SECTI
ON
4
: M
AI
NT
E
NAN
C
E
38
H2O BOILER
HC SERIES IOM Manual
Unit out of adjustment
Insufficient draft
Check the gas manifold pressure to ensure it
complies with the value given in the factory test
report. If required, re-adjust the boiler/water (see
factory test report for the adjustment values).
Check the vent system to ensure it is not
clogged.
Unit fails at frequent
intervals
(excessive
cycling)
Operating temperature is set
too low.
Break in controls wiring.
Unit is over-sized
Check the setting on operating temperature
switch to ensure it is set at desire temperature.
If applicable, check the differential adjustment
on the operating temperature switch.
Check all connections to and from the wiring
block located immediately below the blower.
Check the maximum heat requirement with the
engineer and ensure the unit is of the appropriate
size.
Unclean combustion
Insufficient
air
in
the
mechanical room
Unit out of adjustment
Check all the louvers and air openings in the
mechanical room to ensure they are free of any
obstructions and there is sufficient inflow of
fresh air into the room.
Using a gas analyzer re-adjust the air and gas
settings.
Air bubble sound in
the unit.
Poor water circulation in one
or both coils
Foreign material in one or
both coils.
Steam pockets in one or both
coils.
Completely purge each coil.
Drain each coil with pressurized air and re-
purge.
Check water flow rate to ensure it complies with
the required minimum flow rate.
Gas Odor
Leak in piping.
Exhaust gas leakage
Using a gas detector, check all the connections
(inlet and outlet) of all instruments on the gas
line. Repair as required.
Check the vent system to ensure there are no
cracks or other openings (holes cut for insertion
of thermocouples during the start-up). Repair if
required.
D-VAC Sales Inc. Email: dmann@dvachvac.com Tel: (516) 256-3131 www.dvachvac.com
