Technical data

EM RANGE GAS FIRED
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can be commissioned. A fan overrun facility
must have been programmed into the fan
controls so as to allow for residual heat to be
dissipated at the end of a heating cycle.
Failure to provide this facility will result in
frequent overheat situations which over
prolonged periods can compromise the
longevity of the EM unit and its controls. The
residual heat can also damage the flue system.
Further, if fire dampers are fitted within the
ducting these can be activated by the residual
heat if insufficient fan overrun time has been
allowed for and programmed in.
Note
In applications where fire alarm systems are
integrated with the AHU/EM controls it should
be noted that when these fire systems are
activated they usually cut power to the AHU
and EM unit resulting in residual heat build up
(when activated during a heating cycle or within
the fan overrun time). This will cause overheat
situations and can also activate duct mounted
fire dampers. Frequent overheat situations can
compromise the longevity of the EM unit and its
controls.
It is a requirement that only suitably qualified
and competent personnel are allowed to
undertake the commissioning of the appliance. It
is also strongly recommended that prior to
commissioning the engineer familiarises himself
with the information contained within the
information pack that accompanies the EM unit,
the EM unit/air handling system itself, and
becomes familiar with the specific
installation/application. The following checks
should be carried out after the familiarisation
process.
Warning
All EM units undergo a rigorous test programme
prior to being despatched, whilst such a
programme does involve pre-commissioning
and setting up the EM unit to operate within its
designed operational limits, this does not mean
that on site commissioning is less important than
might otherwise be the case.
4,1 Commissioning - Pretest
The air system and controls must have been
commissioned and proven prior to
commissioning the EM unit.
Check to ensure electrical safety, and inspect
and purge the gas train installation, testing for
soundness.
(a) Ensure that the electrical supply is turned
off
(b) Ensure that the gas supply is turned off
(c) Check that all panels and fasteners are
secure and in place
(d) Check that the EM and air handling unit is
installed so that it is square and that the support
is adequate
(e) Ensure that warm air delivery outlets are
open and that ducting is adequately supported
(f) Ensure that if filter assemblies are fitted that
they are secure and correctly located
(g) Check that air inlets are clear and that return
air paths are adequate
(h) Ensure that the flue is secure, adequately
supported, and that the various joints are
properly sealed
(i) Check that condensate trap and drain
facilities are adequate
(j) Check that there is provision for flue gas
sampling and that this sample point can be
plugged and sealed after commissioning
(k) Check that fan and limit stat settings have
not been disturbed
(l) Ensure that the burner is securely attached to
the EM unit
(m) Test for electrical earth continuity between
the appliance, gas pipe work, and mains supply
(n) Turn the main electrical supply to on, select
the following settings (it should be noted that as
the controls package is usually supplied by
others the actual settings may vary from those
detailed as follows, the rationale is to check that
airflow characteristics are in accordance with
those detailed previously)
on/off - on
heat/ventilation - ventilation
manual/automatic - manual
The fan will start enabling the airflow direction
etc to be verified
(o) Check that the volumetric air flow over the
combustion chamber and heat exchanger is as
recommended and is sufficient to satisfy the air
pressure switch. On completion of airflow tests
reset on/off switch to the off position
(p) Set room thermostat and time clock to on
positions
(q) Turn mains electrical supply to off