Lennox International Inc GWB9-050IH-2, GWB9-075IH-2 Check OUT Procedure and Adjustment

CHECK OUT PROCEDURE AND ADJUSTMENT

Verify Proper Sequence Of Operation

Place boiler into operation and observe operation through several cycles. Follow remaining steps in this section to insure boiler is operating correctly.

First couple of cold starts may be rough due to gas line not being completely purged of air, causing low firing rate and high excess air levels.

Inspect Venting And Air Intake System

Operate boiler and verify all vent/air intake connections are gas-tight and watertight. Repair any leaks immediately.

Inspect Condensate Drain

Verify all connections are watertight, and that condensate flows freely. Repair any leaks immediately.

Test Other Safety Controls

If boiler is equipped with low water cut off, manual reset high limit, or additional safety controls, test for operation as outlined by control manufacturer. Burner should be operating and should go off when controls are tested. When safety controls are restored, burner should reignite.

Set Thermostat Heat Anticipator (If Used) And Verify Thermostat Operation

For single thermostat connected to yellow thermostat lead wires in furnished field wiring junction box, heat anticipator should be set at 0.7 amps. For other wiring configurations, refer to instructions provided by thermostat manufacturer regarding adjustment of heat anticipator. Cycle boiler with thermostat. Raise thermostat to highest setting and verify boiler goes through normal start up cycle. Lower thermostat to lowest setting and verify boiler goes off.

Inspect System Piping

Verify all connections are watertight. Repair any leaks immediately.

Test Ignition System Safety Shutoff Device

1.Turn off manual gas valve

2.Set thermostat to call for heat

3.Boiler begins normal sequence of operation

4.After approximately 20 seconds (pre purge, state code 4) gas valve is powered (state code 6).

5.After 13 second trial for ignition, gas valve closes, (state code 10)as integrated boiler control senses that flame is not present.

6.After about 30 seconds, control will go back to step 4 and make two more attempts to light the burner, then go into soft lockout and display Error code 62.

7.To restart system, open manual gas valve that was closed in Step 1. Reset lockout by breaking and restoring power to boiler. Observe normal operation.

Test High Limit Control And Adjust

While burner is operating,adjust high limit setpoint below actual boiler water temperature. Burner should go off while circulator continues to operate. Raise limit setting above boiler water temperature and burner should reignite after inter-purge (retry delay). Set high limit control to design temperature requirements of system. Maximum high limit setting is 190°F. Minimum high limit setting is 80°F.

Measure Natural Gas Input Rate

Correct input rate is essential for proper and efficient operation of the burner and boiler.

1.Determine elevation at installation site.

2.Table 1 and Table 2, Page 6 to determine correct input rate for the local elevation.

3.Obtain yearly average heating value of local gas supply from gas utility. At sea level elevation, it should be approximately 1000 Btu’s per standard cubic foot.

4.Operate boiler for 5 minutes.

5.Turn off all other gas appliances, extinguishing standing pilots where applicable.

6.At gas meter, measure time in seconds required to use one cubic foot of gas.

7.Calculate input rate according to the following formula: 3600 x heating value from step 3

Btuh in put rate = time from step 6

8.Measured input rate should be within +/-2% of input rating from step 2. If within 2%, go to step 9. If not, adjustment is required, proceed as follows:

A.Turn boiler off

B.Set up U-tube manometer or differential pressure gauge for measuring manifold pressure. See Figure 27, Page 44.

C.Manometer or gauge must be able to read at least 0.0 to 3.0 inches water column of pressure, and resolve to at least 0.1 inches water column.

D.Turn boiler on.

E.Manifold pressure has been nominally set at 2.5 inches w.c. Manifold pressure and input rate must always be measured with pressure regulator cover screw installed. Cover screw must be removed for adjustment. Manifold pressure reading will change (increase) when cover screw is removed.

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