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Owner's of the A.O. Smith Boiler NW 37-670 gave it a score of 0 out of 5. Here's how the scores stacked up:
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4. Close the vent as water starts to flow from the opening. Place the
make-up water valve in the desired position. The boiler is now
ready for START UP and TEMPERATURE REGULATION if being
placed in operation for the first time.
START UP
The following checks should be made by the installer when the boiler
is placed into operation for the first time:
1. Check all factory and field made water and electrical connections
for tightness.
• Repair water leaks and tighten electrical connections
as necessary.
2. Turn on the electrical disconnect switch and pilot switch(es)
mounted on the boiler cabinet.
3. Observe the operation of the boiler during the first heating cycle.
• Temperature control and contactor operation should be
checked by allowing the boiler to come up to temperature
and shutoff automatically.
TEMPERATURE REGULATION
Always turn off the electricity at the electrical disconnect switch when
making a temperature control adjustment.
It is suggested the temperature adjustment be turned to the lowest
setting which satisfies the hot water requirements of the system.
• Additional instructional literature is provided with the boiler for
adjusting this control.
Always close and lock the cabinet door after making a temperature
adjustment. Turn on electricity.
DRAINING
The boiler must be drained if it is to be shut down and exposed to
freezing temperatures. Maintenance and service procedures may
also require draining the boiler.
1. Turn off the electrical disconnect switch.
2. Close the make-up water valve and system valves as necessary.
3. Open a nearby outlet to vent the parts of the system being drained.
4. Open the boiler drain valve.
5. If the boiler is being drained for an extended shutdown, it is
suggested the drain valve be left open during this period.
• Follow FILLING instructions to restore boiler to service.
MAINTENANCE
Boiler maintenance includes periodic tank flushing and cleaning, and
removal of lime scale from the heating elements. Circulating pumps
should be oiled.
MAINTENANCE SCHEDULE
Component Operation Interval Required
Flushing Monthly
Tank Sediment As Needed
Removal
Lime Scale As Needed UN•LIME
®
Elements Removal Delimer and
element
gaskets.
Circulating Oiling Per pump makers
Pump(s) instructions
Tank flushing and circulating pump lubrication should be performed
in accordance with the above schedule. Tank sediment removal and
element lime scale removal must be performed when needed as
determined by period inspections. Following are the instructions for
performing recommended maintenance.
FLUSHING
1. Turn off the electrical disconnect switch.
2. Open the boiler drain valve. Allow water to flow to an open drain
until it runs clean. Do not come in contact with the water being
drained as it may be very hot.
3. Close the drain valve when finished flushing.
4. Turn on the electrical disconnect switch.
SEDIMENT REMOVAL
Water borne impurities consist of fine particles of soil and sand which
settle out and form a layer of sediment on the bottom of the tank. In
time, if not removed, the level of sediment might reach the heating
elements.
For convenience, sediment removal and element lime scale removal
should be performed at the same time as follows:
WATER AND LIME SCALE REMOVAL
Water and lime scale accumulations on the heating elements is a
normal condition, common to all immersion type elements. Factors
which affect the amount of this formation are:
1. Amount of make-up water used. As the volume of make-up water
heated increases, more scale results.
2. Water temperature. As the temperature of the water is increased,
more scale is deposited on the elements.
3. Characteristics of water supply. Regardless of water treatment,
the elements should be examined regularly.
Water scale accumulations may cause noises to occur during
operation.
It is recommended that a lower heating element be removed
periodically for examination. If it is scaled, all of the elements should
be removed and cleaned. If the tank bottom has an accumulation of
sediment, it should be cleaned.
Lime scale should be removed from the elements by dissolving the
accumulation in UN•LIME
®
delimer. UN•LIME is a non-muriatic
delimer, available through your dealer or distributor. Do not use muratic
or hydrochloric acid base deliming solutions to remove lime scale
from the elements. Do not pour delimer into tank.
All models:
1. Turn off electrical disconnect switch.
2. Drain the boiler following DRAINING instructions.
3. Remove the cabinet panel which covers the heating elements.
• Remove insulation as necessary to reach the element
area.
4. Remove the bolts from each element and remove the elements
from the opening.
• Disconnect element wiring as necessary.
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