tekmar 664 Snow Detector & Melting Control Installation - Manual (Page 30)

30 of 36 © 2009 D 664 - 07/09
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
Understanding
the Sequence of
Operation
Use the Test
Routine
Sketch the
Piping in the
System
Troubleshooting
Document the
Control
Isolate the
Problem
Test the Contacts,
Voltages and
Sensors
Monitor the
System
Establish the problem. Get as much information from the customer as possible about the problem. Is there
too much heat, not enough heat, or no heat? Is the problem only in one particular zone or area of the building
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 pumps or valves in the system must operate in order to deliver heat to the affected zone? If the zone
is receiving too much heat, which pumps, valves or check valves must operate in order to stop the delivery
of heat?
Press the Test button on the control and follow the control through the test sequence as described in the
Testing section. Pause the control as necessary to ensure that the correct device is operating as it should.
Sketch the piping of the system. This is a relatively simple step that tends to be overlooked, however it can often
save hours of time in troubleshooting a system. Note flow directions in the system paying close 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 the items that the control is currently displaying. This includes items such as error messages, current
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
the system is sketched, is the control operating the proper pumps and valves at the correct times? Is the
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
voltage to the power terminals and the demand terminals as noted in the technical data. Use the multimeter
to determine if the internal contacts on the control are opening and closing correctly. Follow the instructions
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.
Monitor the system over a period of time. Select the applicable items in the MONITOR menu of the control
and reset them to zero. Allow the system and the control to operate over a known period of time and then
record the Monitor items. Use this information to help diagnose any remaining problems.