Question regarding combustion blower longevity

[709GADE]

Just wondering if you run your combustion blower at a higher rpm constantly, will it shorten it's lifespan vs. Running at a lower rpm?

Thanks

 

[rich2500]

Pretty much the harder you run anything the harder it will be on the item.

 

[Bioburner]

I think the heat and dust environment has a lot to do with how long some of the motor fan assemblies last.

 

[Mark_ms]

Although I am not the original owner my combustion motor lasted 22 years before I replace it last year.

 

[Peterfield]

Installed my stove Nov 2014 and the combustion motor had to be replaced two months ago. Tech told,me it's a crap shoot and because the motors are magnetic, oil is of marginal if any value and putting a new motor in is the only real solution when motors start vibrating and making noise.

 

[Harman Lover 007]

In general, most combustion blowers run at a constant rpm (to satisfy the vacuum switch) and aren't adjustable via a dial or knob on the control panel. Did you mean distribution blower/fan?

 

[709GADE]

On the Piazzetta Monia I have the combustion blower RPM is adjustable via the electronic display

 

[rona]

In general, most combustion blowers run at a constant rpm (to satisfy the vacuum switch) and aren't adjustable via a dial or knob on the control panel. Did you mean distribution blower/fan?

I know several stoves if not all that are variable speed exh fans. Think about this for a minute if your stove is set on low very little fuel is dumped into the pot so it takes less air to burn the fuel but if you turn the stove on high more fuel is dumped and you need more air to burn the added fuel efficiently. This is done by speeding the exh fan up. Sometimes this is done automatically by the electronic control board and with others there is a knob that can used to adjust the exh fan speed to fine tune the burn in order to burn different fuels.

 

[709GADE]

On the Piazzetta, both combustion air/fan and fuel amount can be adjusted separately. For low quality pellets a lower fuel rate and higher combustion air will lead to a better burn. This is actually the reason for my initial question, I have some low quality pellets that I want to get rid of, so I need to really increase the combustion air.

 

[Harman Lover 007]

I don't believe that is the case with my Harmans. The combustion blower runs at a constant speed at 119V. The only time that would be adjusted is if one was setting the default draft adjustment upon installation of the stove.

 

[Golfeur]

I adjust the draft on my own to the setpoint in the manual and I can say that the speed of the combustion motor changes depending on demand. This is done automatically

 

[MadMax31]

Painting a broad stroke here, but running a motor under its rated under for considerable amounts of time is bad for the bearings. If it is designed for prolonged RPMs below rated speed, then all is well. In the HVAC world we slow condenser fans in winter time to maintain proper operations. This beats up those motors even with their larger ball bearings. The only way to truly slow or spin-up a motor is with a VFD/AFD. At that point the motor as a whole is purpose built.

If your stove came with a variable speed combustion motor, use it how you see fit. It should have been designed to operate at low RPMs. If its rated for 3600 RPMs you can run it there all day every day as its rotor is wound for 3600 RPM.

 

[rona]

I don't believe that is the case with my Harmans. The combustion blower runs at a constant speed at 119V. The only time that would be adjusted is if one was setting the default draft adjustment upon installation of the stove.[/QUO

If you run the stove at a high temp the exh fan will be running as fast as it can to burn the pellets that are dropped into the pot to achieve the high temp. If you set the stove at a low temp it will auger less pellets and the exh fan motor will run at a lower speed to burn less pellets. As proof turn the stove on high and go outside and put your hand in front of the exh pipe and feel the air being pushed out. Now go back inside and turn the stove down to a low temp. Wait about 45 minutes then go back outside and hold your hand in front of the exh pipe. You should just barely feel a slight air movement.

 

[Harman Lover 007]

Like I said, that is not my experience with either of my Harmans. The combustion blowers run at a constant speed.

 

[bags]

I think more wear and tear is at start ups and shut downs on many electrical motors. Running constant is less wear and tear if they are within their specs. Some motors last a long time while others are short lived and this has so many variables you can not do fair comparisons nor ever predict how long they will last.

