Troubleshooting Step By Step Procedure
The following is a step by step procedure to help in troubleshooting any problems with this
boiler. These steps should be performed only by qualified personnel with experience in
hydronic heating systems, and electrical heating equipment. You are working with high
voltages and should be extremely careful.
Before energizing boiler, ensure system is full of water.
(1) Make sure that there is power to the boiler. There must be power to the boiler to
complete these troubleshooting steps.
a) There should be power at the main terminal block. You should read 120 volts
between L1 and N, 120 volts between L2 and N, and 240 volts between L1 and L2.
b) Disconnect the thermostat wires from terminals T1 and T2. Measure the voltage at
the top of the boiler at each heating element. If you read voltage at any of the
elements, then the element relays for that element are stuck on and need to be
replaced.
c) Next measure the voltage from the N terminal of the main terminal block to each
terminal of each heating element. If you read voltage at any of the elements, then a
single element relay for that element is stuck on and needs to be replaced.
(2) Check the fuse.
a) Remove the fuse located inside the boiler. Check it for continuity. Replace with a
new fuse of the correct type if necessary.
b) Otherwise replace the existing fuse.
(3) Check that there is 24 volt AC power on the secondary side of the transformer. There
must be 24 volt AC power on the secondary side of the transformer for the boiler to
operate. If there is no power the transformer needs to be replaced. When there is 24 volt
power to the board the “Power On” light on the board should be on.
(4) With the thermostat wires still disconnected, connect a jumper wire from terminal T1 to
terminal T2. The “Thermostat On” light should now be on.
a) This should energize the pump relay to the right of the control board, you should
hear a click. If not check that there is 24 volt DC power on the two relay terminals
with purple wires.
b) If there is no power at the relay, the control board needs to be replaced.
c) If there is power, but the relay is not turning on, replace the relay.
(5) When the relay is energized, it will supply 120 volt power for running the pump.
a) There should now be 120 volt AC power to the terminals labeled PL and PN.
b) If there is no power, replace the relay.
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