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TROUBLESHOOTING – SERVICE TIPS
Problem Possible Cause Suggested Remedy
Main Gas Valve Opens
Manual Valve Closed at Gas Train Open Valve
But No Gas Flows Manual Valve Closed at Meter Open Valve
Test Firing Valve Closed (if Provided) Open Valve
Sags in Steam Piping or not enough Pitch Correct Piping Condition
Concentric reducers causing condensate pooling Correct Piping
Drip trap failed closed Replace Trap or Trap Element
Water Hammer On Start-Up Dry returns wetted due to new boiler water line Correct Piping or Install Feed System and Traps
higher than old boiler
No drip line on the back side of a back-pitched Install Drip Line and Trap
motorized valve
Clogged returns on gravity system Clean or Re-Pipe Return Line(s)
Incorrect near-boiler piping causing wet steam Correct Piping per Manual
to system
Trap failed open, allowing steam to enter returns Replace Trap or Trap Element
{Radiator Hammer} Large radiator may be Use smaller Air Vent or Use Two Small Vents in
vented too quickly Place of One Large Vent, One Mounted Higher
than the Other
Long nipple at Hartford Loop Replace with Close Nipple
Water Hammer During Mid-Cycle Water leg or back slope in return line to receiver Correct Piping
tank, causing water pocketing
Trap installed at receiver tank, causing water Remove Trap at Tank, Installing Drip Traps and
trapping in return Radiator Traps where Required
Boiler feed pump or condensate pump feed rate Throttle Flow Rate
too fast, causing spraying into equalizer
No drip on the inlet side of a forward pitched Add Drip Line and Trap
motorized valve
Uninsulated steam piping, causing excessive Insulate Steam Pipes
condensate loads
Close nipple on Hartford too high Repipe 2" to 4" (5cm to 10cm) Below Water Line
Water Hammer on Shut-Down Uninsulated steam piping in boiler room, but
system piping insulated, causing vacuum Insulate Steam Pipes
condition on shut-down
Hammering in the Boiler Poor circulation in the boiler due to sludge Clean and Blowdown the Boiler
accumulation
Main vents not working Replace Main Vents, Repiping away from End
of Lines if Needed
Drip Traps failed closed Replace Traps or Trap Elements
No Heat or Poor Heat Distribution Radiator traps failed open, allowing pressurization Replace Traps or Trap Elements
of the returns
in the Building Water legs or back slope in return lines to receiver Correct Piping
tank, preventing air from venting out receiver vent
Boiler pressure too high, causing air vents to lock Reduce Operating Pressure
up or blowing water loop seals
New boiler water content smaller than old boiler Install Boiler Feed System withReceiver Tank
Large enough for Condensate
Boiler water feed rate or pump rate too fast
System or Boiler Overfilling or Flooding causing water level to collapse (due to collapse of Reduce Feed Rate
steam bubbles in boiler water)
Foaming, priming or surging due to poor Clean the Boiler
water quality
Poor water quality, causing foaming and surging Clean the Boiler
Excessive Water Level Bounce Incorrect near-boiler piping, such as undersized Pipe per Manual
or incorrectly placed risers
Boiler water feed rate or pump rate too fast Reduce Feed Rate
Air vents or traps not venting air, preventing
steam from getting to radiation and pressurizing Replace Vents or Traps
Rapid Cycling the air pocket
Pressure differential on pressure control too close Adjust Control Differential
Nuisance outages of water level control due to See Excessive Water Level Bounce Above
boiler water level bounce