Testing And Troubleshooting - Tekmar Mixing Control 356 Manual

Testing the Control
The Mixing Control 356 has a built-in test routine which is used to test the main control functions. The 356 continually monitors the
sensors and displays an error message whenever a fault is found. See the following pages for a list of the 356's error messages and
possible causes. When the
output speed. Once the button is released, the output relays return to normal operation.
Troubleshooting
When troubleshooting any heating system, it is always a good idea to establish a set routine to follow. By following a consistent
routine, many hours of potential headaches can be avoided. Below is an example of a sequence that can be used when diagnosing or
troubleshooting problems in a hydronic heating system.
Establish the problem. Get as much information from the customer as possible about the problem. Is there
Establish the
too much heat, not enough heat, or no heat? Is the problem only in one particular zone or area of the building,
Problem
or does the problem affect the entire system? Is this a consistent problem or only intermittent? How long has
the problem existed for? This information is critical in correctly diagnosing the problem.
Understand the sequence of operation of the system. If a particular zone is not receiving enough heat, which
Understand the
pumps or valves in the system must operate in order to deliver heat to the affected zone? If the zone is
Sequence of
receiving too much heat, which pumps, valves, or check valves must operate in order to stop the delivery
Operation
of heat?
Sketch the Sketch the piping of the system. This is a relatively simple step that tends to be overlooked, however, it can
Piping in the
often save hours of time in troubleshooting a system. Note flow directions in the system paying close
System
attention to the location of pumps, check valves, pressure bypass valves, and mixing valves. Ensure correct
flow direction on all pumps. This is also a very useful step if additional assistance is required.
Document the control for future reference. Before making any adjustments to the control, note down all of
Document the
the items that the control is currently displaying. This includes items such as error messages, current
Control
temperatures and settings, and which devices should be operating as indicated by the LCD. This information
is an essential step if additional assistance is required to diagnose the problem.
Isolate the problem between the control and the system. Now that the sequence of operation is known and
Isolate the
the system is sketched, is the control operating the proper pumps and valves at the correct times? Is the
Problem
control receiving the correct signals from the system as to when it should be operating? Are the proper
items selected in the menus of the control for the device that is to be operated?
Test the contacts, voltages and sensors. Using a multimeter, ensure that the control is receiving adequate
Test the Contacts
voltage to the power terminals and the demand terminals as noted in the technical data. Use the multimeter
Voltages &
to determine if the internal contacts on the control are opening and closing correctly. Follow the instrutions
Sensors
in the Testing the Wiring section to simulate closed contacts on the terminal blocks as required. Test the
sensors and their wiring as described in the sensor Data Brochures.
Copyright © D 356 -05/00
button is pressed, the Boiler relay closes and the variable speed injection pump turns on to 100% of its
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