To Turn Off Heater; To Shut Down System; Section 4. Maintenance; Pilot Safety Relay - Natco VW Installation And Operating Instructions Manual

Pilot Reset
Switch
Figure 22 – Pilot Safety Relay
b. For heaters with the temperature controller
bulb at the inlet, set the high-limit 40 to 50 F
above temperature controller setting.
c. If the temperature control sensing bulb is in
the heater outlet, set the high-limit switch 15
to 25 F above the temperature controller
setting.
d. Model IW Water Temperature Adjustment
Set the temperature controller (modu-snap valve)
dial to the desired service water temperature (see
Table V). Keep in mind that there is no storage
tank with the Model IW heater, therefore it will
produce its maximum capacity regardless of the
temperature setting. Excessive hot water use
will cause a drop in the temperature, but
increasing the controller setting will not change
the delivered water temperature. It could
create the very dangerous hazard of scalding a
user in the bath or shower. Make sure the water
temperature settings comply with local codes.
3D.

To Turn Off Heater:

1. Turn off main electric switch.
2. Close all manual gas valves.
3E.

To Shut Down System:

To shut down heater, turn off all manual gas valves
and electrical disconnect switches. Whenever danger
of freezing exists, shut off water supply and remove
drain plug in the bottom of front header cover. Drain
every part of system subject to freezing temperature.
Section 4
Maintenance
1. Lubricate the water circulating pump (see
instructions found on the pump).
2. If a strainer is employed in a pressure reducing
valve or in piping, clean it every six (6) months.
3. At start-up and every six (6) months thereafter,
the pilot and main burner flame should be
observed for proper performance (see Figure
23). See attached lighting and shut-down
instructions for proper pilot flame pattern). If
flame has the appearance of "sooting" tips, check
for debris near orifices. Call serviceman.
4. Inspect the venting system for obstruction,
leakage and corrosion at least once each year.
5. Keep heater area clear and free from combustible
material, gasoline and other flammable vapors
and liquids (see Table I for minimum
clearances).
6. Be certain all combustion air and ventilation
openings are unobstructed.
7. Check for fouling on the external surfaces of the
heat exchanger every six months. (NOTE: After
installation and first start-up, check the heat
exchanger for fouling after the following periods
of operation: 24 hours, 7 days, 30 days, 90 days,
and once every six months thereafter).
Fouling on the external surfaces of the heat
exchanger is caused by incomplete combustion
and is a sign of combustion air and/or venting
problems. As soon as any fouling is observed,
the cause of the fouling should be corrected (see
Section 5, Troubleshooting Guide). The heat
Figure 23 – Main Burner Flame Pattern
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