Lennox HVAC Unit LGT240H5M

Check with gas company or authorities for local code requirements

Refer to the LGT Installation, Operation and Maintenance instruction

Turn off power before removing access panel or cleaning blower wheel

Inspect supply air blower wheel for accumulated dirt or dust

Clean the blower wheel if dirt or dust is present

Check with gas company or authorities for local code requirements

Refer to the LGT Installation, Operation and Maintenance instruction

Move test gauge to the outlet pressure tap on unit gas valve GV1 and/or GV3

Verify manifold pressure is factory set

If manifold pressure is incorrect, replace the valve

Check with gas company or authorities for local code requirements

Refer to the LGT Installation, Operation and Maintenance instruction

Connect test gauge to the inlet pressure tap on unit gas valve GV1 and/or GV3

Record the gas supply pressure with unit firing at maximum rate

Is the gas supply pressure within the acceptable range?

Check each unit separately while operating at maximum rate, starting with the one closest to the supply gas main

Verify local code requirements with gas company or authorities

Check for ETL/CSA design certification on all LGT units

Measure pressure drop between the gas meter and the unit

Is the pressure drop less than or equal to 0.5”W.C.?

Ensure supply gas pipe is not smaller than the unit gas connection

Refer to LGT Installation, Operation and Maintenance instruction for more information

Check with gas company or authorities for local code requirements

Refer to the LGT Installation, Operation and Maintenance instruction

Connect test gauge to the outlet pressure tap on the gas valve

Start the unit and call for second stage heat

Wait five minutes for the unit to reach steady state

Observe the flame stability and color

Compare manifold pressure to values in TABLE 24

Disconnect heating demand after obtaining accurate reading