WOOD BOILER INSTRUCTIONS Page 60 Copyright © 2011 Seton Wood Boilers all rights reserved
BOILER MAINTENANCE
Cir
culating Pump: Some of the older style boiler pumps require lubrication for the motor and the pump. The motor
normally requires a few drops and the pump bearing should have and oil port. This needs to be filled to keep the oil
wicks wet. Refer to the manufacturer instructions for lubrication procedure for you pump. There maybe more than one
pump on you system. Some of the smaller cartridge style pumps do not require any maintenance. The volume of water
circulated by the pump is very important to the boiler operation. Too little water will boil inside the heating coil and
plug it with scale. This will sound like a crackling sound inside the boiler when the burner is operating. A single pres-
sure gauge piped across the pump inlet and outlet is the best way to monitor pump performance. As the pressure dif-
ference increases across the pump the lower the volume. The lower the pressure differences the higher the volume.
Another way to check water flow is by temperature. When the burner is operating check the temperature rise through
the boiler. Most are designed for a 10%F TD with nominal water flow. If the TD is higher 25%F or more the water
flow is too low and can start to boil off in the heating coil.
Temperature Setpoint: There could be up 4 temperature controller on a hot water boiler system. Room Thermostat,
Boiler Water Temperature Control, Circulation pump temperature control, and the safety high limit control.
Operating set point is normally an external control to the boiler. It controls the temperature of the circulating water.
This can be a fixed setpoint set around 160°F to 180°F. Outdoor reset controls are not recommended.
Circulation thermostats are used to start and stop the circulation pump and can be combined in the same control as
the high limit. Normally the circ pump should be set around 100°F. On atmospheric boiler with draft hoods after the
burner shuts down the continued draft starts to cool the water .Air from inside the boiler room is cooler then the water
temperature in the boiler system. By shutting down the boiler circuit pump after the water cools helps to reduce this
heat loss.
High limit control is a safety limit switch that will shut the burner off if the water temperature gets too high. Check
with the boiler manufacturer for the proper set point for your system. These are normally around 200°F but can be
higher or lower. I have often found these being used as the operating control for the boiler because they are shipped
with the boiler and the installer does not add the external operating control leaving the boiler without a safety high
limit
control.
Coil Cleaning: Atmospheric boilers are used extensively in residential and small commercial applications for space
heating, potable hot water and for pool and spas. The coils on these units plug up externally from the flue gas passing
between the tubes. This reduces heat transfer and causes flue gas to spill out the front of the boiler. Every few years
the top needs to be removed and the coil needs to be cleaned. If you notice staining on the face of the boiler or can feel
hot flue gas spilling out the front of the boiler then the tubes is likely starting to plug up.