Daikin MPS015 F, Installation And Maintenance Manual

Page: 28 / 132

Gas Pipe Manifold Pressure Adjustment for Natural Gas Fuel
For Two Stage Furnace
1 . Read gas pressure at the Inlet Pressure Tap of the
Honeywell VR8305Q Gas Safety Control Valve ( Figure
25 ) and confirm pressure is at 7.0" wc. Adjust upstream
pressure reducing gas regulator as required to obtain
7.0" wc gas pressure.
2 . The gas pipe manifold pressure for high fire
(stage #2) should be set at 3.2" wc. Adjust the
High Pressure Adjustment Honeywell VR8305Q
Gas Safety Control Valve ( Figure 25 ) as required.
Screwing the adjustment clockwise will increase
pressure; counter clockwise will decrease pressure.
3 . The gas pipe manifold pressure for low fire (stage
#1) should be set at 0.8" wc. Adjust the Low Pressure
Adjustment Honeywell VR8305Q Gas Safety Control
Valve ( Figure 25 ) as required. Screwing the adjustment
clockwise will increase pressure; counter clockwise will
decrease pressure.
For Modulating Furnace:
1 . Read gas pressure at the Inlet Pressure Tap of the
Honeywell VR8305Q Gas Safety Control Valve ( Figure
25 ) and confirm pressure is at 7.0" wc. Adjust upstream
pressure reducing gas regulator as required to obtain
7.0" wc gas pressure.
2 . The gas pipe manifold pressure for high fire should be set
at 3.2" wc. Adjust the High Pressure Adjustment on the
Honeywell VR8305Q Gas Safety Control Valve ( Figure
25 ) as required. Screwing the adjustment clockwise
will increase pressure; counter clockwise will decrease
pressure .
3 . The gas pipe manifold pressure for low fire (stage #1)
should be set at 0.25" wc.
Adjust the Low Pressure Adjustment on the Honeywell
VR8305Q Gas Safety Control Valve ( Figure 25 ) as
required until pressure at the Honeywell VR8305Q Gas
Safety Control Valve Outlet Pressure Tap reads 0.25"
wc. Screwing the adjustment clockwise will increase
pressure; counter clockwise will decrease pressure.
Adjust the Maxitrol M520B Modulating Valve (
Figure 26 )
Low Flow Adjustment screw until the gas pipe manifold
pressure reads 0.25" w.c.
Figure 25: Honeywell VR8305Q Gas Safety Control Valve Figure 26: Maxitrol M520B Modulating Valve
High Pressure Adjustment
Pressure Regulator Adjustment
(under cap screw)
Low Pressure Adjustment
ON–OFF Gas Control Knob
Outlet Pressure Tap
Inlet Pressure Tap
Low Flow Adjustment Tap
(right side)
Low Flow Adjustment Tap
(left side)
IM 1058-8 • MAVERICK II ROOFTOP SYSTEMS 28 www.DaikinApplied.com
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