Thermo Products CDX1-75N CHX Low CDX Low Model Series, Normal Manifold, Pressure in. W.G

All installations and services must be performed by qualified service personnel.

Figure 23: Outlet view of two-stage, automatic gas control valve

b.Using a 3/32-in. hex key (or Allen wrench), turn the inner adjustment screw clockwise to increase, or counterclockwise to decrease, the gas pressure (and gas flow) to the main burner.

c.Replace the cap screw and tighten it firmly to prevent gas leakage.

d.Referring to Table 5, measure the gas pressure and to confirm it has been adjusted to within the allowable range. Repeat adjustments (a) through (c), as required.

Table 5 Design Gas Pressures for each Furnace Model Series,

Operating Mode, and Type of Fuel.

Fuel Gas Type		Propane			Natural
Operating Mode and	High Fire	CHX Low	CDX Low	High Fire	CHX Low	CDX Low
Model Series		Fire	Fire		Fire	Fire
Normal Manifold	10.0 ± 0.3	4.8 ± 0.3	5.6 ± 0.3	3.5 ± 0.3	1.8 ± 0.3	2.0 ± 0.3
Pressure (in. W.G.)
Maximum Gas Supply		14.0			14.0
Pressure (in. W.G.)
Minimum Gas Supply		11.0			4.5
Pressure (in. W.G.)

13.Adjust the room thermostat so the burner will operate on high fire only.

NOTICE: There is a 30 second delay before the gas control will step up to high fire.

14.To obtain an accurate manifold gas pressure reading, the main burner must be cycled on and off several times to stabilize the gas control valve pressure regulator diaphragm.

15.Allow the burner to operate for at least 3 minutes before taking gas pressure readings.

16.Using a pressure gauge, measure the burner manifold gas pressure.

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