38
Table 8.3: Pump Modes
Pump
Mode
Display Text Brief Description
Detail
Section
Page
0 DHW or CH & DHW pump
The General pump is on when the CH pump runs on CH demand.
The DHW pump runs on DHW demand. Either the CH or DHW pump
runs; they never run at the same time.
8.C.1 40
1 General pump with 3-way valve
The General pump is always on when burner is on. A line voltage
(120 VAC) 3-way valve is operated to supply water to the DHW tank.
8.C.1 41
2 Manifold with pump for DHW
The General pump is always on when the burner is on. The CH
pump runs on CH demand. The DHW pump runs on DHW Demand.
Either the CH or DHW pump runs; they never run at the same time.
8.C.1 41
A. CONTROL OVERVIEW
The PUREFIRE
®
boiler control is one of the primary safety
devices for the boiler. It controls the ignition sequence,
temperature limits, circulators and gas flow to the boiler. It
also provides many unique features.
The control provides 7 central heating modes and 3
domestic hot water modes. In addition, the boiler can be
adapted to several different piping schemes using the 4
different pump modes.
To provide maximum flexibility, several special features
are also included.
1. Central Heating (CH) Modes:
The P
UREFIRE
®
boiler control allows the installer to
choose from several different central heating modes.
The following table shows the central heating modes. In
addition, the table shows the display text associated with
each CH mode and a brief description of the operation.
2. Domestic Hot Water (DHW) Modes:
The P
UREFIRE
®
boiler control also allows the installer
to choose from three different DHW modes.
3. Pump Modes:
The P
UREFIRE
®
boiler allows three different pump
modes to give the installer flexibility in piping
arrangements.
BOILER CONTROL: INTERNAL WIRING & OPERATION
Table 8.1: Central Heating Modes
8. BOILER CONTROL: INTERNAL
WIRING & OPERATION
CH
Mode
Display Text Brief Description
Detail
Section
Page
0 Indoor Thermostat
Call-for-Heat signal from thermostat with user selected boiler supply target set-
point temperature.
8.D.1 42
1 Thermostat and Outdoor Reset
Call-for-Heat signal from thermostat with boiler supply target temperature cal-
culated using outdoor temperature.
8.D.1 42
2
Permanent Demand and
Outdoor Reset
Continuous heat demand with boiler supply target temperature calculated
using outdoor temperature. Thermostat input used for setback.
8.D.1 42
3 Permanent Demand
Continuous heat demand with user selected boiler supply target temperature.
Thermostat input used for setback.
8.D.1 42
4
0-10 V Input to modulate
Setpoint
Requires PFA-1 Interface Adapter. Allows 0-10 volt input from an external
source (ie. building management system) to change setpoint temperature.
8.D.1 42
5 0-10 V Input to modulate Rate
Requires PFA-1 interface Adapter. Allows 0-10 volt input from an external
source (ie. boiler sequencing control) to change input firing rate.
8.D.1 43
6 Hydro-Air Unit
Call-for-Heat signal from a thermostat with user selected supply target setpoint
temperature optimized for hydro-air heating system.
8.D.1 43
Table 8.2: Domestic Hot Water (DHW) Modes
DHW
Mode
Display Text Brief Description
Detail
Section
Page
0 No DHW No domestic hot water tank is used. 8.E.1 45
1 DHW store with sensor
The domestic hot water tank is equipped with a temperature sensor. The
PUREFIRE
®
control modulates the boiler firing rate based on tank temperature.
8.E.1 45
2 DHW store with thermostat
The domestic hot water tank is equipped with a thermostat. The PUREFIRE
®
control responds to the demand from the thermostat and modulates the boiler
firing rate targeting the DHW boiler setpoint.
8.E.1 46
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