(6) With the circuit board now activated, the power relays should turn on one at a time. If
they have not started to come on as yet, temporarily turn up the temperature on the
aquastat to the maximum setting, it should be returned to the normal setting when you
are finished troubleshooting. The power relays for controlling the elements should now
start to turn on. As each relay turns on, one “element relay indicator” light on the
control board should come on as well.
a) If the element relay indicator lights do not come on, disconnect the temperature
sensor by pulling out the connector at the control board (the one with the two gray
wires).
b) If the lights now come on the temperature sensor needs to be replaced. If they still
do not come on, short the two gray wires at the pump relay. If they come on then the
pump relay needs to be replaced.
c) If they still do not come on then the control board needs to be replaced.
d) If the element relay indicator lights come on, but the power relays do not come on
then the high limit control may be preventing them from coming on. This may be
due to a faulty component, or may be an actual temperature condition. A faulty high
limit control will prevent the “hi limit indicator” light from coming on.
(7) Temporarily (no more than one second) place a jumper wire across the two terminals on
the high limit control.
a) If the relays energize, replace the high limit control.
(8) If all the relays energize and there is no heat, then check for power to each of the
heating elements.
a) With all the relays energized, check that there is power to each of the elements with
a volt meter. If there is no voltage reading, replace the relay connected to that
element.
b) If there is power to the elements, but no heat, then with the all the power
disconnected to the boiler, check the resistance of each element with an ohm meter
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