Thermo Pride CLHS1-050P36N Installation And Operation Manual page 39

All installations and services must be performed by qualified service personnel.
Check for the model number of this furnace, its input, the type of gas and the manifold pressure on the
information plate located on the vestibule panel behind the upper front panel. In the example above, if the
furnace was a CLHS1-100 model, then the 98,663 BTU input would be acceptable because it was within 2% of
the listed input of 100,000 BTU.
Make sure that the gas supply pressure to the furnace falls within the maximum range of 4.5" to 14.0" w.c.
pressure on natural gas and 11.0" to 14.0" w.c. on Propane gas. The pressure to the furnace must be checked
while the furnace burner and any other gas appliances on the same supply system are operating.
GAS PRESSURE CHART FOR ALL CHLS1 & CLHX1 MODEL FURNACES
Fuel Gas Type
Operating Mode and
Model Series
Normal Manifold
Pressure (in. W.G.)
Maximum Gas Supply
Pressure (in. W.G.)
Minimum Gas Supply
Pressure (in. W.G.)
This gas furnace is equipped with a fixed orifice sized for the manifold pressure shown on the information plate. The
input should only be increased or decreased by adjusting the manifold pressure. Remove the 1/8" threaded pipe plug
located on the manifold and connect a U-Tube manometer or pressure gage to measure the pressure.
To adjust the pressure, remove the brass regulator screw cover from the regulator on the outlet side of the gas valve
and using the adjustment screw. Refer to Figure 15, Two stage regulator shown. Decrease the pressure by turning the
screw counterclockwise or increase it by turning the screw clockwise. ADJUSTMENTS TO THE LISTED
PRESSURE MUST NOT EXCEED THE VALUES IN TABLE 4. Replace screw cover when adjustment is
complete. The correct input can be assumed if the furnace manifold pressure is the same as that shown on the
information label if a gas meter is not available for natural gas, or the unit is installed on liquefied petroleum gases
which are not metered.
Shut off the gas supply to the furnace. Remove the pressure gage and re-install the pipe plug using a thread
compound resistant to the action of Liquefied Petroleum gases. If the rated input cannot be obtained with the present
orifice at the correct pressure, your installer should contact Thermo Products to assist in sizing the proper orifice.
Propane
CLHX1
High Fire
Low Fire
10.0 ± 0.3 5.0 ± 0.3
14
11
TABLE 4
Figure 15
39
Natural
CLHX1
High Fire
Low Fire
3.5 ± 0.3 1.8 ± 0.3
14
4.5