Pentair MT User Manual
Page 13
MegaTherm Commercial Pool Heating Boiler
Page 13
SECTION 5.
Troubleshooting and Analysis of
Service Problems
1.
For proper service and problem diagnosis of the
boiler and system, the following tools are
required:
a.
Gas pressure test kit with range from zero
to 14" W.C. Either a slack tub manometer
or an accurate gas pressure gauge is
acceptable with proper adaptors which will
connect to the available fittings in the line
and on the gas valve.
b.
Electric meter(s) with the following ranges:
0 to 500 volts A.C.
0 to 1000 ohms continuity.
c.
Millivolt meter with the following ranges:
0 to 50 millivolts. 0 to 500 millivolts.
0 to 1000 millivolts.
d.
Tube cleaning kit consisting of reamer,
stainless steel brush, speed handle and
handle extensions.
e.
Accurate thermometer and pressure gauge.
2.
In addition, the boiler should be equipped with a
thermometer with proper ranges.
Boiler Will Not Fire
Possible Cause
What To Do
Electric Power
is off.
Check to see that main power switch
is ON. Use testing device to trace
power to boiler junction box.
Operating or
safety control has
opened circuit to
electric gas valve.
Turn off power. Use continuity tester
to check continuity across terminals of
each operating and safety control
switch up to the electric gas valve.
Replace defective control.
Pilot flame is out.
Relight pilot per instructions.
Manual reset
device has
tripped.
Follow instructions for start-up. Reset
pilot safety and all manual reset
safety switches.
No gas pressure to
burners.
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.
Electric gas valve
operator is burned
out or shortened.
Disconnect wiring harness at gas
valve terminals. Check continuity to
actuator coil. If open circuit or short is
indicated, replace coil or operator.
Boiler is Pounding, Knocking,
or Emitting Steam from Relief Valves
Possible Cause
What To Do
Lower or no water
flow.
This condition is usually caused by
lack of adequate water flow through
heater. check the following:
1. Is the heater wired into the pump
circuit so that the heater 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 heater and
the system.
3. Examine pump for clogged
impeller.
4. Check water filter.
Debris from system
is blocking tubes.
Remove header covers. Examine all
tubes and waterways. Use new
gaskets when reassembling. Clean
out tubes.
Scale has formed
in tubes.
This is always caused by heavy
mineral content of the water or
clogged filter. Check the water
chemistry. Replace the filter and
clean all the internal wet surfaces.
Soot in Flueways or in Tubes, or Noxious
Fumes Indicative of Bad Combustion
Possible Cause
What To Do
Combustion air
supply to
equipment room is
inadequate.
Check air supply opening. Look for
debris in screen or louvre which
covers combustion air opening, or for
material blocking the opening.
Stack or vent is
blocked or
restrictive.
Look for blocked stack and excessive
number of elbows in stack or
excessive length of horizontal runs.
Severe down draft
is causing spillage
of flue products
into room.
Check for (1) proper vent cap on
stack; (2) adequate height of stack
above roof; (3) equipment exhausting
air from inside of building.
Gas pressure to
burners is
excessive.
Check gas pressure with
manometer,and adjust with heater
firing at full rate.
Heater not fitted
for the fuel being
supplied.
See nameplate for correct fuel.
Heater installed at
high altitude
without proper
derating.
Installations at altitudes in excess of
2000 ft. above sea level are subject
to jurisdiction of the local inspection
authorities. Check with the factory.
Water Dripping in Firebox
Possible Cause
What To Do
Tube in heat
exchanger has
overheated and
ruptured.
A tube failure is almost always
caused by:
(a) Scale formation in the tube, or:
(b) inadequate water flow through the
boiler.
Replace heat exchanger tube(s) and
check for proper flow.