Roberts Gorden UHD[X][S][R] 150 - Manual (Page 28)

UHD S TANDARD D UCT F URNACE I NSTALLATION O PERATION AND S ERVICE M ANUAL
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Figure 11: Automatic Burner Control Sequence
Figure 12: Gas Valve
Burner Sequence for Ignition Control
Flame Signal
Start Gas Valve
Ignition Spark
Thermostat 24 V
SHUT DOWN RUN START
ts = 10 Seconds
Signals Output By Control
Required Incoming Signals
Flue Blower
Pressure
Switch
P
C
NO
NC
30 Seconds Purge*
*Purge time begins at pressure switch change over.
30 Seconds Post Purge
If at any stage the flame fails, the control will retry
for ignition. The control has four trials for ignition
before a one hour lockout.
½PSI
IN
C
ON
OFF
Regulator
Outlet
Pressure
Gas Inlet
Inlet Pressure
TOP VIEW END VIEW
Description Part Number
Gas Valve 150 - 225 NG 90032505
Gas Valve 150 - 225 LP 90032506
Gas Valve 250 - 400 NG 90032520
Gas Valve 250 - 400 LP 90032521