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LAARS HEATING SYSTEMS
storage level is not below the fuel unit. A two pipe
system of not less than 3/8" OD copper tubing is
recommended when lowest fuel level is below but not
more than 8 feet below fuel unit.
Important:
Refer to burner (pump) instructions
for detailed fuel line and pump usage information. All
installations must conform to local and national codes.
See Figures 5A and 5B.
Figure 5A One-pipe system - pipe and tank layout.
Figure 5B Two-pipe system - pipe and tank layout.
1M. Electrical Wiring
All wiring must comply with the National
Electrical Code, NFPA 70, local codes and ordinances
regarding wire size, type of insulation and enclosures
etc. (see Figure 6).
1N. Operation
(Honeywell L8124A 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°F [88°C] to
210°F [99°C]). 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°F (-7°C) to 30°F (-1°C) above the low limit
setting.
The low limit switch and circulator maintain
boiler water temperature for domestic hot water
services and prevents circulation of heating system
water if domestic water is not hot enough.
1O. Domestic Water Piping
1.
Connect anti scald tempering valve (12) “HOT”
port to hot water outlet from unit. This valve
should be mounted 3" (76mm) to 6" (152mm)
below the outlet and set for 120° F mixed
delivery temperature or as local codes dictate
(see Figure 1).
2.
Connect gate or shutoff valve (13) to anti scald
tempering valve (12) “MIX” port, and another to
the cold water inlet.
3.
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).
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.
1P. 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 smoke-pipe from boiler.
3.
Remove top jacket panel.
4.
Unscrew the securing nuts and remove flue
collector.
5.
Remove baffles from flue tubes.
6.
Remove burner by unscrewing the flange
mounting nuts.
7.
Remove soot and scale deposits from tubes with
a flexible wire brush, taking care not to damage
“ceraform” combustion chamber, below outer
tubes.
8.
Vacuum out accumulated deposits from
combustion chamber through burner port, taking
care not to damage “ceraform” combustion
chamber, below outer tubes.
9.
Replace all parts, ensuring flue-baffles are
correctly located. Ensure flue collector and
smoke-pipe are tightly sealed.
1Q. 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.
B
O
I
L
E
R
11
12
13
3 - 6"
(76mm - 152mm)
Figure 1. Domestic water piping.
