St Croix Pellet Stove Keeps Over Feeding

What is the underlying issue with all St. Croix stoves and how can you make sure to get the most out of your investment?

St Croix didn't start out making pellet stoves....all of their stove designs were originally designed to burn corn, and that is the underlying problem...corn burns differently than wood. Wood pellet stoves require ash removal and the places where the ash collects need to be accessible.

Ash that cannot be seen by the user is most often overlooked and not cleaned. The owner's manuals do a very poor job of explaining where to look and what to do when maintaining the stove. Failure to properly maintain the stove causes creosote in the firebox, filthy glass, and failure of vital components.

Below are some tips to help you maintain and troubleshoot your St Croix pellet stove.

Cleaning Out Your Stove Properly

There are four main areas of each pellet stove or insert that need to be cleaned out; the heat exchanger, the burn pot and vers-grate, the ash traps and passages behind the firebrick and the exhaust manifold from the firebox to the combustion blower.

Aside from the daily and weekly tasks of general ash removal, a complete cleaning of the four main systems should be done once a month or after every 50 bags. To get the heat exchanger, remove the firebox baffle. To get to the ash traps and air passages, remove the firebrick and tap on the back walls with a hammer while vacuuming out the ash traps. To clean out the versa-grate the entire burn pot needs to be unassembled, scraped and vacuumed. To clean out the exhaust manifold you may need to remove the combustion blower and vacuum the passage from the opening to the firewall. Freestanding models made after 2011 will have an access door in the ash pan area. Remove the ash pan and you'll see the access panel on the back wall if you have it on your model.

Maintenance for the Versa-Grate Motor and Assembly

St Croix stoves were originally designed to use corn which burns very differently than wood pellets.  Corn does not produce very much ash and has lots of sugars and moisture that reduce down after burning to form a "clinker".

This is where the stove design is flawed. When burning corn, you can have very narrow air passages within the stove and be okay because corn doesn't create as much ash as wood. And that's why these stoves are so darn hard to clean and keep clean.

In order to burn corn for extended periods of time, there needs to be a mechanism to move the clinker in the burn pot or it will stick and obstruct air flow. To achieve this, St. Croix implements a system they call the "Versa-Grate". The bottom of the burn pot actually moves back and forth at its base, constantly pushing the clinker around to prevent sticking. Once a day the stove needs to be shut down, have its clinker removed, and then restarted. St Croix made the decision that the Versa-Grate system would be carried over to the wood pellet designs where agitation isn't required. Agitation isn't required because of how the air is delivered into the burn pot, the versa-grate is still there, but the air holes were modified to burn wood.

 In general, the overwhelming problems owners have seem to stem from one of two causes; either there is too much ash in the stove and its clogged up or the versa-grate motor burns out and causes the stove to become clogged up, sometimes both happen simultaneously. Besides that, these pellet stoves seem to exhibit about the same rate of repair as anything else. The components in these stoves are built remarkably well.

If the stove has power and the controller is "ON", the versa-grate should be working. All St. Croix pellet stoves must have a functioning versa-grate system for the stove to burn properly. The versa-grate assembly is available as an entire kit through our website but has a few different configurations depending upon your year and model. I would suggest not to replace any singular part of this system; if any part of it is worn out, replace it all.

There are maintenance tasks owners can undertake which will extend the overall life of the versa-grate system found on St. Croix pellet stoves.

• The off-set cam on the end of the versa-grate motor shaft must be lubricated with a high-temp anti-seize lubricant after each ton of fuel that is burned. Simply brush on a generous amount on the top of the cam and it will lubricate itself as it turns.

• The stator cap on the top of the versa-grate motor should get 3 drops of non-detergent SAE30 oil every 6 months of continued use. We recommend Anderol 465 for all motor bearings.

• Excluding their inserts, St. Croix pellet stoves have an area that is impossible to clean their ash from, this area is located forward of the burn pot where the igniter is located. The bottom of the burn pot, the part that attaches to the versa-grate push rod has a thickness to its height at the point where it attaches to the rod. As the push rod goes back and forth, if ash is not shaken down or vacuumed out regularly, the burn pot grate will, in effect, "plow" the ash into this unseen area. If this area is not cleaned the ash will compact so hard that one needs to chisel it out…it is at this point that resistance is working against the versa-grate system and a component will fail. This system is only a problem because nobody seems to know it's happening until it's too late, this is why most owners send their St. Croix pellet stoves to the pot when the versa-grate system fails.

Feed System Parts

Overall, St Croix has done a great job in designing their feed system. The parts consist of an auger motor, a lower plate with bushing, motor retaining clip, lock collar, Belleville washer, auger, and upper flange bushing. The auger motor is a 2 RPM clockwise rotating motor with a cooling fan, this motor can last a decade or more if proper maintenance is carried out.

• The gearbox of the auger motor should never need anything. The stator cap should be lubricated with Anderol every 6 months of continued use.
• As with any pellet stove, at least once a month the stove should be allowed to run out of fuel so the dust can be vacuumed out of the hopper. Dust (fines) that are allowed to gather at the base of the hopper will cause a problem if left unattended. When you have a collection of fines in the hopper a pellet stove can become difficult to run on low heat levels and will often have a hard time starting on it's first to try, this is because the pellets will be restricted from entering the auger flighting. Fines in the hopper don't feed through the system very well and occupy the opening area at the base of the hopper.
• Additionally, if fines reside in the hopper for long stretches of time, they will eventually become trapped between the auger shaft and the bushing. When this happens, the bushing will often freeze itself to the auger shaft and break away from the plate it is mounted to, this creates a lot of resistance against the auger motor. Owner and technicians should check on the status of the bushing each year and if it's moving around with the shaft, make sure to replace the bushing and the mounting plate.
• A minimum of once a year, you should inspect the mechanical cabinet and look directly under the auger motor for wood dust that is gathering in a pile. It will be a little at first but I have seen a pile of dust 10 inches high covering every component. If you see any wood dust at all, replace the auger bushing a plate, ASAP.

Failure to notice these parts wearing out, especially on the St. Croix York Insert, can have a very dangerous outcome… your house could actually burn down. I have witnessed, first hand, on more than 3 occasions, a St. Croix York Insert spitting out embers and flames from the heat exchanger on to the combustible floor in front of the stove.

A few things to know about the feed system are; the Belleville washer that goes between the plate bushing and the auger needs to be there and needs to be cone side up. The auger motor retaining clip, if the auger motor is properly seated into the auger shaft, should clip over the two mounting corners firmly. If you have to stretch it or bend it in any way to get it to fit, the auger motor shaft is too far out from the collar set screw. As with any pellet stove that uses a "top and drop" feeding method (pellets rise in the hopper and then fall into a burn pot) if there is ever a burn back into the hopper, the entire feed system should be replaced prior to returning a stove back into service.

Follow these tips and your St Croix pellet stove will continue to burn safely, and your fire just as strong as when you first used it!

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Source: https://pellet-stove-parts-4less.com/blogs/all/fixing-common-problems-with-st-croix-pellet-stoves

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