Lochinvar 3.5, 2.5 service manual Boiler temperature regulation, Outdoor reset operation, if used

10 Operating information

Monitor external limits

Connections are provided on the connection board for external limits such as an additional high limit. The SMART TOUCH control 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 four timers to monitor the total hours of

burner operation:
75	- 100%	50 - 75%
25	- 50%	<25%

The control uses four (4) 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. The third and fourth counters are the same as the first and second respectively, but can be reset by the installer.

Service reminder

The control can be programmed for service reminder notification. This notification will become active when either a set amount of time has expired, or a set amount of running hours or cycles has expired (all adjustable by the installer). The service reminder notification can be reset by the installer. The service company’s name and phone number can be programmed to display when service is due.

Error logging

The control will hold in memory the last 10 blocking faults as well as the last 10 lockout faults. The date and time of the occurrence will be recorded as well. Only the 10 most recent occurrences will be held in memory.

Boiler temperature regulation

Operating temperature (target)

The SMART TOUCH 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 (0°C) and 185°F (85°C).

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

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

Installation & Operation Manual

High limit operations

The Crest SMART TOUCH control has two (2) integral limits, one auto reset and one manual reset. The Crest also has one auxiliary manual reset high limit. The integral and auxiliary high limits are UL353 certified.

When the outlet temperature exceeds 195°F (90.6°C) (Installer Adjustable Parameter), integral auto reset high limit action occurs. The boiler will shut down until the outlet water cools down and the timer expires.

If the outlet temperature exceeds 200°F (93.3°C) (User Adjustable Dial), auxiliary manual reset high limit action occurs. The boiler will shut down until the outlet water cools down and the boiler is reset through the user interface.

If the outlet temperature exceeds 205°F (93.3°C) (Installer Adjustable Parameter), integral manual reset high limit action occurs. The boiler will shut down until the outlet water cools down and the boiler is reset through the user interface.

Low water cutoff protection

A low water cutoff device with test and reset functionality is provided in the boiler as standard equipment.

Flow sensing device

The SMART TOUCH control module uses temperature sensing of both supply and return temperatures of the heat exchanger. If the flow rate is too low or the outlet temperatures too high, the control module modulates down and will shut the boiler off. This ensures boiler shutdown in the event of low flow conditions.

NOTICE	If a mechanical flow switch is required to
	meet local code requirements the Crest
	boiler can be equipped with a field supplied
	outlet switch. Please reference page 38 of
	this manual for more information.

Outdoor reset operation, if used

Target temperature with outdoor reset

This feature improves the system’s efficiency as the outdoor temperature warms up.

See the Crest Service Manual to change the settings.

Reset curve

The reset curve looks at outdoor air temperature and adjusts the set point.

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