Use and Care Manual

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110637-01 - 5/20
RRO Installation & Service Manual
10 Operating
A. WATER BOILERS SEQUENCE OF
OPERATION
1. Water Boilers Without Tankless Heaters
(Cold Start), Sequence Of Operation:
a. The RRO Boiler is equipped with a Cold
Start Intelligent Oil Boiler Control (Cold
Start Boiler Control). The Cold Start Boiler
Control replaces the traditional electronic
aquastat and circulator relays and adds
energy saving thermal purge features.
Energy is saved by starting the circulator
and delaying the burner start when there is
residual heat available in the boiler.
b. The boiler’s sequence of operation is shown
as Status Codes on Cold Start Boiler Control
display. See Table 10-2 and Figure 10-1.
c. When the thermostat calls for heat the
boiler control starts the system circulator
and the thermal purge (circulator pre-purge
time) begins. If the time is completed or
boiler temperature is less than the Start
Temperature (140 F default) the start
sequence continues by energizing the oil
primary to operate the following sequence:
blower is started and operates for pre-
purge time; spark is energized and fuel
valve is opened for ignition trial time; burner
fires until the thermostat is satisfied.
d. If the thermostat is not satisfied and the
Operating Setpoint (SP) is reached the
system circulator will continue to operate
and the burner will stop. When the boiler
water temperature drops below the setpoint
less the differential setting the burner will
restart.
e. After the thermostat is satisfied the burner
and circulator are stopped.
f. When an indirect water heater aquastat call
for heat is wired to the “ZR” terminal the
Boiler Control starts a domestic hot water
circulator connected to the “ZC” terminal
and when the boiler temperature is less
than Operating Setpoint (SP), the Cold Start
Boiler Control energizes the oil primary to
turn on the burner without circulator pre-
purge delay.
g. On burner start, if the CAD cell does not
see flame within approximately 15 seconds,
primary control will shut down the burner
and enter into a lockout mode. A lockout is
reset by pressing the reset button located
on the primary control. If the flame is lost
while the burner is firing, the primary control
shuts down the burner, enters a 60 second
recycle delay, and repeats the ignition
sequence. If after three (3) trials for ignition,
flame is not detected, primary control will
enter into restricted mode. Restricted mode
is reset by holding down the reset button for
15 seconds.
2. Water Boilers with Tankless Heaters (Warm
Start), Sequence Of Operation:
a. The RRO Boiler is equipped with a Warm
Start Intelligent Oil Boiler Control (Warm
Start Boiler Control). The Warm Start Boiler
Control replaces the traditional high and low
limit aquastat and circulator relays.
b. The boiler’s sequence of operation is shown
as Status Codes on Warm Start Boiler
Control display. See Table 10-2 and Figure
10-1.
c. When the thermostat calls for heat the
Warm Start Boiler Control starts the system
circulator and the start sequence continues
by energizing the oil primary to operate
the following sequence: blower is started
and operates for pre-purge time; spark
is energized and fuel valve is opened for
ignition trial time; burner fires until the
Figure 10-1: Intelligent Oil Boiler Control
Status Codes Displayed in  Mode

Status Description

Standby
(burner off,
pump off)
No call for heat detected

Standby
(burner off,
pump on)
Either condition is true:
a. Call for heat detected and boiler
temperature higher than operating
setpoint.
b. Call for heat detected and boiler
temperature higher than 140 F and
Pump Pre-Purge Time has not
expired.

Running
The burner runs until the call for heat is
satisfied.

Self Test
Control internal checking
Table 10-2: Sequence of Operation