Use and Care Manual

35
110637-01 - 5/20
RRO Installation & Service Manual
A. MAINTENANCE OF LOW WATER CUT-OFF
DEVICES
WARNING
Probe and float 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.
It is important to physically remove the probe
from the boiler 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 boiler tapping.
f. Inspect that portion of the probe that is
exposed to the boiler 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 (Teflon) tape.
j. Screw the probe into the boiler tapping.
k. Mount the low water cut-off control on the
probe.
l. Reconnect the control to probe wiring.
m. Fill the boiler to its normal waterline.
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 check out procedure.
B. BOILER AND SYSTEM CLEANING
INSTRUCTIONS FOR TROUBLE FREE
OPERATION
NOTICE Check with local authorities or consult
local water treatment services for acceptable
chemical cleaning compounds.
1. WATER BOILERS
a. 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.
b. 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.
i. Remove relief valve using extreme care
to avoid damaging it.
ii. Add an appropriate amount of
recommended boil out compound.
iii. Replace relief valve.
iv. Fill the entire system with water.
v. Start firing the boiler.
vi. Circulate the water through the entire
system.
vii. Vent the system, including the radiation.
viii. Allow boiler water to reach operating
temperature, if possible.
ix. Continue to circulate the water for a few
hours.
11 Maintenance and Service Instructions
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