Purge Air From Water System; Check Thermostat Circuit(S); Condensate Removal - Westinghouse WBMC**500 Manual

Installation start-up maintenance parts warranty commercial gas-fired boilers
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1. Fill the system only after ensuring water chemistry meets the
requirements listed in this manual.
2. Close the manual and automatic air vents and boiler drain
valve.
3. Fill to the correct system pressure. Correct pressure will vary
with each application.
a. Typical cold water fill pressure for a residential system is 12
psi.
b. Pressure will rise when boiler is turned on and system water
temperature increases. Operating pressure must never exceed
the relief valve pressure setting.
4. At initial fill and during boiler startup and testing, check
system thoroughly for leaks. Repair all leaks before proceeding
further.
Eliminate all system leaks. Continual fresh make-up water will
reduce boiler life. Minerals can build up in the heat exchanger,
reducing heat transfer, overheating the heat exchanger and
causing heat exchanger failure.
5. The system may have residual substances that could affect
water chemistry. After the system has been filled and leak
tested, verify that water pH and chlorine concentrations are
acceptable by sample testing.
It is important to purge the system of air to avoid damage to
the boiler.
E. Purge Air from Water System
Purge air from the system:
a. Connect a hose to the purge valve and route hose to an area
where water can drain and be seen.
b. Close the boiler or system isolation valve between the purge
valve and fill connection to the system.
c. Close zone isolation valves.
d. Open quick-fill valve on cold water make-up line.
e. Open purge valve.
f. Open the isolation valves one zone at a time. Allow water to
run through the zone, pushing out the air. Run water until no
noticeable air flow is present. Close the zone isolation valves
and proceed with the next zone. Follow this procedure until all
zones are purged.
g. Close the quick-fill water valve and purge valve and remove
the hose. Open all isolation valves. Watch the system pressure
rise to correct cold-fill pressure. It is recommended that you
put the pumps into manual operation to assist in purging the
circuits.
h. Disconnect the wires that are connected to the THERMOSTAT
terminals of the customer connection board. Apply power to
the boiler. The display will show the temperature of the water
in the boiler. Press the v and ENTER keys simultaneously and
hold for 1 second. The display will read:
The central heating pump will come on. If you then press the
^ key, the central heating pump will shut off. The display will
read:
The DHW pump will come on. If the boiler is set up as a
cascade master and you then press the ^ key again, the
DHW pump will shut off. The display will read:
The system pump will come on. Use the ^ and v keys to toggle
between running each pump in the system as required to
help bleed out all entrapped air. Some good indicators that
air is removed include the absence of gurgling noises in the
pipes and pump operation becoming very quiet. Pressing ^
and v together at any time will return the boiler to normal
operation.
i. After the system has operated for five minutes, eliminate
any residual air by using the manual air vents located
throughout the system.
j. If purge valves are not installed in the system, open manual
air vents in the system one at a time, beginning with the
lowest floor. Close vent when water squirts out. Repeat with
remaining vents.
k. Refill to correct pressure.
F. Check Thermostat Circuit(s)
1. Disconnect the two external wires connected to the boiler
thermostat terminals (low voltage terminal strip).
2. Connect a voltmeter across these two incoming wires
with power supplied to the thermostat circuits. Close each
thermostat, zone valve and relay in the external circuit one at
a time and check the voltmeter reading across the incoming
wires.
3. There should NEVER be a voltage reading.
4. If a voltage reading does occur under any condition, check
and correct the external wiring. (This is a common problem
when using 3-wire zone valves.)
5. Once the external thermostat circuit wiring is checked and
corrected if necessary, reconnect the external thermostat
circuit wires to the boiler low voltage terminal strip. Allow the
boiler to cycle.
G. Condensate Removal
1. The boiler is a high efficiency condensing boiler. Therefore,
the unit has a condensate drain. Condensate fluid is nothing
more than water vapor, derived from combustion products,
similar to that produced by an automobile when it is initially
started.
Condensation is slightly acidic (typically with a pH of 3 to 5)
and must be piped with the correct materials. Never pipe the
condensate using steel, copper, brass or other materials that
will be subject to corrosion. Plastic PVC or CPVC pipe are the
only approved materials.
A condensate neutralizer, if required by local authorities,
can be made up of lime crystals, marble or phosphate chips
that will neutralize the condensate. This may be done by the
installer or you may purchase a condensate neutralizer from
Westinghouse (7350P-611).
2. The boiler is equipped with a ¾ female socket weld fitting
connection that must be piped to a local drain. It is very
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WHL-033 Rev. 1.29.16

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