Casablanca Fan Company HM 71 Description, Standard equipment, Outer body, Combustion gas circuit

DESCRIPTION

OPERATING PRINCIPLE

The HeatMaster is a high performance, direct fired hot water storage heater, which has indirect heat transfer due to its Tank-in-Tank construction.

At the heart of the HeatMaster is a stainless steel cylinder through which the flue tubes pass. This is surrounded by a mild steel shell containing the primary water (neutral fluid). The outer shell extends down to the combustion chamber and even around the flue tubes. The area of the heat transfer surface is therefore much greater than that of standard direct fired water heaters.

A circulating pump fitted to the primary circuit moves the water around the tank, heating it faster and maintaining an even temperature across the primary jacket.

The burner, either gas or oil, fires onto the primary water which indirectly heats the stainless steel cylinder containing the DHW. As with all Tank-in-Tanks, this is corrugated over its full height and suspended in the HeatMaster by its hot and cold water connections.

The cylinder expands and contracts during use and this, together with the fact that cold water does not come into contact with the intense heat of the burner flame, means that limescale buildup is prevented.

This scale resistant feature, along with the corrosion resistance of stainless steel, eliminates the need for sacrifical anodes.

The HeatMaster has one very major advantage over other direct fired water heaters - because it heats the DHW with a primary circuit, this primary water can be used to provide central heating as well.

By connecting two, three, four or more HeatMasters together in a module, most hot water and heating demands can be met.

Indeed, when used in conjunction with HR and Jumbo hot water storage tanks the Heatmaster can supply even the largest hot water requirement.

Standard equipment

The HeatMaster 71/101 has the following items as standard :

-On/off switch

-Summer/Winter switch

-MCBA controller, incorporating

•electronic control and high limit thermostats

•burner modulation

-primary circulating shunt pump

-primary expansion vessels

-primary safety valve

-pressure and temperature gauge

-drain valve

-body completely insulated in rigid polyurethane foam

CONSTRUCTION FEATURES

Outer body

The outer body containing the primary fluid is made of carbon steel (STW 22).

TANK-IN-TANK heat exchanger

The ring-shaped inner tank with its large heating surface for producing domestic hot water is built of Chrome/Nickel 18/10 stainless steel. It is corrugated over its full height by an exclusive production process and entirely argon arc welded by the TIG (Tungsten Inert Gas) method.

Combustion gas circuit

The combustion gas circuit is paint protected and comprises:

• Flue pipes

HeatMaster 71/101 models contain 8 steel flue pipes with an internal diameter of 64 mm. Each pipe is fitted with a turbulator of stainless steel designed to improve heat exchange and to reduce flue gas temperature.

• Combustion chamber

The combustion chamber on HeatMaster models is entirely water cooled.

Insulation

The boiler body is fully insulated by rigid polyurethane foam with a high thermal insulation coefficient, sprayed on without the use of CFCs.

Casing

The boiler is covered by a steel casing which has been scoured and phosphated before being stove enamelled at 220 °C.

Burner

71 and 101 models are always delivered with ACV BG 2000-M 71 and 101 air/gas premix burners.

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