American Standard PFWF071A93ABA Installation Manual page 61

Control and Safety Switch Adjustment
Limit Switch Check Out
The limit switch is a safety device designed to shut
off the burner should the boiler become overheated.
Since proper operation of this switch is important
to the safety of the unit, it must be checked out on
initial start up by the installer.
IMPORTANT: To check for proper operation of the
Water Temperature Limit switch (WTL), shut off the
power to the boiler and TEMPORARILY bypass the
supply water thermostat (SWT) with a TEMPORARY
JUMPER. TEMPORARILY remove power from the
boiler water circulator pump and restore power to the
boiler. Burners should come on and operate. Closely
monitor the water temperature. DO NOT allow the
boiler to overheat excessively during the checkout of
the WTL limit switch. When the boiler water tem-
perature reaches 230°F, the burners should turn off
automatically. Immediately shut off power to the
boiler if the burners did not shut off automatically
as the water temperature reached 230°F. The WTL
limit switch must be replaced and proper operation of
the new WTL verifi ed.
After the boiler cools, REMOVE THE JUMPER from
the SWT and RESTORE POWER to the boiler and
the boiler water circulator pump.
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WARNING
!
CARBON MONOXIDE POISONING HAZARD
Failure to follow the steps outlined below for each
appliance connected to the venting system being
placed into operation could result in carbon monoxide
poisoning or death.
The following steps shall be followed for each appliance
connected to the venting system being placed into
operation, while all other appliances connected to the
venting system are not in operation:
1. Seal any unused openings in the venting system.
2. Inspect the venting system for proper size and
horizontal pitch, as required in the National Fuel Gas
Code, ANSI Z223.1/NFPA 54 or the CAN/CGA B149
Installation Codes and these instructions. Determine
that there is no blockage or restriction, leakage,
corrosion and other deficiencies which could cause an
unsafe condition.
3. As far as practical, close all building doors and
windows and all doors between the space in which the
appliance(s) connected to the venting system are
located and other spaces of the building.
4. Close fireplace dampers.
5. Turn on clothes dryers and any appliance not
connected to the venting system. Turn on any exhaust
fans, such as range hoods and bathroom exhausts, so
they are operating at maximum speed. Do not operate
a summer exhaust fan.
6. Follow the lighting instructions. Place the appliance
being inspected into operation. Adjust the thermostat
so appliance is operating continuously.
7. If improper venting is observed during any of the above
tests, the venting system must be corrected in
accordance with the National Fuel Gas Code,
ANSI Z221.1/NFPA 54 and/or CAN/CGA B149
Installation Codes.
8. After it has been determined that each appliance
connected to the venting system properly vents where
tested as outlined above, return doors, windows,
exhaust fans, fireplace dampers and any other gas-fired
burning appliance to their previous conditions of use.
18-CG03D1-4
61