Smith boiler troubleshooting

The following troubleshooting table contains a list of the most common gas boiler issues and their solutions. By the signs described in the table, you can trace the cause. Solutions are described in the opposite column. Most problems can be solved without calling a technician.

Smith 88 boiler troubleshooting

ProblemPossible CauseSuggested Remedy
Pilot OutageDefective ThermocoupleReplace
Heavy Draft Blowing across PilotRedirect Air Movement or Eliminate
Plugged Pilot OrificeReplace Orifice
No GasCheck Manual Pilot Valve Check Main Gas Shut-Off Valve Check Manual Meter Valve Consult Gas Company
Defective Thermopilot SwitchReplace
Defective Ignition Control
Main Gas Valve Will Not Open (Spark Ignited Pilot)No PowerCheck Power Source with Meter Check Fuses
Defective Gas ValveReplace
Low Water Level in Boiler or System Causing Low Water Cut-off to FunctionCheck for Leaks Check Feeder (if Supplied)
Defective Ignition ControlReplace
High Gas Pressure Switch Open (if Provided)Check Switch Setting Check Manifold Gas Pressure
Low Gas Pressure Switch Open (if Provided)
Main Gas Valve Will Not Open (Standing Pilot)No PowerCheck Power Source with Meter Check Fuses
Defective Gas ValveReplace
Pilot OutRelight Pilot (May have defective pilot valve or relay)
Low Water in Boiler or System Causing Low Water Cut-off to FunctionCheck for Leaks Check Feeder (if Supplied)
Defective Thermopilot SwitchReplace
Defective Thermocouple
High Gas Pressure Switch Open (if Provided)Check Switch Setting
Check Manifold Gas Pressure
Low Gas Pressure Switch Open (if Provided)Check Switch Setting
Check Inlet Gas Pressure
Burner(s) Burning with Yellow FlameAir Adjustment Screws Turned in Too FarAdjust Screws Out
Low Gas Pressure in Manifold (Insufficient Air Injection)Adjust Main Gas Pressure Regulator or Check Line Pressure
Burner Ports Partially Closed (Rust, Dirt, Lint, etc)Replace Burners or Clean Ports
Insufficient Air for CombustionCheck Size of Combustion Air Openings to Room If Undersized, Correct as Required Check for Negative Pressure in Boiler Room
Oversized Burner OrificeInstall Correct Orifice
High Gas Pressure in ManifoldAdjust Main Gas Pressure Regulator
Gas Spillage from Draft Hood Relief OpeningInsufficient Draft - Chimney Too LowIncrease Height or Add Induced Draft Fan
Insufficient Draft - Chimney Too SmallReplace Chimney or Add Induced Draft Fan
Insufficient Draft - Blockage in Chimney or VentRepair Chimney or Vent
Insufficient Draft - Downdraft Caused by Chimney Location with Respect to Other Buildings, Roofs, etc.Install Chimney Cap
Negative Pressure in Boiler Room (Due to Exhaust Fan or Duct System)Remove Exhaust Fan or Isolate Fan From Boiler Room
Insufficient Combustion Air OpeningsProvide Correctly Sized Combustion and Ventilation Air Openings
Main Gas Valve Opens But No Gas FlowsManual Valve Closed at Gas TrainOpen Valve
Manual Valve Closed at Meter
Test Firing Valve Closed (if Provided)
Water Hammer On Start-UpSags in Steam Piping or not enough PitchCorrect Piping Condition
Concentric reducers causing condensate poolingCorrect Piping
Drip trap failed closedReplace Trap or Trap Element
Dry returns wetted due to new boiler water line higher than old boilerCorrect Piping or Install Feed System and Traps
No drip line on the back side of a back-pitched motorized valveInstall Drip Line and Trap
Water Hammer During Mid-CycleClogged returns on gravity systemClean or Re-Pipe Return Line(s)
Incorrect near-boiler piping causing wet steam to systemCorrect Piping per Manual
Trap failed open, allowing steam to enter returnsReplace Trap or Trap Element
{Radiator Hammer} Large radiator may be vented too quicklyUse smaller Air Vent or Use Two Small Vents in Place of One Large Vent, One Mounted Higher than the Other
Long nipple at Hartford LoopReplace with Close Nipple
Water leg or back slope in return line to receiver tank, causing water pocketingCorrect Piping
Trap installed at receiver tank, causing water trapping in returnRemove Trap at Tank, Install Drip Traps and Radiator Traps where Required
Boiler feed pump or condensate pump feed rate too fast, causing spraying into equalizerThrottle Flow Rate
No drip on the inlet side of a forward pitched motorized valveAdd Drip Line and Trap
Uninsulated steam piping, causing excessive condensate loadsInsulate Steam Pipes
Water Hammer on Shut-DownClose nipple on Hartford Loop too highRepipe 2" to 4“ (5cm to 10cm) Below Water Line
Uninsulated steam piping in boiler room, but system piping insulated, causing vacuum condition on shut-downInsulate Steam Pipes
Hammering in the BoilerPoor circulation in the boiler due to sludge accumulationClean and Blowdown the Boiler
No Heat or Poor Heat Distribution in the BuildingMain vents not workingReplace Main Vents, Repiping away from End of Lines if Needed
Drip Traps failed closedReplace Traps or Trap Elements
Radiator traps failed open, allowing pressurization of the returns
Water legs or back slope in return lines to receiver tank, preventing air from venting out receiver ventCorrect Piping
Boiler pressure too high, causing air vents to lock up or blowing water loop sealsReduce Operating Pressure
System or Boiler Overfilling or FloodingNew boiler water content smaller than old boilerInstall Boiler Feed System with Receiver Tank Large enough for Condensate
Boiler water feed rate or pump rate too fast causing water level to collapse (due to collapse of steam bubbles in boiler water)Reduce Feed Rate
Foaming, priming or surging due to poor water qualityClean the Boiler
Excessive Water Level BouncePoor water quality, causing foaming and surging
Incorrect near-boiler piping, such as undersized or incorrectly placed risersPipe per Manual
Boiler water feed rate or pump rate too fastReduce Feed Rate
Rapid CyclingAir vents or traps not venting air, preventing steam from getting to radiation and pressurizing the air pocketReplace Vents or Traps
Pressure differential on pressure control too closeAdjust Control Differential
Nuisance outages of water level control due to boiler water level bounceSee Excessive Water Level Bounce Above

