Raypak D2 manual Sequence of Operation, Start Up Procedures, Draft Proving Switch

Sequence of Operation

On call for heat, the D-2 Power Vent fan (and appli- ance pump) start. When the flow switch circuits close, the ignition system consisting of an electronic spark module, pilot gas system and flame sensor, are ener- gized. When draft proving switch closes and all safety circuits are proven, the automatic main gas valves will open and the heater will operate. When the operating limit circuit is satisfied, the heater will shut down.

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. Dual-voltage fan motor.

120/240 volt 60Hz 1.0/1.95 Amp fan motor for models 181-401.

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 shut-off valve is energized.

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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