PEERLESS PUREFIRE PFW-199, Installation, Operation & Maintenance Manual

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b. DHW Pump Post Purge:
After the storage tank is satisfied and the
combustion blower post-purge stops, the control
will continue to run the DHW Circulator (Terminals
#21 & 22) until the difference between the supply
and return temperatures on the boiler are less than
TDiff from screen #3 (Figure 8.35). The time that
this circulator runs is limited by the value of Max
DHW Pump Postpurge Time selected on Screen
#2 (Figure 8.34).
Table 8.5 shows the range and default values for
both the Max DHW Postpurge Time and Min.
Supply/Return Temperature Difference (TDiff).
c. Installation Location & Vent Material:
To determine the suitable maximum vent
temperature limit, the boiler control uses the
Installation Location and the Vent Material. Screen
#4, shown in Figure 8.36, allows selection of the
Installation Location. Screen #5, shown in Figure
8.37, allows selection of the Vent Material.
Table 8.6 shows the vent temperature limit based
on vent material and installation location (due to
National Codes).
If the vent temperature approaches the vent
temperature limit, the control will reduce the input
rate of the boiler. If the input rate is at its
minimum (1% of modulation) and the vent
temperature is still at or above the limit
temperature, the control will turn off the boiler. An
error code of E30, High Stack Temperature, will
be displayed.
The minimum signal that the control can read
from the vent temperature sensor is 50°F (10°C). If
the vent temperature falls below this, the boiler
will monitor the boiler supply and return
temperatures while it is firing. If the water supply
temperature is below 120°F (49°C) and the return
temperature is below 80°F (27°C) the boiler will
operate normally. If either of these temperatures
exceed the indicated value, the control will limit
the boiler input to minimum firing rate (1% of
modulation). This is done to prevent overheating
of the exhaust vent material.
d. Freeze Protection:
This feature is intended to protect from freezing
temperatures in the boiler system. If the supply
temperature drops below the freeze protection
starting point, the DHW pump (Terminals #21 &
22) are activated. If the supply temperature drops
more than 9°F (5°C) below this temperature, the
control starts the burner and operates it at it
minimum input rate (1% of modulation). Figure
8.38 shows the screen used to adjust the Freeze
Protection temperature start. This is under the
Boiler Settings screen on the Installer Menu.
Table 8.7 shows the minimum, default and
maximum temperature values for this parameter.
Figure 8.34: Maximum Pump Post-purge Time
B O I L E R S E T T I N G S 2 ▲
M a x D H W P u m p
P o s t P u r g e T i m e
6 0 s e c ▼
Figure 8.35: Min. Supply/Return Temperature
Difference
B O I L E R S E T T I N G S 3 ▲
S u p p l y R e t u r n
T D i f f
4 ° F ▼
Figure 8.36: Installation Location Selection
B O I L E R S E T T I N G S 4 ▲
I n s t a l l a t i o n
L o c a t i o n
U
S
A ▼
Figure 8.37: Vent Material Selection
B O I L E R S E T T I N G S 5 ▲
V e n t M a t e r i a l :
P V C ▼
Figure 8.38: Freeze Protection Starting
Temperature
B O I L E R S E T T I N G S 6 ▲
F r e e z e P r o t e c t i o
n
s t a r t s a t : 5 0 ° F ▼
Parameter Minimum Default Maximum
Freeze Protection start at: 45°F (7°C) 50°F (10°C) 56°F (13°C)
Table 8.7: Freeze Protection Value Range
BOILER CONTROL: INTERNAL WIRING & OPERATION
Table 8.6: Vent Temperature Limit Parameters
Vent Material
Installation Location
USA (Default) Canada
PVC (Default) 190°F (80°C) 149°F (65°C)
CPVC 230°F (110°C) 190°F (80°C)
Polypropylene 230°F (80°C) 230°F (80°C)
Stainless Steel 250°F (80°C) 250°F (80°C)
Table 8.5: DHW Pump Purge Parameters
Parameter Minimum Default Maximum
Max DHW Pump
Postpurge Time
0 sec (pump post-
purge disabled)
60 seconds 255 seconds
Min. Supply/Return
Temp. Difference
0°F 4°F 18°F