Install Instructions

63
TABLE 9: EXTERNAL LOW LIMIT,
PARAMETER ZC_= ELL
Call for Heat Circulator Status
T-T
Input
ZR
Input
C1
Output
ZC
Output
off off off on
on off on on
on on off off
off on off off
Call for Heat Circulator Status
T-T
Input
ZR
Input
C1
Output
ZC
Output
off off off off
on off on off
on on on on
off on off on
TABLE 8: ZONE REQUEST, PARAMETER ZC_= ZR
SECTION XII: OPERATING (CONTINUED)
ii. When ZC_ is set equal to Zone Request (ZR)
When there is no IWH the Cold Start Boiler
Control “ZC” output may be congured
to control a second heating zone. This is
particularly helpful when the home uses
only two heating zones. The Cold Start
Boiler Control replaces the need for a two
circulator zone panel. When DHW Terminal
Function (dh_) is set to ZR the boiler
control’s two circulator outputs are used
to control two independent heating zones.
Refer to Table 8. A "TT" input causes a call
for heat and energizes the System Circulator
output to service heating zone 1. A second
zone’s thermostat may be wired to the "ZR"
input to energize heating zone 2 circulator
wired to the "ZC" output. Both outputs
function independently, "TT" input controls
only the System Circulator output and the
"ZR" input controls only the "ZC" output.
Both inputs cause a boiler call for heat.
The Warm Start Boiler Control with ZC_
set equal to Zone Request (ZR) energizes
the "ZC" terminal while the boiler is warm
as described earlier in this section (refer
to Paragraph A, Step 2, Item f). The "ZR"
input is a call for heat that starts the boiler.
iii. External Low Limit, Parameter ZC = ELL
The Cold Start Boiler Control is capable of
functioning as a warm start control when
external limit control is installed that closes
a contact when boiler water temperature
falls below a setpoint. When an external
limit contact closes (boiler water is cold)
the boiler is started and the "ZC" and "C1"
output terminals are de-energized. When
the "ZR" terminal is de-energized (boiler
water temperature is above setpoint) the call
for heat is ended and the "C1" terminal is
released to operation and the "ZC" terminal
is energized. An External Low Limit
Request is detected by sensing a voltage on
the "ZR" terminal. The Warm Start Boiler
Control does not have the External Low
Limit Option. Refer to Table 9.
B. STEAM BOILERS SEQUENCE OF
OPERATION
Upon a thermostat call for heat, when provided, the
R8239A Control Center Relay or the Oil Primary
Control is energized when the steam pressure is below
the L404F Pressure Limit and water level is above the
Low Water Cut-Off. When energized the Oil Primary
Control starts the burner as follows; blower is started
and operates for a pre-purge time; spark is energized
and fuel valve is opened for ignition trail time; the fuel
valve remains open when ame is proven. The burner
res until the thermostat is satised or the Pressure
Limit setting is reached. The Oil Primary Control stops
the burner by closing the fuel valve and operating the
blower for post-purge time. Upon a drop in pressure,
steam pressure below the L404F Pressure Limit, the
burner will re-start if the thermostat is still calling for
heat. When there is a tankless heater included and
there is no demand for heat, the L4006A operating
control will maintain the boiler water temperature at
the selected setting for proper operation of the domestic
water heater.
The probe low water cut-off will shut down the burner
after a 10-15 second delay, if the water level in the
boiler drops below the probe level. The Hydrolevel
CG450 low water cut-off will shut down the burner
for 90 seconds every 10 minutes of ring time to allow
water level to stabilize. If the water level is too low the
burner will not be allowed to restart. The low water
cut-off will reset and restart the burner with a call for
heat a few seconds after the water is returned to its
normal level.
On burner start, if the CAD cell does not see ame
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 ame is lost while the
burner is ring, 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,
ame is not detected, primary control will enter into
restricted mode. Restricted mode is reset by holding
down the reset button for 15 seconds.