Sequence of Operation
On call for heat, the
Start Up Procedures
The water system, the gas system and the electrical system for the heater should be completed and checked as per the heater installation manual and associated documents.
1.Turn on power to the heater with the manual main gas valve and pilot gas valve off. The electric power supply requirements are:
a.
120/240 volt 60Hz 1.0/1.95 Amp fan motor for models
2.Check power connections.
3.Close heater power switch.
4.Set operating control to call for heat.
a.Fan motor starts, draft proving switch clos- es.
b.Heater pump starts, flow switch closes.
c.Ignition module energized.
d.Check for spark at gas pilot.
5.Turn operating control to end call for heat.
6.Wait a minimum of 60 seconds.
7.Open pilot gas valve.
a.Repeat procedure outlined in #4 above.
8.After pilot gas is proven and main safety
a.Main burners will ignite.
9.Heater will operate until call for heat is satisfied.
10.Restart unit and visually check all components for proper operation.
11.Check all vent connections and joints for leakage. Correct if found.
12.To restart unit after a failure, follow the procedures outlined above and other subsequent or related sec- tions outlined in the heater manual.
EMERGENCY SHUTDOWN: SHUT OFF ALL POWER AND GAS, CALL GAS UTILITY.
Draft Proving Switch
The draft proving switch insures that the blower is operating. The switch is in the limit circuit and does not allow the ignition module to operate unless it is closed.
NEGATIVE PRESSURE
CONNECTOR
Fig. 7: Draft Proving Switch
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