Smith GB100 boiler troubleshooting

PROBLEMPOSSIBLE CAUSESCORRECTIVE ACTIONS
Burners not functioning.1. No power.1. Check line voltage wiring and fuses.
2. Limit not working.2. Check wiring and contacts, relay, temperature setting. Clean and adjust as necessary.
3. Flame rollout switch open.3. Replace switch. Locate cause and correct.
4. Blocked vent switch open.4. Reset blocked vent switch. Locate cause and correct.
5. Gas off at boiler gas valve.5. Start boiler using Lighting/Operating Instructions.
6. Gas off external to boiler.6. Check any gas valves in the line.
7. Plugged orifice spuds.7. Check, clean and re-install.
8. Defective gas valve.8. Use Figure 8.1 to troubleshoot intermittent ignition gas valve. Replace if necessary.
9. Improper wiring.9. Check and correct.
10. Vent damper malfunctioning.10. Refer to vent damper manufacturer’s instructions. Replace if necessary.
Burners will not shut down.1. Defective gas valve.Troubleshoot intermittent ignition gas valve. Replace if necessary.
2. Short circuit.2. Check and correct wiring.
Flashback or burning at orifice spuds.1. Manifold gas pressure too low.1. Adjust to proper pressure.
2. Improperly sized/drilled orifice spuds.2. Install correct spuds.
3. Leaking gas valve.3. Replace valve.
4. Burrs on orifice.4. Remove burrs.
5. Low supply gas pressure.5. Contact gas supplier if natural gas. Adjust regulator if LP gas.
6. Excessive downdraft or draft problems in boiler room.6. Check air supply, ventilation and venting system.
Delayed ignition.1. Insufficient pilot flame.1. Increase pilot gas flow.
2. Pilot bumer/orifice clogged.2. Clean pilot burner and orifice.
3. Overfiring.3. Reduce rate to input on rating label.
4. Misaligned burners or pilot.4. Realign burners or pilot.
5. Draft problem in boiler room.5. Check air supply, ventilation and venting system.
Excessive condensation in vent.1. Underfiring.1. Increase rate to input on rating label.
2. Limit (Aquastat) set too low.2. Reset Aquastat to higher setting.
3. Vent pipe too long.3. Reposition boiler to reduce length.
4. Inadequate chimney or venting system.4. Check chimney and venting recommendations.
Boiler not heating properly.1. Underfiring.1. Increase rate to input on rating label.
2. Limit set too low.2. Reset Aquastat to higher setting.
3. Air in system.3. Vent air from all points in system.
4. Circulator malfunctioning.4. Check circulator, replace if necessary.
5. Circulation system clogged.5. Shut down and cool boiler, drain and flush system.
6. Incorrect thermostat heat anticipator setting.6. Adjust heat anticipator.
Fumes or gas odors1. Leaks in gas piping or fittings.1. Locate and repair or replace.
2. Leaks in gas service line or meter.2. Shut down boiler and notify gas provider.
3. Obstructed chimney.3. Check, repair and/or clean chimney.
4. Obstructed flueways or vent.4. Clean flueways or vent and remove obstructions.
5. Undersized chimney or vent, high draft loss in vent.5. Check National Fuel Gas Code and vent manufacturer s recommendations.
6. Draft problem in boiler room.6. Check air supply, ventilation and venting system.
7. Overfiring.7. Reduce rate to input on rating label.
8. Vent damper malfunctioning.8. Refer to vent damper manufacturer’s instructions. Replace if necessary.