Pellet stove problems are infrequent, but pellet stoves being mechanical devices, can develop faults. The main cause of difficulties when using a pellet stove is lack of regular and thorough cleaning. Cleaning procedures are essential to avoid a build up of ash which can undermine the efficiency of your stove. (See links at the bottom of the page).
Many modern stoves have digital circuit boards on which LED's glow in certain combinations to diagnose pellet stove problems. For an explanation of what these lights mean, you will need the manual for your stove.
When servicing a pellet stove, make sure that the unit is unplugged from the electricity supply if there is any chance of coming into contact with electrical parts. If the unit needs an electrical supply to be re-connected to test a component, be very very careful.
Before venturing inside your stove's workings, a good idea is to give it a clean up. This will make the job a lot less messy and reduce the likelihood of small parts being mislaid. When working on the stove, spread a drop cloth around the working area to prevent fly ash getting into floor coverings.
First, check the fundamentals. Is there power to the stove, and are there pellets. Check power to the stove by plugging another appliance, such as a portable, lamp into the socket that the stove takes power from. Check the level of pellets in the hopper.
Occasionally, a pellet stove problem can be pellets bridging over the hopper outlet and prevent themselves from dropping to the auger. If you suspect that this might be what's happened, disconnect the power supply and empty the hopper gently until you get to the bottom. This problem can be caused by over long pellets, or friction with the hopper sides. If pellets won't slide, a light spray over the inside of the hopper with silicon lubricant will help.
With the hopper empty, it's usually possible to see the auger. Switch the power back on, start the stove, and see whether or not the auger is turning. If a slight movement only can be seen, the probability is that it's jammed either by fines, (pellet dust), or a foreign body. Listen for the auger motor to check whether or not it"s working.
Some stoves have a switch on the hopper lid to stop the stove if the hopper is open. This will need to be depressed to view the auger operation. Auger gear motors are very powerful and on no account should fingers come anywhere near a moving auger.
The igniter may be faulty. In normal operation, they can usually be seen to glow red on start up. If you have a faulty igniter, it's possible to start most stoves by using a handful of pellets in the burn pot and lighting them with starter gel. Thermostat on/off operation will not be possible until a new igniter is fitted.
The next step is to get out the manual or download one online, (they are available on the home website of nearly all manufacturers), and find where the stove's internal fuses are,take them out and check them using a continuity checker.
You've checked the hopper and the auger as above? If the stove has run out of fuel, it will take a few minutes for the empty auger to fill and start delivering fuel to the burn pot.
If the auger is jammed with fines, (dust from the pellets), it might be possible to free it by working from both ends with a screwdriver, wire rope, and a vacuum cleaner. Stove power off for this operation. If a foreign body such as a woodscrew has got in there, the auger will need to be dismantled to clear it. Instructions in the manual
Some stoves have 'snap switches' which turn off the auger if the stove should become overheated. Check to see if these need re-setting or are faulty.
For one reason or another, not enough air is getting to the fire. The most common cause of this type of pellet stove problem is a clinkered up burn pot which can be because of inadequate maintenance or poor pellet quality.
Take the burn pot out and give it a thorough cleaning. Scrape off the clinkers using the tool provided with the stove, or an old screwdriver. Make sure that all the air holes are clear. A portable drill can help with this, but get a drill bit the right size or slightly smaller. You do not want to enlarge the holes.
Next, have a look at both the inlet and the outlet venting, including exhaust vents within the stove itself.
The air intake, if from outside, should have a mesh cover to stop leaves and other debris, as well as small animals from entering. Check that the intake is clear.
Stoves have exhaust channels within the stove body which can fill with fly ash. Check your manual for instructions on cleaning these. The flue system can also have a build up of fly ash, particularly at elbows. Sometimes the rain cap can become clogged.
Pellet stove combustion is powered by air blown from the combustion blower. If there is an air leak from the stove door or the ash pan seal, this can cause a shortage of air to the flame.
If the air intake is adjustable, check to see that it's in the correct position and has not been accidentally moved.
That leaves the combustion blower itself, which may just need the fan cleaning, or it may be faulty.
If there has been a power failure, this may have caused the stove to shut down.
The vacuum switch which detects whether or not the flue is blocked may have failed, or more likely, the plastic hose that it is connected to has cracked.
The device that detects the presence of a flame may not be working. This can take the form of a 'photo eye' or a low limit snap disc which tells the stove to run automatically after start up temperature has been reached.
It can happen that too much air is being allowed to enter the burn pot, consuming the pellets there and extinguishing the fire before the stove can feed more pellets. Look for partially burned pellets 'popcorning' out of the burn pot.
When the stove arrives at operating temperature after start up, the convection blower should come on automatically. A draft can be felt at the heat exchanger outlets above the door, and the noise of the fan should be heard. Low draft may mean that the blower needs a clean, or that the intake is blocked. A blower which is faulty will probably allow the stove to get too hot, and then shut down.
A drop in stove performance could mean that the heat exchangers are being insulated from the airflow by a covering of fly ash, and need to be cleaned.
Is the stove output large enough to heat the area you're asking of it? Consider the current outside temperature and the effectiveness of your insulation.
An irritating pellet stove problem can be the amount of noise produced. You will be able to hear noise from the three motors, - combustion fan, convection fan and auger, as well as some airflow noise and the occasional pellet dropping. On a new stove, these noises will be at acceptable levels and most people can 'tune them out'.
As time goes on, and the stove gets older, new noises can emerge. Pellet stoves being mechanical devices, these will be mostly associated with parts of the stove being caused to vibrate by the motors, or the motors themselves.
Try to find out what's vibrating by pressing on the panels to see if the noise lessens in one particular place, and when you've found the culprit, tighten it up if you can. An old mechanic's trick is to take a length of dowel rod and press it to the suspect part, with the other end to your ear. This helps to pinpoint the source of the noise.
Dirty glass can occasionally be a pellet stove problem, and there are four main reasons why it can occur. Firstly, and favourite is a clogged burn pot causing a dirty flame.
If there is an air leak from the door or ash pan, this too can cause a dirty flame. See above. A tip to make sure that the door is sealing well is to close it on a piece of paper. If the paper holds in position, the seal is good.
The air wash holes, (if your stove has an air wash system), can get blocked with ash. These holes tend to be small and a vacuum cleaner is the best way to clean them.
Poor quality pellets that don't burn cleanly can be a major cause. It's best to burn a trial bag before investing in a ton.
A smell of smoke indicates a leak in the venting system. Make sure that all joints are tight and sealed with high temperature silicone sealant.
Now that you've identified the problem and know what you need to fix it, you might like to visit pellet stove parts. Do remember that you're dealing with fire, mains electricity and a powerful mechanical device. Proceed with safety in mind at all times. If you don't feel qualified or don't have enough experience, get someone else to help.
Causes of Pellet Stove Fires
Pellet Stove Cleaning
Warm Ash Vacuums
Pages Related to Pellet Stove Problems