LAARS Mighty Therm PH (Sizes 500-1825) - Installation, Operation and Maintenance Instructions - Manual (Page 17)

Mighty Therm Hydronic Boiler Page 17
5. BOILER IS POUNDING, KNOCKING OR EMITTING
STEAM FROM RELIEF VALVES.
Possible Cause What To Do
A. Low or no water flow. A. This condition is usually
caused by lack of adequate
flow through boiler.
Check the following:
(1) Is the boiler wired into
the pump circuit so that the
boiler cannot fire unless
the pump is running?
(2) Check to see that all
valves in system are open
to be sure that water can
circulate through the boiler
and the system.
(3) If the system has
automatic water valves (2-
way or 3-way) that can cut
off the water flow through
the boiler check to see
that they are equipped with
end-switches which shut
the boiler down when the
water flow through the
boiler is reduced by 70%
from full flow.
(4) Examine pump for
clogged impeller.
B. Low or no system pressure. B. Clean strainer in pressure
reducing valve. Look for
closed valve water line or
a leak in the system.
C. Clogged "Y" strainer. C. Remove strainer element
and clean screen.
D. Debris from system piping is D. Remove header covers.
blocking tubes. Examine all tubes and
waterways. Use new
gaskets when reassembling.
Clean out tubes.
E. Scale has formed in tubes. E. This is always caused by
the inflow of raw water into
the system. Clean tubes
with tube cleaning kit.
Determine hardness.
Check for modified flow if
necessary.
7. WATER DRIPPING IN FIREBOX.
Possible Cause What To Do
6. SOOT IN FLUEWAYS OR IN TUBES,
OR NOXIOUS FUMES INDICATIVE
OF BAD COMBUSTION.
Possible Cause What To Do
A. Combustion air supply to A. Check air supply opening.
boiler room is inadequate. Look for debris in screen or
louvre which covers
combustion air opening, or
for material blocking the
opening.
B. Stack or vent is blocked or B. Look for blocked stack and
restrictive. excessive number of elbows in
stack or excessive length of
horizontal runs.
C. Severe down draft is causing C. Check for (1) proper vent cap on
spillage of flue products into stack; (2) adequate height of
room. stack above roof; (3) equipment
exhausting air from inside of
building; and (4) proper
installation of draft diverter.
D. Gas pressure to burners is D. Check gas presssure with
excessive. Manometer, and adjust
with heater firing at full rate.
E. Boiler not fitted for the fuel E. See nameplate for correct
being supplied. fuel.
F. Boiler installed at high F. Installations at altitudes in
altitude without proper excess of 2000 ft. above
derating. sea level are subject to
jurisdiction of the local
inspection authorities.
Tub in heat exchanger has A tube failure is almost always
overheated and ruptured. caused by (1) scale formation in the
tube or (2) inadequate water flow
through the boiler.