Lochinvar 51 operation manual Boiler temperature regulation

Installation & Operation Manual

11 Operating information (continued)

Monitor external limits

Connections are provided on the connection board for external limits such as flow switch, low water cutoff, gas pressure switches, and a louver proving switch. The SMART SYSTEM will shut off the burner and inhibit relighting whenever any of these external limits open.

Run-time and alarm outputs

The boiler provides dry contacts for indicating when the boiler is running, and when it is unable to operate.

Run-time and cycle counting

The control uses two timers to monitor the total hours of burner operation. One timer monitors the time the boiler is firing in the Space Heating Mode. The other timer monitors the time the boiler is in the DHW Mode.

The control uses two (2) ignition counters to monitor the amount of boiler cycles. The first counter counts all ignitions of the control. The second counter counts only ignition attempts that have failed.

Service reminder

The control can be programmed for service reminder notification. This notification will become active when either a set time frame has expired, or a set amount of running hours or cycles has expired (all adjustable by the installer). The display will show a Maintenance Required screen. The service reminder notification can be reset or disabled by the installer.

The time dependent feature has been disabled by the manufacturer. To enable this feature change parameter K1 to the desired time range, reference the Knight Wall Mount Service Manual for details regarding parameters.

Error logging

The control will hold in memory the last 10 lockouts as well as the last 10 blockings. The date and time of the occurrence will be recorded as well. Only the 10 most current occurrences of each will be held in memory.

Boiler temperature regulation

Operating temperature (target)

The SMART SYSTEM control module senses water temperature and regulates boiler firing and firing rate to achieve a target temperature. The target temperature can be set between 32°F and 190°F.

•Target temperature is fixed when the outdoor sensor is not installed.

•Target temperature is calculated as described in this section under “Outdoor Reset Operation” and “Target Temperature Boost” when the outdoor sensor is connected.

High limit operations

The Knight wall mount is equipped with adjustable automatic reset and manual reset high limits. The automatic reset high limit has a maximum set point of 200°F and the manual reset high limit has a maximum set point of 210°F.

When the outlet temperature exceeds 200°F, the automatic high limit action occurs. The boiler shuts down until the outlet water temperature cools below 190°F, and a 60 second timer has expired. If the outlet temperature continues to increase, the manual reset high limit action will occur at 210°F.

High limit test procedure

NOTICE	Please note that the brackets ([]) denote
	screen status.

1.Turn ON the main power to the boiler by placing the ON/OFF switch in the ON position.

2.If boiler status reads [SHUTDOWN] place the boiler into the active position by pressing the RIGHT SELECT [ON] key.

3.Locate the pinhole (SERVICE button) below the RESET button on the display board. Insert a thin wire (such as a paper clip) into the hole and press the button once, hold for five (5) seconds to place the boiler into Service Mode. In Service Mode the boiler will fire at ignition speed and will then modulate up to full fire.

4.From the Status Screen, press the NAVIGATION dial to access the Set Points Screen.

5.Press the LEFT SELECT [LIMITS] key.

6.Select the manual reset high limit (MRHL) by pressing the NAVIGATION dial.

7.Decrease the set point of the MRHL below the outlet temperature by turning the NAVIGATION dial counterclockwise.

8.Press the RIGHT SELECT [SAVE] key.

9.Press the RIGHT SELECT [HOME] key.

10.The new parameters will upload to the control and the MRHL will function causing boiler shutdown and [LOCKOUT] to be displayed.

11.Press the RESET button to clear the lockout.

12.Repeat Steps 4, 5, and 6.

13.Set the MRHL to the appropriate set point by turning the NAVIGATION dial clockwise.

14.Repeat Steps 8 and 9.

Low water cutoff protection

1.The SMART SYSTEM control module uses temperature sensing of both supply and return areas of the heat exchanger. If the flow rate is too low or the outlet temperature too high, the control module modulates and shuts the boiler down. This ensures boiler shutdown in the event of low water or low flow conditions.

2.Some codes and jurisdiction may accept these integral features of the control in lieu of requiring an additional limit control or low water cutoff. Consult local jurisdiction to determine. A low water cutoff is available from the factory (WTR20009).

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