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Document: GFH-NT 1500-4000 IM 14 DEC 2016
Gas Fired Heater Instructions
©2016 NOVATEC, Inc. All Rights Reserved
3.0
ADJUST HIGH GAS PRESSURE SWITCH (HGPS)
3.1
The HGPS is open if the main gas pressure is low. The switch should be adjusted to
36" WC. The neon indicator will glow (visible through the clear plastic cover on the
switch) when the switch is closed.
4.0
ADJUST PROOF OF CLOSURE SWITCH (POC)
4.1
The POC switch should be in the NO position (orange neon indicator light on) when the
main safety shutoff valve is closed. When the main safety shutoff valve is open, the
POC switch should be in the NC position (green neon indicator light on). With the main
safety shutoff valve closed, remove the clear cover on the POC. Turn the white knob
counter clockwise (CCW) until it comes to the stop. The circuit between the terminal
COM and NO should be open. Then turn the knob slowly cw until the switch makes.
Make sure the POC is working properly before putting the valve into service.
5.0
ADJUST COMBUSTION AIR STATIC PRESSURE
5.1
Connect a manometer to tap A. (Reference SK-946A)
5.2
Adjust the damper on the combustion blower discharge to achieve the static pressure
(± 0.5" WC) as shown in the Engineering Data section under Instrument Settings.
5.3
Lock the damper in place.
6.0
ADJUST MAIN GAS STATIC PRESSURE
6.1
The flame is on for this setting.
Connect a manometer to tap B. (Reference SK-
946A)
6.2
Adjust the main gas regulator to achieve the static pressure (± 0.5" WC) as shown in
the Engineering Data section under Instrument Settings.
7.0
FLUE ANALYSIS
7.1
The flame is on for this test.
With a combustion analyzer, measure the oxygen
content of the flue exhaust. It should be greater than 0% when the automatic main gas
valve is fully open. When the burner is at set point with little modulation of the
automatic main gas valve, the readings are typically in the 1 to 16% range. Good flue
analysis and performance is achieved by balancing the combustion air and the amount
of gas. Small adjustments should be all that is required if all the parameters are within
a normal range.
Proof of Clos ure
(POC) Switc h
Pos ition Indic a tor
Photograph,
Typical Proof of
Closure (POC)
Switch and
Position Indicator
