Smith 88 Installation And Operation Instructions Manual page 26

Problem
Water Hammer During Mid-Cycle
Water Hammer on Shut-Down
Hammering in the Boiler
No Heat or Poor Heat
Distribution in the Building
System or Boiler Overfilling or Flooding
Excessive Water Level Bounce
Rapid Cycling
26
INSTALLATION AND OPERATING INSTRUCTIONS
Possible Cause
Clogged returns on gravity system
Incorrect near-boiler piping causing wet steam
to system
Trap failed open, allowing steam to enter returns
{Radiator Hammer} Large radiator may be
vented too quickly
Long nipple at Hartford Loop
Water leg or back slope in return line to receiver
tank, causing water pocketing
Trap installed at receiver tank, causing water
trapping in return
Boiler feed pump or condensate pump feed rate
too fast, causing spraying into equalizer
No drip on the inlet side of a forward pitched
motorized valve
Uninsulated steam piping, causing excessive
condensate loads
Close nipple on Hartford Loop too high
Uninsulated steam piping in boiler room, but
system piping insulated, causing vacuum
condition on shut-down
Poor circulation in the boiler due to sludge
accumulation
Main vents not working
Drip Traps failed closed
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 vent
Boiler pressure too high, causing air vents to lock
up or blowing water loop seals
New boiler water content smaller than old boiler
Boiler water feed rate or pump rate too fast
causing water level to collapse (due to collapse of
steam bubbles in boiler water)
Foaming, priming or surging due to poor
water quality
Poor water quality, causing foaming and surging
Incorrect near-boiler piping, such as undersized
or incorrectly placed risers
Boiler water feed rate or pump rate too fast
Air vents or traps not venting air, preventing
steam from getting to radiation and pressurizing
the air pocket
Pressure differential on pressure control too close
Nuisance outages of water level control due to
boiler water level bounce
Suggested Remedy
Clean or Re-Pipe Return Line(s)
Correct Piping per Manual
Replace Trap or Trap Element
Use smaller Air Vent or Use Two Small Vents in
Place of One Large Vent, One Mounted Higher
than the Other
Replace with Close Nipple
Correct Piping
Remove Trap at Tank, Install Drip Traps and
Radiator Traps where Required
Throttle Flow Rate
Add Drip Line and Trap
Insulate Steam Pipes
Repipe 2" to 4" (5cm to 10cm) Below Water Line
Insulate Steam Pipes
Clean and Blowdown the Boiler
Replace Main Vents, Repiping away from End
of Lines if Needed
Replace Traps or Trap Elements
Replace Traps or Trap Elements
Correct Piping
Reduce Operating Pressure
Install Boiler Feed System with Receiver Tank
Large enough for Condensate
Reduce Feed Rate
Clean the Boiler
Clean the Boiler
Pipe per Manual
Reduce Feed Rate
Replace Vents or Traps
Adjust Control Differential
See Excessive Water Level Bounce Above