Bryan Boilers Triple-Flex 150, 250, & 300, 200 service manual Demand and Rate

that way until the 4- 20mA signal is stable again.

LLCH 20MA WATER TEMPERATURE: TEMPERATURE OR NONE

CH 4MA WATER TEMPERATURE: TEMPERATURE OR NONE

These provide the 20mA and 4mA temperatures for the interpolation curve. If either of these have the None value, are invalid, are out of range, or are too close for interpolation, an alert is issued and the setpoint reverts to "Local" when it is selected as 4-20mA.

LL CH SETPOINT: DEGREES OR NONE

This setpoint is used when the time-of-day input is off. If the ODR function is inactive then the setpoint is used as-is. If the ODR function is active then this setpoint provides one coordinate for the outdoor reset curve.

LLCH TOD SETPOINT: DEGREES OR NONE This setpoint is used when the time-of-day input is on. If the ODR function is inactive then the setpoint is used as-is.

If the ODR function is active then this setpoint provides one coordinate for the shifted (because TOD is on) outdoor reset curve.

TIME OF DAY

The Time of Day has one sources of control: a switch contact. Closed TOD is an on condition; open, then TOD is off.

OUTDOOR RESET AND BOOST (BOOST IS FUTURE)

The outdoor reset and boost functions for the LL CH functions will be implemented as described for a stand-alone CH loop.

Each of the loops which implements outdoor reset and boost has its own parameters. The parameters used by the LL master are:

•LL setpoint

•LL CH TOD Setpoint

•LL Outdoor reset enable: Disable, enable

•LL CH ODR minimum outdoor degrees or None

•temperature:

•LL CH ODR maximum outdoor degrees or None temperature:

•LL CH ODR low water temperature: degrees or None

•LL CH ODR boost time: mm:ss or None

•LL CH ODR boost max setpoint: degrees or

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Date: 8-4-2010

Revision: 0

Form: 2396

None

•LL CH ODR boost step: degrees or None

•LL CH ODR boost recovery step time:mm:ss or None

The outdoor reset function requires the outdoor temperature. This temperature may be obtained from either a local sensor or a LL slave as described earlier. If the outdoor temperature is invalid and unknown, then no outdoor reset action occurs and an alert is issued indicating an invalid outdoor temperature.

LL CH ODR MINIMUM WATER TEMPERATURE: DEGREES OR NONE

This specifies the minimum outdoor reset setpoint for the LL master. If the outdoor reset function calculates a temperature that is below the temperature specified here, then this parameter's temperature will be used. If this parameter is invalid or None then the outdoor reset function will be inhibited and will not run: if it is enabled then an alert is issued.

4.7.6DEMAND AND RATE

On/Off Hysteresis Includes hysteresis shifting at turn-on, turn-off

LLOFF HYSTERESIS: DEGREES OR NONE LL ON HYSTERESIS: DEGREES OR NONE

The LL hysteresis values apply to all setpoint sources. The behavior of the hysteresis function is identical to the behavior of the stand-alone CH hysteresis function, except:

•where stand-alone CH hysteresis uses the on/off status of a single burner, the LL hysteresis uses the on/off status of all slave burners: this status is true if any slave burner is on, and false only if all are off.

•where stand-alone CH hysteresis uses time of turn-on and turn-off of a single burner, the LL hysteresis uses the turn-on of the first slave burners and the turn-off of the last slave burner.

LEAD LAG PID

The behavior of the Lead Lag PID function is identical to the behavior of the stand-alone CH PID function. The same gain scalars and