Vermont Casting 1990CE Catalytic Combustion System Inspection and Cleaning

Intrepid II Woodburning Stove

The Catalytic Combustion System

Inspection and Cleaning

This wood heater includes a catalytic combustor, which needs periodic inspection and replacement for proper operation. In the United States, it is against the law to operate this wood heater in a manner inconsistent with the operating instructions in this manual, or if the cata- lytic element is deactivated or removed.

Under normal operating conditions the catalytic element should remain active for two to six years (depending on the amount of wood burned). However, it is important to monitor the combustor periodically to ensure that it is functioning properly as well as to determine when it needs to be replaced.

A probe thermostat, passing through the back of the stove into the catalytic combustion chamber, automati- cally regulates the catalytic combustion air supply. Deterioration of the probe may result in decreased catalytic combustor performance.

A poorly-functioning catalytic combustion system will result in a loss of heating efficiency, and an increase in creosote and emissions.

The combustor should be visually inspected in place for fly ash accumulation and physical damage three times per year. Do not remove the combustor unless a more detailed inspection is warranted because of diminished performance as outlined below, or to inspect the probe thermostat.

The refractory package that houses the catalytic com- bustor should be inspected annually for a buildup of flay ash, and cleaned if necessary. This may be done during examination of the combustor.

The probe thermostat should be inspected annually, or more often if decreased catalytic combustion perfor- mance is not due to a defective combustor.

When to Suspect a Combustion

System Problem

The best way to evaluate the performance of your In- trepid II’s combustion system is to watch the amount of smoke leaving the chimney - both when the combustor has achieved “light-off” and when it has not. Follow this procedure:

With a fire going and the combustor activated, with the damper closed to send smoke through the combustor as described in the Operation Section, go outside and watch the smoke leaving the chimney.

Then, open the stove damper and again watch the smoke leaving the chimney.

You should see significantly more smoke after the sec- ond step, when the stove damper is open and smoke does not go through the combustor. However, do not confuse smoke with steam form wet wood; steam dis- appears rapidly in the air, smoke does not.

If this test indicates a problem, consider other possible factors as well, such as the time of year or a change in the quality of your fuel. In spring and fall, draft is weaker than it is during colder winter weather, and fires can burn sluggishly. Small, hot fires are a good solution under these conditions.

“Green” (insufficiently seasoned) wood will burn more poorly than properly seasoned fuel. You may have to run your stove hotter (with more primary air) to achieve good performance if you are burning green or wet wood.

Also, consider any changes in your burning routine.

Once you have ruled out any other possible causes for decline in performance, you may inspect the combus- tor and probe. Wear a dust mask, safety glasses, and gloves. Refer to Figure 32 as a guide.

1.Remove the andirons.

2.Reach inside the stove with a pair of pliers and turn the two clamps that hold the fireback 90°. Turn the left clamp clockwise, and the right clamp counter- clockwise.

3.Grasp the fireback by its vertical ribs and remove it, together with the attached throat hood. Pull the left side out first.

4.Carefully clean the left and right exhaust pockets of the refractory package. Use a shop vacuum, ideally one with a very fine filter, and be careful to avoid damaging the refractory material. This material can stand high temperatures, but it is somewhat brittle physically.

5.Carefully remove the refractory access panel in front of the catalytic element.

6.Gently slide the catalytic element out of the refrac- tory chamber. Check the element and the bottom of the chamber for a buildup of fly ash.

7.If the catalytic element is clogged, take it outdoors for cleaning. Blow gently through the honeycomb. A large amount of fly ash may come out of the ele- ment.

8.Inspect the element. Although small hairline cracks will not affect performance, the element should be largely intact. If the element is broken in pieces or has large sections missing, replace it. Call your dealer for a replacement element, part no. 160- 2521.

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