(6)A defective RA890 may be the cause but items (1) thru (5) should be followed first. Refer also to RA890 relay literature furnished with the control.
(d)By referring to the Sequence of Operations step by step operation of the system can be controlled and the cause of pilot failure can be readily found. After the cause of pilot failure has been corrected, resume normal operation by following the Lighting Instructions.
d.SHUTDOWN INSTRUCTIONS
(1)Close manual
(2)Turn off main electric switch.
9.EOP CONTROL SYSTEM – 5006B thru 5014B
The EOP Control System functionally is the same as the EO Control System. The RA890F Protectorelay, however, is installed in a prewired control cabinet along with a terminal strip, “main power” switch, “main gas valves” switch, “main power” lamp, “main gas valves” lamp and “pilot failure” lamp.
The RA890F Protectorelay Primary Control is a non- programming, amplifying relay which, when used with the Q179D Rectification Pilot (standing or continuous burning pilot), provides solid state electric Flame Safeguard Protection during a “call for heat” pilot failure. Should this occur, main burners will shut down within 0.8 second, “Main Gas Valves Lamp” will go off, the Protectorelay will lock out on safety shutdown within 15 seconds, and the “Pilot Failure Alarm Lamp” will be lighted. The thermocouple in the Q179D pilot will cool and, within 45 to 90 seconds, will cause the
Should a pilot failure occur during the “off” cycle, the thermocouple in the Q179D pilot will cool and, as described above, will shut off main gas valves and flow of gas to pilot. On the next call for heat the
Protectorelay will immediately sense the absence of pilot flame and the “Pilot Failure Alarm Lamp” will be lighted.
a.LIGHTING INSTRUCTIONS
(1)Turn off all panel switches.
(2)Turn off manual main and pilot gas valve. Wait at least five (5) minutes before proceeding.
(3)Push safety switch reset button on this panel.
(4)Turn on manual pilot gas valve. Push and hold pilot safety valve button and light pilot. When pilot is lit, proceed.
(5)Set operating control to desired temperature or pressure.
(6)Turn on Main Power Switch. Main Power Light will light.
(7)Turn on manual main gas valve.
(8)Turn on Main Gas Valve Switch to light main burners. Main Gas Valve Light will light.
SEQUENCE OF OPERATION EOP – See Fig. 51
b.NORMAL OPERATION – 5006B thru 5014B
(1)When the operating control calls for heat, terminals #6 of Panel and RA890 Relay are energized.
(2)A component self check circuit in the RA890
Relay is activated which checks the electronic network of the relay.
(3)Flame rod circuit of the RA890 and Q179D proves presence of pilot flame electronically.
(4)Terminal #5 is energized and supplies power to the main gas valves and main gas valve panel light providing “Gas Valve On Switch” is closed.
(5)Main gas valves open and main burners are lighted by pilot. “Main Gas Valve” lamp will be activated.
(6)When operating control is satisfied, terminals #6 and #5 are
(7)Pilot continues to burn.
(8)“Main Power” lamp will remain lighted.
c.SAFETY SHUTDOWN
1. SAFETY SWITCH CIRCUIT
If limit control, Low Water
2.PILOT FAILURE
(a)Flame rod supervision of pilot occurs only during the operating cycle (call for heat) of the operating control since the RA890 relay is energized by the operating control. If pilot failure occurs during this period, the main gas valves close and the main gas burners are extinguished within 0.8 second.
After 15 seconds the relay will lock out on safety shutdown and the “Pilot Failure Alarm Lamp” will be lighted.
(b)If pilot failure occurs during the “off” cycle of the operating control, the RA890F relay will not be powered thru terminal #6, therefore, there is no electronic flame rod supervision. This is due to the utilization of a thermocouple in the Q179D modified pilot.
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