Description Of Appliance; For Whom Is This Manual Intended - andrews COMBIflo 100/300 Installation, Operation And Maintenance Manual

1.1 DESCRIPTION OF APPLIANCE

Th is Andrews COMBIfl o is a gas fi red, low No×, multi-heat engine cascading boiler system, with an integrated
5" Low Loss Header for the supply of a low temperature hot water space heating system. Th e COMBIfl o range
of appliances also features an integrated stainless steel tank and plate heat exchanger for the supply of hot
water.
Fully automatic electronic controls are integrated into the appliance, with a wide range of control and sensor
options available. Th e controls also provides voltage free outputs for Enable, Burner On, Fault and 0-10V input
for remote BMS use.
Access to the controls of the appliance via the internet and/or mobile phone app, is available through an
optional device from Andrews Water Heaters.
Each heat engine module consists of a stainless steel combustion chamber, premix burner, modulating fan, gas
valve, ignition and fl ame detection electrodes and a NTC fl ue sensor for safety supervision.
Each heat engine module is equipped with NTC sensors for precise temperature control on fl ow and return
manifolds. Fully premixed, radiating, modulating burner, integrated with gas valve to deliver precise gas/air
mixture throughout the full modulation range.
Common combustion air intake manifold, takes air from boiler room (type B23 fl ue) or directly from outside
via a combined fl ue system (C13 & C33). An air control non-return fl ap is integrated into the air supply of
each heat engine, to ensure that fl ue products cannot contaminate the air supply, when a heat engine is not in
operation.
Th e safety and operation functions of each heat engine are managed by micro processor controlled circuit
boards, one for each heat engine. Th e upper controller also acts as the cascade controller, switching/modulat-
ing the heat engines according to the demand and data from the systems sensors. Control is performed using
comparison parameters between the requested temperature and the global fl ow temperature.
control logic:
At full demand, each heat engine is ignited one at a time, until all heat engines are operating at full output.
As fl ow and return temperatures increase, all heat engines will begin to modulate down together, until all are
operating at minimum input rate. As fl ow temperatures begin to approach the calculated set point, one of the
heat engines will stop, leaving the others operating at minimum input rate. Th is will continue until all heat
engines have stopped and temperature fl ow requirements have been fully satisfi ed.

1.2 FOR WHOM IS THIS MANUAL INTENDED?

Th is manual is intended for the heating specialist who installs commercial/industrial heating plant and equip-
ment.
ANDREWS COMBIfl o DRAFT 2 GB/IE