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Mighty Therm Commercial Pool Heating Boiler
1. Symptom: heater is pounding, knocking or emitting steam from relief valve
Possible Cause
A.
Low or no water fl ow
(most likely).
B.
Debris from system piping
is blocking tubes.
C. Scale has formed in tubes
from high mineral content.
2. Symptom: heater will not fi re
A.
Heater not getting power.
B.
Operating or safety control has
opened circuit to electric gas valve.
C. Pilot fl ame is out.
D. Manual reset device has tripped.
E.
No gas pressure to burners.
F.
Electric gas valve operator is
burned out or shorted.
G. Pump does not run.
H. Pump runs, but fl ow switch
not closing.
I.
Field interlock open.
3. Symptom: pressure relief valve leaking intermittently or steadily
A.
Faulty relief valve.
4. Symptom: soot in fl ueways or in tubes, or noxious fumes from bad combustion
A.
Combustion air supply to heater
room is inadequate.
B.
Stack or vent is blocked or restrictive. B.
C. Severe downdraft is causing
spillage of fl ue products into room.
D. Gas pressure to burners is excessive. D. Check gas pressure with manometer, and adjust with heater fi ring at full rate.
E.
Heater not fi tted for the fuel supplied. E.
F.
Heater installed at high altitude
without proper derating.
5. Symptom: water dripping in fi rebox
A.
Tube in heat exchanger has
overheated and ruptured.
B.
Heater is condensing from low
inlet temperature.
What to Do
A.
Is the heater wired into the fi lter pump circuit so that the heater cannot fi re
unless the pump is running?
Check to see that all valves in system are open to be sure that water can
circulate through the heater.
Check pool fi lter, clean if clogged.
Examine heater pump for clogged or frozen impeller.
Check fl ow switch for proper operation and range setting.
B.
Remove header covers. Examine all tubes and waterways. Clean out tubes.
Use new gaskets when reassembling.
C. Clean tubes with tube cleaning kit. Determine hardness. Check water fl ow, and
clean pool fi lter.
A.
Check to see that power switch is "ON." Use testing device to trace power to
heater power source. Check fuse and secondary voltage in heater control.
B.
Turn off power. Check continuity across terminals of each operating and safety
control switch up to the electric gas valve. Replace defective control.
C. Relight pilot per instruction.
D. Reset pilot safety and all manual reset safety switches. Follow instructions for
start-up.
E.
Trace gas line to service shutoff cock. If service cock is open, trace gas line to
meter. If no pressure is present at meter, call for public utility service. If gas is
present in heater inlet, check pressures in following sequence: (1) downstream
from pressure regulator; (2) downstream from electric gas valve. Replace or
adjust as necessary.
F.
Disconnect wiring harness at gas valve terminals. Check continuity of actuator
coil. If open circuit or short is indicated, replace coil or operator.
G. Operate in manual. Check power to pump from relay, Check that pump/motor is
free to rotate. Replace relay or motor as necessary.
H. Check continuity across fl ow switch. Inspect paddle for proper movement.
Adjust fl ow range setting.
I.
Jumper terminals and isolate problem in other equipment.
A.
Replace with a new relief valve with proper setting (see rating plate).
A.
Check air supply opening. Look for debris in screen or louvre which covers
combustion air opening, or for objects blocking the opening.
Look for blocked stack and excessive number of elbows in stack or excessive
length of horizontal runs.
C. Check for (1) proper vent cap on stack; (2) adequate height of stack above
roof; (3) equipment exhausting air from inside of building; and (4) proper
installation of draft diverter.
See nameplate for correct fuel.
F.
Installations at altitudes in excess of 2000 ft. above sea level are subject to
jurisdiction of the local inspection authorities. Check orifi ce size, contact your
dealer or factory for proper size.
A.
Tube failure is almost always caused by scale formation in the tube, or
inadequate water fl ow through the heater.
B.
Check bypass valve adjustment.
Page 17
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