LAARS EDN Series - Installation, Operation and Maintenance Instructions User Manual

Page 25

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Endurance

Page 25

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 “unI” 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

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