Vermont Castings Defiant

Alignment Notches

Right Wedge

Left Wedge

 

Brick Guide

 

Brick Clip

 

Bricks

 

ST556

 

Fig. 37 Remove the bricks and the brick retainer.

Lower Fireback

ST557

 

 

Fig. 38

Remove the lower fireback.

 

3.Carefully remove the catalytic combustor’s refractory access cover, then remove the combustor. The refractory material is brittle; handle it carefully. (Fig. 39)

4.Check the combustor's honeycomb-like element for a buildup of fly ash. If any is evident, take the combustor outside and clean it by blowing air gently through it. Do not push anything through the honey- comb; do not use compressed air to clear the passages. Such abrasion can scrape the thin coating of platinum (the catalyst) off the ceramic base, shortening the catalyst's life and reducing its effectiveness.

 

Catalytic

 

Element

 

Catalytic Access

ST558

Panel

 

Fig. 39

Remove and inspect the catalytic element.

5.Inspect the element for damage or degradation. Although small hairline cracks will not affect perfor- mance, the element should be essentially intact. If the element is broken in pieces or has sections missing, it should be replaced. Call your local Vermont CastingsMajestic Products Company Authorized Dealer for a replacement element.

While the catalytic element is removed, check the condition of the secondary air probe. Use an inspection mirror to locate the probe within the combustion chamber. (Fig. 40) The probe should extend 1” to 1¹⁄₂” into the chamber and show no signs of excessive deterioration, such as warping, corrosion, or short length. A damaged secondary air probe can affect catalytic performance. If the probe needs replacement, contact your local dealer.

1"

ST559

Fig. 40 Use an inspection mirror to check the reflected view of the secondary probe.

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Vermont Casting 1910, 0968 installation instructions Remove the bricks and the brick retainer