Chapter 6 Troubleshooting
6-4 750-177
Problem Solution
SHUTDOWN OCCURS
DURING FIRING cont’d
7. Improper air/fuel ratio (lean fire).
A. Slipping linkage.
B. Damper stuck open.
C. Fluctuating fuel supply.
1). Temporary obstruction in fuel line.
2). Temporary drop in gas pressure.
8. Interlock device inoperative or defective.
MODULATING MOTOR DOES
NOT OPERATE
1. Manual-automatic switch in wrong position.
2. Linkage loose or jammed.
3. Motor does not drive to open or close during pre-purge or close on burner
shutdown.
A. Motor defective.
B. Loose electrical connection.
C. Damper motor transformer defective.
4. Motor does not operate on demand.
A. Manual/automatic switch in wrong position.
B. Modulating control improperly set or inoperative.
C. Motor defective.
D.Loose electrical connection.
E. Damper motor transformer defective.
EXCESSIVE RUST ON TUBES 1. Condensation of the flue gases on cool tubes is causing rust.
A. Change system so return temperatures are above 120
°F or install blend
pump to assure water temperatures entering boiler are above 120
°F.
2. Open stack or condensate running down stack or breeching.
A. Stack should be offset. Insulate and drain stack.
3. Frequent cold starts.
A. Reset controls for less cycling.
To Next Page
Loading...
