Warning – LAARS M4-LHS - Installation Manual User Manual

Page 35

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HT# 059295-00

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M4-LHS installation and Operation Manual

35

Avoiding Conflicting Boiler Limits

The temperature limits set on the boilers MUST be set considerably higher than the M4-LHS's

Set Point for the reasons detailed below.

• The M4-LHS sensor is located in a common header some distance from the boilers.

• As the temperature rises in the header and before reaching the sensor location, energy is

dissipated. Therefore, the temperature in the header could be lower than that registered by

boiler sensors.

• In addition to the normal drop experienced between the boiler’s temperature and that

read by the M4-LHS sensor, the Last Stage Hold setting must be accounted for. The boiler

limit must be set above the Set Point PLUS the Last Stage Hold PLUS the normal drop

experienced in the piping.

• Using the previous example of a 10°F Last Stage Hold with a 160°F Set Point, the boilers’

limits must be set enough over 170°F to prevent the boilers’ internal limits being reached.

In this situation, the boiler high limit should be set higher than 180°F to prevent erratic

operation.

WarNiNg

The temperature limits set on the

boilers must be higher than the

M4-LHS Max Water Temp. Read

the left section for details that will

prevent erratic system operation.

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