Software Release Note

Pump Changeover Module PCO3c1

General

This module based on the ACT DIN products is designed to work in conjunction with the SeaChange Boiler Controllers, Secondary circuit Controllers or any Zone level product which supports actuators. The module provides control of a pair of pumps.

Hardware

This version of code runs on the 0006/0003 issJ12   ACT DIN hardware., universal input scaling.

The code is contained in a 27C512 prom.

Registration

The module is registered to it's main controller by putting the main controller into config mode and then pressing the registration button on the PumpChangeover module. Registration is confirmed by the status LED on the module flashing once. One or two PCO modules can be used with each Boiler controller, see the relevant issue notes for the capabilties of other main controllers. The config variable TYPE needs to be set to match the application.

Functional Description

This module receives status information from the main controller. The command to run the pumps is determined by the TYPE config variable see table above. Note that the pumps can be run once ther is significant demand >5% or for the whole of the Occupied (or Optimum Start)  period regardless of whether demand exists.

This module provides control for pairs of pumps where automatic changeover on failure of a pump is required. The module has a relay output for each pump and two flow detection inputs. The flow condition must be indicated by shorting the input pins with a volt free contact. (sense can be changed by changing ALST)

On receipt of a command to run the pump, the pump which has been off longest will be started, if after the flow proving 'delay' (set by config variable DLAY, default 10 seconds) neither of the two inputs have been made then the first pump will be stopped and the other pump started. This condition is indicated by the top LED alternating red and green. If again no proof of flow is received then this is indicated by the top LED flashing red. The pump action for this failure mode is modified by the config variable FMDE, allowing both pumps to run(1), last one to run(2) or switch both off(3) dependant upon the requirements of the installation.

If a fan has failed then the third relay will be energised allowing connection to an annunciator.

The error condition is reset by the flow proving signal being reinstated or by the command signal being removed, i.e. it will start with no error at commencement of the next occupied period. The error condition can also be manually reset by pressing the 'Override' button.

During normal operation the top LED will be steady green, the lower status LED will show green if the controlling device 'is occupied'.

ChangeOver on Hours Run

The controller will automatically change the pumps over if the continous run time exceeds the setting of Maximum Hours Run MXHR. This is set to 24 by default.

Alarms

The module can generate networked Alarms for failure of either pump If both fans fail then the Boiler will generate a STOP alarm in addition to the alarms generated by the PCO module. The Boiler will shut down and will not restart until the override button has been pressed or the Boiler reset by clearing switch3 to zero.

Sensors and Plots

The run hours for each fan are available as sensor1 and sensor 2 and these are plotted for the last 96 days using the normal Doorway plots. The stored hours run for each fan can be reset using Switches 3 & 4. The maximum hours counted before roll over is 9999 hours.

TYPE parameter

The PCO module has a TYPE configuration variable, this must be set up , probably at the factory, to determine the conditions under which the Pumps will be run.

Configuration Parameters