Bosch UL-S · package boiler ·Front / burner door

How hot is a Bosch boiler front door?

On the surveyed Bosch boiler the front door measured 96 °C and the burner flange around the throat reached 146 °C — FLIR-measured, bare. The door also hinges open for burner service.

FLIR-measured surface temps CAD areas × 1.4 bolt/irregularity ISO 12241 · v = 0.5 m/s
How hot is a Bosch boiler front door — bare, FLIR-surveyed, 3D model How hot is a Bosch boiler front door — with Inzonex modular insulation, 3D model Bare · up to 146 °C Insulated · ≤45 °C
Drag-free toggle. Visible in this view: front (boiler) door (96 °C) and burner flange (146 °C) — bare.3D model: Inzonex · equipment rights belong to the manufacturer
Peak surface
146 °C
Bare, FLIR-measured
Largest loss
2.5 kW
Front (boiler) door
This view, bare
4.3 kW
2 element group(s)
After insulation
≈95%
Surface drops to ≤45 °C

Figures are for one boiler. Surface temperatures from a real FLIR survey of a UK commercial boiler house; CAD surface areas uplifted ×1.4 for bolts and irregular geometry; ISO 12241 steady-state (50 mm core, ambient 28 °C, air movement 0.5 m/s).

What you are looking at

How hot is a Bosch boiler front door

The front of a Bosch package boiler is large, hot and movable — the three properties that defeat rigid insulation. The door runs at 96 °C over a 2.3 m² face and the burner flange at 146 °C, yet both have to open for burner service.

A buttoned removable panel is made to the door and hinges with it: insulated when closed, out of the way when open. The burner mounting and sight port stay clear.

Element (this view)Temp °CArea m²Bare WInsulated WSurface °CCut
Front (boiler) door962.332,53015030−94%
Burner flange1460.851,7806030−97%
Front / burner door, per boiler3.184,310210≤45−95%

ISO 12241, 50 mm Inzonex modular core, ε(bare)=0.9, ε(jacket)=0.85, hconv at 0.5 m/s. Insulated figures are conservative steady-state, not best-case.

Element by element

Why each one is left bare — and how it gets insulated

Front (boiler) door · 96 °C · 2.5 kW bare

The front door carries the burner and closes onto the furnace tube — a 2.3 m² face the FLIR survey measured at 96 °C. It hinges open for burner service, so a fixed jacket fails here; a buttoned removable panel insulates it and opens with the door.

Burner flange · 146 °C · 1.8 kW bare

The burner mounting flange ran hottest on the front at 146 °C — a concentrated ring of loss around the burner throat. A shaped removable collar insulates the flange while leaving the burner and sight port clear.

Geometry that re-opens for access is the core idea behind the Inzonex modular design.

Materials & standards

What the cover is — and what it meets

Every surface on this view is covered by an Inzonex modular removable panel: a PAROC stone-wool core (50 mm) in a silicone outer shell — or a more durable PTFE shell as an option. The form-fitting build unbuttons for access and refits after each maintenance cycle. The outer surface drops to a touch-safe ≤45 °C.

ISO 12241 heat-loss methodISO 13732-1 ≤45 °C touch-safeEN 13501-1 reaction to fireASTM C680 heat-loss method

Industries that run this boiler

Brewery & beverageFood processingDairyChemical & petrochemicalPharmaceuticalPower & CHPOil & gas / refiningCommercial laundry
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FAQ

Quick answers

How hot is a Bosch boiler front door?

FLIR-measured at 96 °C bare over a 2.3 m² face; the burner flange beside it reached 146 °C.

Can the burner door be insulated if it opens for service?

Yes — a removable panel hinges with the door, insulated when closed and clear of the burner mounting and sight port when open.

What surface temperature after insulation?

About 30 °C — below the 45 °C touch-safe threshold — roughly a 94% cut in loss.

More of this boiler

Other surveyed views

Every face of the Bosch UL-S model has its own measured surfaces. Explore them from the 3D hub.

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