maintained. To check setting, first, remove the belt guard and then, using fingers, compress the belt at a point midway between the sheaves. The proper setting at this point measured between the outer edges of the belt, should be between 1-3/4" and 1-7/8". If adjustment is necessary loosen the two mounting bolts, and move the fuel unit up or down to give the necessary belt setting. Then re-tighten the mounting bolts securely and replace the belt guard.

PERFORMANCE CHECK LIST

QUESTION: What Causes Unit To Soot Up?

Answers:

1. Nozzles
2. Flame Impingement
3. Firing Head
4. Leaks
5. Improper Burner Settings
6. Lack of Normal Maintenance
7. Poor Ignition
8. Retention Ring Cokes

Definitions of Answers:

1. Nozzles

A. Dirty
B. Wrong type of nozzle, or manufacturing defect

2. Flame Impingement

A. High CO₂
B. Diffuser and choke ring clearance not uniform
C. Dirty nozzle, or poor patterns
D. Leaks

3. Firing Head

A. Diffuser and choke ring clearance not uniform
B. Diffuser and choke ring face dimension out of tolerance.
(See A Dimension, Figure 1)
C. Dirty fuel systems

4. Leaks

A. Induced fan gasket, or burner gasket improperly sealed
B. Front cover assembly improperly installed or sealed

5. Improper Burner Settings

A. Unit not checked out completely by the serviceman
B. Flame pattern erratic (Not concentric). Burner set up by
CO₂ only (Burner should be set up by CO₂, smoke and
visual observation.)

6. Lack of Normal Maintenance

A. Self explanatory (Recognition of the advantages of
preventive maintenance).

7. Poor Ignition

A. No delay in oil valve, unit flutters on start up.
B. Electrodes out of position
C. Too much combustion air (Air shutter open too wide)

8. Retention Ring Cokes

A. Defective nozzle
B. Cone, choke and nozzle out of adjustment (See Figure 1)
C. Fluttering starts

DOMESTIC HOT WATER

In order to obtain the rated capacity of the instantaneous domestic hot water coil limit control should be set to maintain 200° F boiler water temperature.

Flow regulator and tempering valve should be installed on all instantaneous domestic hot water coil systems.

BURNER SETTING

The burner is adjusted at the factory before shipment but in case of improper operation at some future date Figure 1 will show proper setting. In all cases the flame retention ring should be concentric with the choke.