TROUBLE SHOOTING
Use the Trouble Shooting Guide (pages 19 to 21) to assist in locating where a malfunction in the control system is occurring.
4PROCEDURE FOR MEASURING FAN DIFFERENTIAL PRESSURE (See Figure 13).
a.With boiler off, remove black silicone tubing from low side of pressure switch.
b.With tee and ¼” aluminum stubs, connect manometer as shown with additional tubing.
c.Start boiler and read differential pressure on manometer. Should be
d.Stop boiler, remove manometer and reconnect black silicone tubing to duct.
5CHECK GAS INPUT RATE TO BOILER
a.Input rate and maximum inlet pressure shown on rating label must not be exceeded. Inlet pressure must not be lower than minimum inlet pressure shown on rating label.
b.All rate checks and all adjustments are to be made while boiler is firing - all other appliances connected to the same meter as the boiler must be off.
c.Water manometer or water column gauge should be connected to a shutoff valve installed in the 1/8” pipe tapping in the gas valve - boiler off. By installing gas valve up stream of manometer, gas pressure can be introduced gradually - without shutoff valve, surge of pressure when boiler is turned on, could blow liquid out of manometer. Replace plug in gas valve when rate check is finished.
d.Approximate input - Adjust pressure regulator on combination gas control so that manifold pressure is equal to that shown on rating label. Determine what
flow (cu. ft.) should be in 3 minutes using formula below:
cu. ft. per | = | Btuh Input (from Rating Label) |
3 min. | = | 20000 |
Clock gas meter for three (3) minutes using second hand or stop watch.
For minor input changes readjust pressure regulator on combination gas control. Increase or decrease manifold pressure to obtain corresponding increase or decrease in gas input.
Turning regulator adjusting screw clockwise increases pressure. Counterclockwise rotation decreases pressure. If it is necessary to increase manifold pressure more than 0.3” of water to obtain rated input, remove orifices and drill one size larger. Reinstall and recheck input rate.
Figure 13
PROCEDURE FOR MEASURING FAN DIFFERENTIAL
PRESSURE
18