Instruction manual

57
XI. MAINTENANCE AND SERVICE INSTRUCTIONS
A. MAINTENANCE OF LOW WATER CUT-OFF
DEVICES (when installed)
See Instructions provided with Low Water Cut-off Option
Card for Installation Instructions.
WARNING
Probe type low water cut-off devices require
annual inspection and maintenance.
1. PROBE TYPE LOW WATER CUT-OFF
Although these devices are solid state in their operation,
the probe is exposed to possible contamination in the
boiler water and subject to fouling.
Sometimes the LWCO can be found in the primary loop
of the boiler system. Ideally, shut off valves have been
installed between the loop containing the LWCO and
the rest of the system, to minimize the amount of system
draining.
It is important to physically remove the probe from
the LWCO tapping annually and inspect that probe for
accumulation of scale or sediment.
Follow these steps to inspect, clean and/or replace the
probe:
a. Turn off electric service to the boiler.
b. Drain boiler water to a level below the tapping for the
probe.
c. Disconnect wiring connections between the low water
cut-off control and the probe.
d. Remove the low water cut-off control from the probe.
DANGER
Assure that the boiler is at zero pressure before
removing the LWCO probe. Do not rely on the
pressure gauge to indicate that the boiler is at
zero pressure. Open the safety valve to relieve
all internal pressure prior to proceeding. Safety
valve discharge piping must be piped such that the
potential for burns is eliminated.
e. Unscrew the probe from the LWCO tapping.
f. Inspect that portion of the probe that is exposed to the
water for a scale or sediment buildup.
g. Light deposits may be removed by wiping the probe
with a damp cloth. Wiping the probe with a cloth
soaked in vinegar will remove more tenacious lime
deposits. The most stubborn deposits may be removed
from the probe by using a diluted amount, 3 parts of
water to 1 part of phosphoric acid (H
2
PO
4
).
CAUTION
Exercise caution when handling phosphoric acid
and follow the instruction label on its container.
h. Clean the pipe threads of the probe to remove old,
hardened pipe dope and other foreign matter.
i. Apply a moderate amount of good quality pipe dope
to the pipe threads on the probe, leaving the two end
threads bare. Do not use PTFE (Teon) tape.
j. Screw the probe into the LWCO tapping.
k. Mount the low water cut-off control on the probe.
l. Reconnect the control to probe wiring.
m. Fill the system with water.
n. Add boiler water treatment compound as needed (refer
to Paragraph B.).
o. Restore electric service to the boiler.
p. Fire burner to bring the water in the boiler to a boil
to drive off free oxygen.
q. WARNING — BEFORE RETURNING BOILER TO
SERVICE: Follow the low water cut-off instructions
provided with Low Water Cut-off Option Card.
B. BOILER AND SYSTEM CLEANING INSTRUCTIONS
FOR TROUBLE FREE OPERATION
1. Filling of Boiler and System — General —-In a hot water
heating system, the boiler and entire system (other than
the expansion tank) must be full of water for satisfactory
operation. Water should be added to the system until the
boiler pressure gauge registers 12 psi. To insure that the
system is full, water should come out of all air vents when
opened.
2. Boiling Out of Boiler and System. The oil and grease which
accumulate in a new hot water boiler can be washed out
in the following manner.
a. Ideally, shut off valves have been installed between
the boiler return manifold and the rest of the system,
to minimize the amount of system draining.
b. Drain the boiler to a level below the relief valve
tapping.
DANGER
Assure that the boiler is at zero pressure before
removing the relief valve. Open the safety valve
to relieve all internal pressure prior to proceeding.
Safety valve discharge piping must be piped such
that the potential for burns is eliminated.