Nortec GS Series GSP Indoor, Engineer'S Manual

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10-40
Page 33
2008-10-01
(e) Blower speed rotation must to be monitored to ensure proper control of input
modulation. System will lock out gas valve operation if proper blower speed
is not detected.
(f) A secondary combustion air safety, in addition to blower speed monitoring,
utilizing a mechanical pressure differential switch, must be used with each
blower to ensure combustion air is entering the pre-mix blower properly.
(g) Modular heat exchanger shall be easily removable through unit sidewall.
(h) Removable cover at front of unit facilitates easy cleaning (when applicable)
with complete access to tank and heat exchanger surfaces.
(6) Automatic water level control within a separate float chamber, isolated from the
boiling action, to prevent false water level indication.
(a) Fill rate must modulate to match capacity demand to ensure consistent
output. Fill cycles based on low water only is not acceptable.
(b) System shall fill through the bottom of the tank to reduce steam-quenching
effect and noise level. Filling at top of the tank is not acceptable.
(c) Unit water level is to be continuously monitored with a dual magnetic
electronic float system, located outside of the boiling water to ensure
accurate water level control and reduced maintenance. Cool fill water is to be
supplied into the sensing chamber to keep the device cool. Systems using
conductivity probes or floats located within hot reservoir water are not
acceptable.
(d) Tank and float chamber to be separated with a minimum of 1" (25 mm) rigid
insulation, minimizing potential scale build up on float mechanisms, due to
heating of the contained water.
(e) Humidifier shall have a dual fill valve to feed water to the tank and float
chamber, to reduce scaling and mineral build up on the magnetic floats.
(f) Float chamber to include LED indication of five possible water level
indications.
(g) Ongoing self-diagnostics including periodic float operation and fill/drain rate
verification.
(h) Positive drainage/blow-down using a drain pump, drawing water from the
bottom of the tank, maximizing mineral evacuation (when applicable).
Skimmer not acceptable.
(i) Blow down interval shall be based on actual steam production, and must be
adjustable to compensate for all water conditions, to ensure maximum energy
and maintenance efficiency.
(j) Pre-cleaning flushing feature shall be provided to reduce maintenance time.
(k) Must include end of season blow-down feature to evacuate contained water
and minerals after 72 hours with no demand for humidification.