Lochinvar 502 - 2072, 402 - 2072 service manual G Anti-cycling

Models: 502 - 2072 402 - 2072

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G: Anti-cycling

Copper-fin II/IIE Boiler, Water Heater and Pool Service Manual

1 Service (continued)

F6: Outdoor air shutdown differential

The outdoor air shutdown differential parameter is the number of degrees below parameter F5 the outdoor air temperature must go before the unit will respond to a SH demand. This parameter can be changed by the user or the installer by accessing parameter F6. The temperature range of this parameter is 0°F (0°C) to 90°F (50°C). The default value is 10°F (5°C).

F7: Shift reset curve

The shift reset curve parameter shifts the actual set point above or below the calculated set point the number of degrees in this parameter. This parameter can be changed by the installer by accessing parameter F7. The temperature range of this parameter is -27°F (-15°C) to 27°F (15°). The default value is 0°F (0°C). This feature will be active if this parameter is set to anything other than 0°F (0°C).

F8: Boost temperature

If a SH demand lasts longer than the programmed time delay setting (F9) and there have been no DHW demands, the control will increase the SH set point by the amount in this parameter. If the SH demand continues through another time period, the set point will be increased again. This will continue until either the SH demand ends, a maximum of 20 increases has occurred, or the SH user set point has been reached. Once the SH demand has been satisfied the set point will revert back to its calculated setting. The boost temperature can be changed by the installer by accessing parameter F8. The temperature range of this parameter is 0°F (0°C) to 45°F (25°C). The default value is 0°F (0°C). This feature will be active if this parameter is set to anything other than 0°F (0°C).

F9: Boost time

The boost time parameter sets the amount of time that must elapse with a SH demand before the water temperature set point will be increased. This parameter can be changed by the installer by accessing parameter F9. The time range for this parameter is 1 minute to 250 minutes. The default value is 20 minutes.

G: Anti-cycling

G1: Anti-cycle delay

Once a SH demand has been satisfied, a set amount of time must elapse before the control will respond to a new SH demand. The control will block the new heat demand and anti-cycling will be shown in the display until the time has elapsed or the water temperature drops below parameter G2. This parameter can be changed by the installer by accessing parameter G1. The time range for this parameter is 0 minutes to 40 minutes. The default value is 1 minute.

G2: Anti-cycle override differential

The control will bypass the anti-cycling time if the water temperature drops too quickly. The control will use the water temperature at the time it shut off as the starting point.

If the temperature drops below the temperature parameter the control will abort anti-cycling and allow the unit to fire. This parameter can be changed by the installer by accessing parameter G2. The temperature range of this parameter is 0°F (0°C) to 54°F (30°C). The default value is 10°F (5°C).

G3: Ramp delay enable

When the ramp delay on/off parameter is active, the ramp delay limits the boiler firing rate when a SH cycle has started. There are six (6) limiting steps used to limit temperature overshoot and short cycles, see FIG. 1-2 on page 19 of this manual. This feature can be turned on or off depending on the installation. This parameter can be changed by the installer by accessing parameter G3. The control range of this parameter is 0 = Off, 1 = Ramp Up Only, and 2 = Ramp Up and Ramp Down. The default value is 0.

G4: Ramp delay settings

When ramp delay is active, there are up to six (6) limiting steps, as described above in Ramp Delay On/Off. Each step has its own time period and modulation limit. The installer can adjust these settings by accessing parameter G4. The settings for each step are displayed as follows:

G4 Ramp n

mm minutes ppp.p%

Where n is the number of the step, mm is the length of time in that step, and ppp.p is the maximum firing rate allowed during that step. Upon selecting this parameter, the ramp number n will be flashing. Use the UP and DOWN keys to select the step you wish to adjust. Use the NEXT and PREVIOUS keys to select the setting you wish to adjust. Use the UP and DOWN keys to adjust the value of each setting.

NOTE THAT THE FIRING RATE LIMIT IN STEP 6 WILL APPLY THROUGHOUT THE ENTIRE CALL FOR HEAT. If 100% rate is required, the rate limit in step 6 must be 100%. The default values are 2 minutes at 50% for step 1, 1 minute at 80% for step 2, and 1 minute at 100% for steps 3 through 6.

G5: Minimum on / off stages 1, 3

Whenever Stage 1 or Stage 3 (if used) starts or stops, a timer is started. This timer must expire before that stage can turn off or back on. To adjust this time delay, access parameter G5. The range of this parameter is 0 to 255 seconds. The default value is 60 seconds.

G6: Delay between stages 1, 3

Whenever Stage 1 or Stage 3 (if used) turns on, a timer must expire before another Stage 1 or 3 can turn on, whether in the same heater, or in another heater in a Cascade. To adjust this time delay, access parameter G6. The range of this parameter is 0 to 255 seconds. The default value is 60 seconds.

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Lochinvar 502 - 2072, 402 - 2072 service manual G Anti-cycling