Endurance
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6.4. These do not show on the control display, but it is
helpful to know how they affect the control logic of
the Endurance units.
6.5.1 ACV Release (EBP only)
When the EBP is in tank charge mode, and there
is a call for space heating, the EBP needs to know at
what temperature it can release the ACV (anti-
condensing valve) back to the space heating position,
allowing the hot water to go into the system. The ACV
release point is the “burner off” point minus 5°F
(3°C). For example, if the “burner off” point is 190°F
(88°C), the ACV release point is 185°F (85°C). This
means that when the supply temperature reads 185°F
(85°C) in the tank, it will release the ACV for heating
mode.
6.5.2 Tank Charge Setting (EBP only)
When the temperature at the tank sensor goes
below the tank charge setting, the EBP will be in “tank
charge” mode. The tank charge setting equals the
programmed “burner off” point minus a fixed 40°F
(22°C) differential. For example, if the “burner off”
point is 190°F (88°C), the EBP will go into “tank
charge” mode when the tank sensor reads below 150°F
(66°C). The ACV will close, and the EBP will run to
bring the supply temperature up to 185°F (85°C), and
the ACV will be released back to the space heating
mode (as long as there is no call for domestic hot
water).
6.5.3 Burner On Point
The “Burner On” point is calculated by
subtracting the “Burner On Differential (Dif)” from
the “Burner Control Point.” For EBP units the
differential is fixed at 13°F (7°C) and for EDP/EDN
units, it is adjustable (shown as “Dif” in the setup
menu) from 4°-30°F (2°-17°C). This value tells the
Endurance when to re-energize during a call for heat
in which the Endurance reached its “Burner Off
Point.”
6.5.4 Modulation Point
During a call for heat, the Endurance will ignite
at low fire and will begin to modulate to match the
load as it approaches the “Burner Control Point.”
There is no fixed temperature when this will occur,
and this value is not displayed on the Endurance.
6.6 Other Control Functions
6.6.1 Using Buttons on Control
Figure 30 shows a drawing of the control,
including the placement of the four buttons. Table 4
shows the actions associated with each of the buttons.
6.4.5 “Oal” Minimum Outdoor
Reset Point
The “Oal” parameter tells the controller what the
minimum allowable supply temperature can be,
regardless of the outdoor reset calculation.
For EDP/EDN units, the default setting is 170°F
(77°C) and it is adjustable 155-200°F (68-93°C).
For EBP units, the default setting is 170°F
(77°C) and it is adjustable 170-200°F (77-93°C). Note
that the difference between EBP and EDP/EDN
adjustment ranges is because the EBP units must be
able to keep the transfer tank at a high enough
temperature to generate the domestic water through
the DHW heat exchanger.
6.4.6 “rc” Outdoor Reset Ratio
The outdoor reset ratio is shown as “rc” in the
display. The ratio determines part of the relationship
between the outdoor temperature and the Endurance
supply temperature. It is adjustable between 0.1 and 5.
The reset number represents the increase in the
Calculated Setpoint (CSP)for every degree below the
warm outdoor shutdown temperature.
The boiler control calculates CSP = Oal + (oTo –
air temp) x rc.
6.4.7 “oTo” Warm Outdoor Shutdown
When in the outdoor reset function is on, the
control has the ability to shut down the boiler system
when the outdoor temperature sensor reads the “oTo”
temperature that is set. This parameter is adjustable
from 55°-70°F (13°-21°C) and has a default setting of
65°F (18°C). The warm outdoor shutdown feature
will, of course, not affect the generation of domestic
water in the EBP models.
6.4.8 “un
I
” Temperature Units
The control has the ability to display and be
programmed in both °F (Fahrenheit) or °C (Celsius).
The “unl” lets the user choose between °F and °C.
6.4.9 “Dif” Burner On Differential
The differential between the Burner Control
Point and the Burner On Point is shown as “Dif” in the
display. If the Endurance reaches the Burner Off Point
during a call for heat, and the call for heat continues,
this differential will determine at what point below the
Burner Control Point the Endurance will energize
again. In the EBP models, this differential is fixed at
13°F (7°C) to ensure that the transfer tank will be
properly charged. In the EDP/EDN models, this
differential is adjustable 4°-30°F (2°-17°C).
6.5 Calculated Control Values
There are several control values that are not
directly set by the user, but are calculated by the boiler
control, once the user has set the parameters in Section
