Mercury PR0091 User Manual

 

Mercury 6-5 Stat – Installation & User Guide

 
Over-ride Operation 
 
The 5 Channel Thermostat can operate either from its internal channel time settings or from a network Data 
Manager GP Timer channel (P70 sets the mode either local or remote). If the 5 Channel Thermostat is set up 
to use the remote timing channels it reverts to local mode if network communications are lost for more than 5 
minutes. An over-ride occurs when a resistor is switched in across the input which has to be overridden, 
however when the over-ride signal is removed the channel returns too normal operation. 
 
 
 
Thermostat Over-ride: - 
 
 
When a channel is configured for thermostat operation the following will occur when an over-ride is present on 
the channel input. In the example below channel 1 is set as a thermostat in a heating application, the relay 
inverse feature is disabled, the controller timer is set to local operation and is off. When the timer is in the off 
period the channel will not be enabled for heating and the thermostat relay remains off, providing the probe 
temperature is not below the frost detect set point. As shown in the diagram an over-ride is applied to channel 
1, this will enable the channel. The thermostat relay does not immediately turn on, it only does so when the 
temperature drops below the cut-in set point. The controller will continue normal temperature control until the 
over-ride is removed or the next scheduled off occurs in the local timer schedule. When the timer is in the on 
period, the over-ride has no effect. Note:- An over-ride should be removed as soon as it is not required on an 
input. 
 
 
 
 
 
 
 

Cut-in Set

Point

Frost

Detect

Time

Relay

 State

On

Off

Over-ride

Activated

Thermostat Relay Status

Ch 1 Probe Temperature

Tempera

ture

Diff

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 

 
 
 

  

Revision 1.2 

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