LAARS Mighty Therm VW-PW (Sizes 175-400) - Installation, Operation and Maintenance Instructions - Manual (Page 22)

LAARS Heating Systems
Page 22
3.5 Hi-Limit Switch Checkout
After running the heater for a long enough
period, bring the water temperature within the range of
the hi-limit switch and slowly back off the high limit
setting until the heater shuts off. The main burners
should reignite when the hi-limit switch is reset and
turned back up to its original setting. The heater
should now run until it shuts off automatically on
operating control.
Should overheating occur or the gas supply fail
to shut off, turn off the manual gas control valve to the
heater.
3.6 Shut-Down Procedure
Shut down the heater following the instructions
found on the inside of the heater.
Where there is a danger of freezing, shut off the
water supply and remove the drain plugs on both sides
of the heater jacket. Drain every part of the system
subject to damage from freezing temperatures.
Figure 31. Burner removal.
3. At startup and every 6 months after, look at the
pilot and main burner flame (see Figure 29). If
the flame has the appearance of sooting tips,
check for debris near orifices. Call service
technician.
4. Inspect the venting system for blockage, leakage,
and corrosion at least once a year.
5. Keep the heater area clear of combustible
material, gasoline, and other flammable liquids
and vapors.
6. Be sure all combustion air and ventilation
openings are not blocked.
7. Check for black carbon soot buildup on the
external surfaces of the heat exchanger every 6
months.
8. Do not use the heater if any part has been under
water. Replace anypart of the control system and
any gas control which has been under water.
NOTE: After installation and first startup, check
the heat exchanger for black carbon soot buildup after
the following periods of operation: 24 hours, 7 days,
30 days, 90 days, and once every 6 months thereafter.
4.2 Replacement of Gas Controls
The gas and electric controls installed on the
heaters are designed for both dependable operation
and long life. Safe operation of the heater depends on
their proper functioning.
NOTE: The warranty does not cover damage
caused by lack of required maintenance or improper
operating practices.
WARNING
Never attempt to repair the gas valve. Such
attempts will void the warranty, and could lead to
dangerous results.
SECTION 4.
Maintenance
4.1 General Instructions
1. Oil the water circulating pump in accordance
with the manufacturer's instructions.
2. If a strainer is used in a pressure reducing valve
or in the piping, clean it every 6 months in
accordance with the manufacturer's instructions.
Plug
Figure 32. Scale inspection.