if the Voltage reading is less than 82 V. with a line voltage >114 V AC. Check Vacuum levels in the exhaust channel by bypassing the Vacuum Switch, then remove the Vacuum hose from Vacuum Switch. Check exhaust vacuum readings by placing the open end of the Vacuum Hose on a Magnahelic Gauge (readings must be above .10” W.C. on low fire). If the motor fails to reach a 0.10” W.C. readings, then replace the Combustion Blower

Johneh here is the expert on these, but what do you have for a thermostat? Are the connections good?

Yea, so this is right out of the manual. The Damper on these are set in the factory and we were instructed not to touch it so the damper is still in it's factory position. The ignition process and the shutdown process are normal and don't do anything odd, I'm assuming airflow is good, but like I said...for some reason when I hold the Combustion Trim button down, I cannot adjust the Trim...the mode button blinks instead of going solid and the Up & Down don't change the position of the Trim (same for Feed). I thought this may be the issue because of the possibility of a vacuum issue...but also like I mentioned, I can put it on High/Low instead of Auto/Off setting and it will run pretty much fine.

I do not have the electrical expertise to check voltage and I do not have a Magnahelic Gauge, but the only thing I can think of from a "parts" perspective associated to this would be the exhaust temp sensor. On my Harmon, this sensor is fairly accessible and I have had to wiggle it in the past when we first started using it (it came with our house) but since then it's been fine.

My concern is the Technician did something wrong or adjusted something he shouldn't have. It's a father/son team, nice guys for sure, but the son was solo this time and he has made mistakes in the past that his father has caught while they were together. I don't need him to come out and gaslight my mother-in-law into a ridiculous service visit cost. I wanted to make sure I tapped out all options to troubleshoot myself before relenting to them coming back.

 

[Whitenuckler]

Yea, so this is right out of the manual. The Damper on these are set in the factory and we were instructed not to touch it so the damper is still in it's factory position. The ignition process and the shutdown process are normal and don't do anything odd, I'm assuming airflow is good, but like I said...for some reason when I hold the Combustion Trim button down, I cannot adjust the Trim...the mode button blinks instead of going solid and the Up & Down don't change the position of the Trim (same for Feed). I thought this may be the issue because of the possibility of a vacuum issue...but also like I mentioned, I can put it on High/Low instead of Auto/Off setting and it will run pretty much fine.

I do not have the electrical expertise to check voltage and I do not have a Magnahelic Gauge, but the only thing I can think of from a "parts" perspective associated to this would be the exhaust temp sensor. On my Harmon, this sensor is fairly accessible and I have had to wiggle it in the past when we first started using it (it came with our house) but since then it's been fine.

My concern is the Technician did something wrong or adjusted something he shouldn't have. It's a father/son team, nice guys for sure, but the son was solo this time and he has made mistakes in the past that his father has caught while they were together. I don't need him to come out and gaslight my mother-in-law into a ridiculous service visit cost. I wanted to make sure I tapped out all options to troubleshoot myself before relenting to them coming back.

OK - Johneh is not on line right now to have a look. I had asked about the thermostat? Are you saying the stove will work normally in every mode but Auto/off?

Send Johneh a DM and that will make sure he see's the post

 

[ARC]

Probably to much info in tech manual but try bypassing the exhaust temp switch, page 37

 

[jfancher]

Probably to much info in tech manual but try bypassing the exhaust temp switch, page 37

Definitely going to try this...thank you. It's at least something I can try and easily set back if it doesn't correct the issue.

 

[ARC]

Definitely going to try this...thank you. It's at least something I can try and easily set back if it doesn't correct the issue.

Could be tech loosen wire or snap disk is dirty or lose

 

[jfancher]

Update: Opened the stove up this morning, checked to make sure connections were good. Everything looked okay, however the type of connection on the Exhaust Temp Sensor isn't really the kind I can jump/stack like in the Tech Spec Manual to bypass.

All the fans are working fine, Auger is fine, no blockage. Fresh Air Intake at the Exhaust housing is open. It will run in Manual fine, it's only the two settings associated to the use of the Thermostat, which makes me think the stove is fine and there's something wrong with a sensor either on the stove associated to temperature or the thermostat.

If I force the stove to continue when it starts the error, it seems to work fine through the room reaching temperature and then shutting down based on room temperature. The real issue seems to be when it's cooled a bit between running and it will throw the error right about when the stove gets hot enough and the room fan turns on (again, only after it's cooled between running cycles). The damper is in the factory position and the flame is good when it runs in manual or when I force it past the error. So stumped at this point!

 

[Whitenuckler]

Update: Opened the stove up this morning, checked to make sure connections were good. Everything looked okay, however the type of connection on the Exhaust Temp Sensor isn't really the kind I can jump/stack like in the Tech Spec Manual to bypass.

All the fans are working fine, Auger is fine, no blockage. Fresh Air Intake at the Exhaust housing is open. It will run in Manual fine, it's only the two settings associated to the use of the Thermostat, which makes me think the stove is fine and there's something wrong with a sensor either on the stove associated to temperature or the thermostat.

If I force the stove to continue when it starts the error, it seems to work fine through the room reaching temperature and then shutting down based on room temperature. The real issue seems to be when it's cooled a bit between running and it will throw the error right about when the stove gets hot enough and the room fan turns on (again, only after it's cooled between running cycles). The damper is in the factory position and the flame is good when it runs in manual or when I force it past the error. So stumped at this point!

Johneh is online now

 

[ARC]

Watch this jumper wire vid, you can also just use a paper clip jammed into both spades. Remember unplug stove before you do it and tape the connection do not let bare wires touch body of stove when stove plugged in it will kill your board.

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[johneh]

As said above, check the Exhaust Temp. switch
Start by removing it (2 scews) and clean the face
A coating of ash will stop it from working right.
Start the stove and test to see if it keeps burning
If it does, you are good. If it stops again, jump the
2 wires and retest . If the stove operates as it should,
replace the switch. 9 out of 10 times, it is ash insulation
stopping the switch from obtaining operating temperature.