Dusty conditions, how well Rodriguez slammed it together on the assembly line, on and on. Simple maintenance makes anything last longer. Cleaning and lubes will give longevity. That said though many are sealed units that really can not be lubed. Just like some U-joints and drive train components on vehicles.

Stupid? Yes it makes about as much sense as welding the hoods shut so you can not maintain them.

 

[Pascal_Maertens]

Installed my stove Nov 2014 and the combustion motor had to be replaced two months ago. Tech told,me it's a crap shoot and because the motors are magnetic, oil is of marginal if any value and putting a new motor in is the only real solution when motors start vibrating and making noise.

sometime the vibration is only cause by a displacement of the stove, if you lift one end of the stove and let it bang on the floor instead of put it gently down well this will almost automatically end in a vibration and the impellers can also make noise cause there is a fine gap between the impeller and the casting. it will make a very clear bling bling bling noise, some time you just hit the blower when not running and it will stop.

 

[Pascal_Maertens]

In general, most combustion blowers run at a constant rpm (to satisfy the vacuum switch) and aren't adjustable via a dial or knob on the control panel. Did you mean distribution blower/fan?

when we talk about Piazzetta the combustion and the convection fan are totally adjustable from 1000 to 3500 rpm if unlocked. and for now I havent found any North American stove that can do this yet. I have a great taught that Hearthstone pellet stove can do the same. But for now I've written to the company tech, two weeks a go, and still havent had a response from them. They seem to have the same combustion fan motor but is it adjustable ??? maybe with in a month or two I'll get an answer never know. hopping to find a similar product of the Piazzetta in North America and no one as ever came with one.

 

[Bioburner]

I havent found any North American stove that can do this yet

None that is still in business

 

[Pascal_Maertens]

None that is still in business

and which one was that ?

 

[Bioburner]

Bixby. With the computer program and cable nearly thirty things to mess up

 

[rona]

Bixby. With the computer program and cable nearly thirty things to mess up

But still one of the most efficient stoves made once you understand them

 

[Bioburner]

Unfortunately "was made"
Have enjoyed it for 8 heating seasons, well one year not so much when corn went over $7 and the pellets I had were ash kings.

 

[Pelleting In NJ]

Unless the winding fails, it is the bearing that determines the life of the motor. There are just so many revolutions of life in a bearing. But, it really will make no difference...assume you need X BTUs of heat in each winter. If you run your combustion blower at a lower speed, the stove will have to run a longer amount of time to get the total needed BTUs to keep you warm. If you run the blower at max speed, then the stove outputs more BTU per hour, and you will run the stove for less total time......so the total revolutions that the bearings are subjected to are the same....and the motor life will be the same.

However, running a motor at lower speed might result in a lower motor temperature.....which might extend the life of the winding or bearing.....but I bet this is not a significant factor as to how long the motor will last.

 

[rona]

Unless the winding fails, it is the bearing that determines the life of the motor. There are just so many revolutions of life in a bearing. But, it really will make no difference...assume you need X BTUs of heat in each winter. If you run your combustion blower at a lower speed, the stove will have to run a longer amount of time to get the total needed BTUs to keep you warm. If you run the blower at max speed, then the stove outputs more BTU per hour, and you will run the stove for less total time......so the total revolutions that the bearings are subjected to are the same....and the motor life will be the same.

However, running a motor at lower speed might result in a lower motor temperature.....which might extend the life of the winding or bearing.....but I bet this is not a significant factor as to how long the motor will last.

The bearing quality will make a huge difference on how long the motor lasts. A motor could use several types of bearings but where it is located will determine the type of bearing used. The lubricant in the bearing will also play a big role.

 

[TStark]

Indeed.
Got 17 years on my first comb blower. H Invincible T, toggles between two speeds, electronically 120 or 75 RMS , firing or coasting.
three speeds if you cound shutdown, don't know that voltage.. Just a little oil on the bushing couple times a year.

Now use the B/B upgrade 1.75A motor made for the RS.