Rear Sight Tube

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Rear Sight Tube

We cast durable rear sight tubes that provide operators with a safe visual path to monitor flame quality inside the active furnace without compromising thermal containment.

Get a Quote Order now (502) 459-9131

*These tiles are compatible with Cleaver-Brooks boilers.

  • 94-143
    Sight Tube
    36"
    CB
    15-40
  • 94-165
    Sight Tube
    48"
    CB
    50-100
  • 94-166
    Sight Tube
    60"
    CB
    125-200
  • 94-167
    Sight Tube
    78"
    CB
    250-350
  • 94-168
    Sight Tube
    96"
    CB
    400-800

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In-stock items. Order by 3:00 PM EST for Same-Day Shipping.

*Halmar Corporation offers many Cleaver-Brooks aftermarket parts. Halmar Corporation is not a factory authorized sales representative for Cleaver-Brooks, nor is Halmar Corporation affiliated with Cleaver-Brooks in any way. Cleaver-Brooks is a registered trademark of Cleaver-Brooks, Inc., Thomasville, GA.

Some aftermarket parts may be made by other manufacturers.

Can’t Find the Refractory Tile You’re Looking For?

We carry a large inventory and if we don’t have what you need, we can help track it down for you. Give us a call.

Get a Quote Call Us (502) 459-9131
Halmar staff finishing off a custom refractory throat tile

Frequently Asked Questions About Rear Sight Tubes

A boiler rear sight tube is a heavy-walled, tubular refractory component engineered to provide a safe, clear visual pathway through the boiler’s thick insulation lining. Its primary function is to allow maintenance technicians and operators to visually monitor the active flame quality, combustion patterns, and internal furnace conditions from outside the boiler shell without compromising thermal containment. By acting as a structural sleeve, it protects the viewing opening while shielding sensitive monitoring tools from extreme radiant heat and flue gas leakage.

The rear sight tube acts as a critical diagnostic window for system performance. When combustion byproducts—such as soot, fly ash, or refractory dust—clog the interior of the tube, it obscures the operator’s view of the flame core, making it impossible to perform accurate visual inspections during run-time. Furthermore, a buildup of debris can create a trap for moisture or corrosive agents, which may degrade the tube material itself over time. Regularly cleaning or verifying that the sight tube is free of obstruction is essential for maintaining safe monitoring practices and ensuring you can verify flame stability during every shift.

Sourcing specialty inspection components directly from factory original equipment manufacturers (OEMs) often exposes facility procurement managers to long supplier wait times, distributor shipping delays, and significant price premiums. Halmar functions as an independent, domestic manufacturer that controls the entire casting, curing, and dimensional quality-control process inside our modern Louisville, Kentucky facility. We maintain a deep, ready-to-ship stock of premium aftermarket boiler parts on our shelves, allowing us to deliver superior material density, precise dimensional alignment, and fast same-day shipping to minimize critical asset downtime and keep your furnace inspection routines on schedule.

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