Enviro Empress FS Pellet Stove - Vacuum code resolution in step by step detail

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New Member
Dec 31, 2023
Dunstable, MA
I'm new to the pellet stove world, but very handy. After about a year, my stove started running very rich and sporadically, and then it wouldn't fire up altogether. It would shut down after 30 seconds, and the second heat light would flash. I figured out pretty quickly that it was a vacuum issue, but the manual was not very helpful from there. Then I hit the blogs, and while helpful, the specifics on the order of solutions were lacking, with some saying replace the $400 mother board, or the fan, or the vacuum switch, etc. So I wanted to share my story and specifically detail how I resolved my issue for free in about an hour.

The system has a fail safe in the form of a vacuum switch, which measures the efficeincy of the air flow, from intake to exhaust. If the intake is poor, or the exhaust is clogged, the vaccum line will not have enough vaccum to allow the vacuum switch to function. Without the vacuum switch being satisfied, the system shuts down to avoid a dangerous CO2 condition.

The manual does not adequately specify the maintenance requirements. So one would not know that there is a catch basin leading up to the exhaust outlet that catches ash. This is where the vacuum line feeds into. There are two small access panels on each side to clean out the catch basin. You also want to remove the side stone panels to get at it from above. You do this by removing the two metal brackets on each side inside the chamber, each has two screws. Then the two side stone panels jimmy right out. Then you'll see the catch basins from above. Take a 3/4" rubber hose a couple feet long and stick it in your shop vac head and snake it into the channels from up high and from the side access ports, sucking out the ash as much as you can. Do this at least once per year. Make sure there are no obstructions in your exhaust pipe/chimney. Then remove the side access panel below the control panel, and you'll see an orange 1/4" rubber hose. That is your vaccum line and it runs from the exhaust duct down low to the vacuum switch up high and to the right. Make sure the nipple attached to the exhaust duct is firm; they get squirrelly. Take the hose off the vacuum switch up high and blow air through it. If you cannot blow air, remove the hose and make sure it is clean and bore out the barb at the exhaust duct with a paper clip.

If this does not solve your problem, then you need to go to greater measures. Step one is to check the seals at both the locking door and ash tray. These need to be solid to create vacuum. If those seem fine, unplug the wires to the vacuum switch and jump them together. This bypasses the switch PURELY FOR THE PURPOSE OF SEEING IF THE SWITCH IS THE PROBLEM. Unless you want to die or kill your family, don't run it with a bypassed switch. Try to fire up the stove. If that is not the issue, the next suspect would be the convection fan. If it is not running up to capacity, there will not be enough vacuum to satisfy the vacuum switch. This is one of those items that pays for itself getting a fresh one in, so replace it. Maximum effieincy requires a strong fan and with all the heat, the fans get squirrelly before it is obvious. The last resort is the mother board.

Too many people have you buying parts to troubleshoot. Many of them sell parts for a living, You're better off hiring a professional than just replacing chit, at least you have recourse if their fix doesn't work.

Hope this was helpful to someone.
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So what eventually was the problem?
Also once a year remove the combustion fan
and clean behind and also the air gate to the back of the stove
Make sure that the gate moves from fully open to fully closed after a full cleaning