Gasmaster GMI 2M, Installation, Operation And Maintenance Manual

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IOM GMI 2M & 2ML Nov 2010.doc
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1.1 Boiler/Water Heater Description
The Gasmaster GMI 2M (2ML) is a gas-fired water tube boiler and water heater with nominal
input rating of 2,000,000 Btu/hr. Each unit has five stainless steel coiled tubes (SA-249 Type
316L), 1.25” (1.50”) diameter and 0.065” wall thickness. All five coils are held parallel vertically
by means of four stainless steel ready rods and adjustment nut assemblies. In between the coils are
four mesh rings which act to increase the performance of the heat exchanger. The heat exchanger
is fastened to supporting angle frame. The inlets and outlets of the coils are welded to the
manifolds pipes of the boiler. On the inlet manifold assembly, in between the coils and the
manifold are the purge valves.
The rest of the heat exchanger is a refractory assembly welded to hub on the rear coil and the
burner assembly connected to the front hub. The refractory assembly consists of a ceramic
refractory, insulation plate and support ring prevent hot gas escaping through the rear coil. The
front hub and the front coil are connected and support a high performance gas burner. The weight
of the burner is counter balanced by the heat exchanger.
The exact mechanism of heat exchange is a complicated engineering phenomenon, involving
combination of flow, temperature, fouling factors, and two-phase conditions. However, the
working of heat exchanger is a simple process. The gas burner ignites the gas and air inside the
combustion chamber (the central space of the five coils). The hot gas particles cool and condense
as they pass through the gaps of the coils. The flue particles are gathered in the boiler chamber
(space outside the coils and within the liners) and exit through the chimney. The water flows in
the opposite direction of gas. Feed water enters the each coil at the perimeter of the heat
exchanger. The water picks up heat gradually as it circulates through the coil tubes and exits at the
center (near the central hubs). The counter flow design reduces the impact of thermal shock and
increases the heat exchanger life. The flue condensate is drained through a fitting at the bottom
right of the boiler.
The boiler is designed for flue gas condensing for the high energy and a higher thermal efficiency.
Flue condensation will occur if the temperature of the inlet water is below dew point, usually 120
degrees Fahrenheit. Because the flue condensate is a corrosive element, the internal structure of
the boiler is constructed out of stainless steel 304/316L or better to offer the highest service life.
Corrosion related failures are the typical problems which can be managed through a scheduled
progressive inspection and maintenance program. Lastly the condensate and the flue venting
should be safely processed to the environment according to local jurisdiction and building codes.
1.2 Control System
The boiler/water heater control module consists of an “Individual Boiler/Water Heater Control
Module”, or the “BMS” (Boiler Management System) signal input module as an option.
With the “Individual Boiler/Water Heater Control Module”, the unit’s operation is governed by the
desired outlet (hot water) temperature. Using a digital, high precision temperature controller, the
owner will identify the required hot water temperature. A temperature sensor installed on the
boiler/water heater outlet manifold continuously measures the outlet water temperature. A
servomotor controlling the gas butterfly valve and the air damper (by means of a variable profile