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Troubleshooting — general, Cgi-4e gas-fired water boiler — boiler manual, Air pressure switch – Weil-McLain GOLD CGI-4E User Manual

Page 48: Before troubleshooting, Check the following

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GOLD

CGi-4E Gas-Fired Water Boiler — Boiler Manual

48

Part Number 550-110-711/1108

Troubleshooting — general

11a

Air pressure switch

Make sure boiler water temperature is

100 °F or cooler before starting proce-

dure to obtain appropriate readings.

The boiler will not operate correctly un-

less pressure switch hoses are correctly

located. The red hose connects from

the right side (negative) hose barb to

the flue collector. The white hose con-

nects from the left side (positive) hose

barb of the switch to the connector box

(between flue collector and inducer) as

shown in

Figure 36

, page 49.

Check pressure switch setting

1. See

Figure 36

,

page 49, and

Table 9

.

2. Remove both air pressure switch hoses from air pressure

switch.

3. Install tees and tubing as shown in

Figure 36

, page 49, to

inclined manometer.

4. Turn off gas valve and set thermostat to call for heat. Inducer

will run but burners will not ignite.

5. Check for 24 VAC between both air pressure switch termi-

nals.

Troubleshooting air pressure reading

1. If manometer reading is lower than the setpoint of the switch

(see

Table 9

) — check for possible causes:

• blockage in hoses
• obstruction in inducer housing outlet
• loose inducer wheel on motor shaft
• inducer motor not in proper rpm
• inducer back plate not sealed properly
• blockage in block assembly
• blockage in flue pipe or termination
• incorrect pressure switch

6. If manometer reading is above the setpoint of the switch (see

Table 9

), but there is not 24 VAC between both air pressure

switch terminals — replace air pressure switch.

Return to normal operation

When pressure reading is correct and air pressure switch is oper-

ating properly — remove tees and reinstall hoses to air pressure

switch.

Table 9

Pressure switch setpoint (for elevations

above 2,000 ft, contact your local Weil-

McLain sales office for details.)

Boiler model number

Inches W.C.

CGi-4E

1.36

Label all wires prior to disconnection when

servicing controls. Wiring errors can cause

improper and dangerous operation.

Never jumper (bypass) rollout thermal fuse ele-

ment or any other device except for momentary

testing as outlined in

Troubleshooting Charts

.

Severe personal injury, death or substantial

property damage can result.

Before troubleshooting:

1. Have the following items:

a. Voltmeter that can check 120 VAC and 24 VAC.

b. Microammeter with a minimum scale range of 0-25.

c. Continuity checker.

d. U-tube manometer.

2. Check for 120 VAC (minimum 102 VAC to maximum 132 VAC) to

boiler.

3. Make sure thermostat is calling for heat and contacts (including appro-

priate zone controls) are closed. Check for 24 VAC between thermostat

wire nuts and ground.

Check the following:

1. Wire connectors to control module are securely plugged in at module

and originating control.

2. Air pressure switch hoses are properly and securely plugged in and are

not damaged.

3. Verify gas supply pressure:

a. With boiler OFF — 13” w.c. maximum natural or propane gas

pressure upstream of gas valve.

b. With boiler ON — Upstream: 5” w.c. minimum natural gas pres-

sure or 11” w.c. propane gas pressure upstream of gas valve.

4. Verify gas manifold pressure (downstream of gas valve):

a. Natural gas:

Manifold pressure, high fire: 3.50” w.c.

Manifold pressure, low fire: 0.90” w.c. while in low fire at start-up

(60 seconds)

b. Propane gas:

Manifold pressure, high fire: 10.0” w.c.

Manifold pressure, low fire: 3.50” w.c. while in low fire at start-up

(60 seconds)

c. If necessary, adjust gas pressure on the gas valve as shown below.

After adjustments, refer to page 35 to check the flame.

High-fire gas pressure adjustment

Low-fire gas pressure adjustment

Honeywell VR8204Q two-stage gas valve