LAARS Horizon - Installation, Operation and Maintenance Instructions - Manual (Page 4)

Page 4
LAARS Heating Systems Company
1L. Oil
Use only No. 2 Heating Oil. Do not use gasoline,
crankcase draining or any oil containing gasoline.
1M. Oil Storage and Pipe Layout
(See Figures 3 and 4)
Figure 3: One-pipe system - pipe and tank layout.
Figure 4: Two-pipe system - pipe and tank layout.
1N. Electrical Connections
All electrical wiring must conform to local codes
and/or the National Electrical Code ANSI / NFPA No.
70 - Latest Edition. The system must be electrically
grounded in accordance with the requirements of the
authority having jurisdiction or, in the absence of such
requirements, with the National Electrical Code
mentioned above.
1O. Operation
(using Honeywell L.8124A
aquastat relay)
A call for heat from the room thermostat causes
the relay to “make” the burner circuit and also feed
the circulator, provided the boiler water temperature is
above the low limit setting (usually 190° to 210°F).
The burner and circulator then continue to run until
the room thermostat is satisfied.
A high limit switch shuts off burner in the event
of water temperature exceeding the high limit setting,
usually 20° to 30°F above the low limit setting.
The low limit switch and circulator maintain
boiler water temperature for domestic hot water
service and prevents circulation of heating system
water if domestic water is not hot enough.
1P. Domestic Water Piping
Connect hot water tempering valve (12) “HOT”
port to hot water outlet from unit. This valve should
be mounted 8" to 12" below the outlet and set for
120°F mixed delivery temperature or as local codes
dictate.
Connect gate or shutoff valve (13) to tempering
valve (12) “MIX” port, and cold water inlet.
Connect pressure relief valve (11) (if required by
codes), maximum 150 PSI as close to the unit as
possible. No other valves or restrictions may be
installed between the DHW coil and the relief valve.
(DO NOT USE A TEMPERATURE/
PRESSURE RELIEF VALVE AS THIS IS NOT A
STORAGE HOT WATER HEATER).
SECTION 2.
Maintenance
WARNING
Flue gases are dangerous - do not operate boiler if
there is an escape of flue gas. Call a qualified
serviceman and have the entire flue and venting
system inspected.
2A. Cleaning the Boiler
To maintain the high thermal efficiency and a
long life from your boiler, it should be cleaned at least
once a year, preferably at the end of the heating
season. This is particularly important as rusting can
occur when the boiler is idle.
It is recommended that a service contract be
arranged with a properly equipped serviceman who
will be able to do the job efficiently and without mess.
1.
Switch off electrical supply to the boiler.
2. Remove front cleaning cover.
3. Remove flue baffles and thoroughly brush out
flue tubes.
4. Remove flue deposits from flue collector box
using a vacuum nozzle through side cleaning
ports.
5. Vacuum out accumulated deposits from
combustion chamber through cleaning cover
opening.
6. Replace all parts, ensuring flue baffles are
correctly located and cleaning cover is tightly
sealed.
2B. Cleaning the Chimney
Sweep all soot deposits from chimney and
smoke-pipe once a year, preferably at the end of the
heating season. It is also advisable to inspect the
chimney and smoke-pipe at the beginning of heating
season as birds may have built their nest inside or
other material may be causing a blockage.
2C. Servicing the Burner
This should only be carried out by a trained and
licensed service technician in accordance with the
burner maker’s instructions.
B
O
I
L
E
R
11
12
13
8 - 12"
Figure 1.
OUT OF
PRODUCTION