How To Change Orifices; Heating System Problems & Causes - Smith Cast Iron Boilers GB250 SERIES Installation & Operation Manual

7. Continue this process for a minimum of one hour.
The process should continue until the steam is dry (no
water coming from the vent when the water in the gauge
glass is at a normal level, approximately 2/3 full). The
time required could vary up to 3 hours.
8. Turn burner to off position. While boiler is still hot,
drain completely through boiler drain. Make sure that all
low points in the return line are also completely drained.
These areas could trap chemicals and dirt.
9. Close boiler drain and refill with clean untreated warm
water. If warm water is not used, fill very slowly so as
not to crack boiler sections. Fill until water overflows
through vent pipe and runs clear.
10. Completely drain boiler again.Refill with clean
untreated water to normal level.
11. Remove vent drain piping and reinstall pressure
relief valve. Open gate valves on supply and return
lines. Turn on burner. System is now ready to operate.

HOW TO CHANGE ORIFICES

1. Shut off power supply and gas supply to the boiler.
2. Remove burner access panel. Lift burners up and to
rear until burners are disengaged from orifices.
3. Check orifices for proper drill size. Size is stamped
onto the body of the brass orifice (see Figure 4.1). Size
can also be checked by using a pin gauge.
4. All orifices are screwed into the manifold and may be
removed by using a 5/8" wrench or socket.
5. Reverse procedures above to install orifices and
burners. BE SURE TO REINSTALL BURNERS WITH
BURNER PORTS ON TOP SURFACE (UPRIGHT).
FIGURE 4.1
Boiler
Model
(1) Nat. Gas
Drill Size
(2) Prop. Gas
Drill Size
CAUTION: Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper
and dangerous operation.
Verify proper operation after servicing.
GB250-5L GB250-5H GB250-6
34 32
52 50
HEATING SYSTEM PROBLEMS & CAUSES
No Heat
1. Blown fuse or circuit breaker.
2. Switch turned off.
3. Pilot outage
4. IID system malfunction.
5. Flue damper not open.
6. Water level too low.
Insufficient Heat
1. Incorrect thermostat anticipator setting.
2. Low pressuretrol setting.
3. Boiler undersized or underfired.
4. Insufficient radiation.
Odor, Excessive Moisture In Building
1. Leak in piping.
2. Carbon build-up in flueways.
3. Blocked chimney.
Yellow Flame, Carbon Build-Up
1. Unit overfired.
2. Air shutter misadjustment.
3. Wrong orifices.
4. Burning in burner mixing tube.
Noise
1. Ignition or ignition noise due to incorrect air shutter
adjustment.
2. Whistle due to burr on orifices.
3. Burner "fluting" due to air shutter opening too wide.
Overheating
1. Wrong thermostat anticipator setting.
2. Bad thermostat location.
3. Bad thermostat.
GB250-7 GB250-8
31 33
50 51
20
GB250-9
32 32
51 50