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P/N 42-9472 Copyright 2008 Mestek, Inc.
Cast iron condensing boiler
Cast iron condensing boiler
— Control manual
Troubleshooting
(continued)
5
Situtation
Suggested procedure
Nothing happens when the
power switch is turned on.
Check 120VAC power to connection board. Verify power is connected per wiring diagrams.
Th e Power switch light (ON -Position) should illuminate if power is wired correctly.
If the Ignition Control is active, but the front panel display is inactive check:
Cable and cable polarity from the control board to the display.
Check for 120vac on the primary of the transformer and 24vac on the secondary. If one of the 24vac
interlocks has been shorted to ground or the 24vac output is low, the transformer may be damaged or
a 24vac circuit may be miswired.
Th e 200i control is equipped with resett able fuses on the power input circuit. Wiring power incorrectly
to the unit will cause these fuses to open. Once the incorrect wiring is corrected, the fuses should reset
themselves in less than 5 minutes.
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The display shows combustion
air damper failure.
If you are not using the combustion air damper then it needs to be disabled in the AUX FUNCTIONS menu.
Th e prove switch for the combustion air damper is not closing. Check to make sure the dampers are being
controlled by the output relay you specifi ed when programming for the damper. Also check to make sure
the prove switch is working properly.
If there is no proving switch, you must put a jumper wire across input connection (USER INTRLK).
If these steps have been done and you continue to get the error message, check the sensor TYPE specifi ed
in the SENSORS menu. If it is set to NONE, the controller will not recognize the closed circuit. Set the
Sensor type to ON/OFF.
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The display is displaying random
characters or the control keeps
resetting.
Th ere may exist a grounding problem with the controller or one of the boilers, pumps, contactors or other
devices connected to it.
If all grounding is correct, there may be an issue with radiated or induced electrical noise (interference).
Th is may be caused by arcing across a contactor’s contacts when starting a pump motor or a large electrical
load. It may also be caused by the ignition transformer being improperly grounded or the spark gap being
out of adjustment.
Att empt to identify the noise source:
What is the boiler/controller trying to do at the time of the failure?
Is the boiler on the same circuit as the noise source? (Th e boiler should have isolated power.)
Are shielded sensor wires used? (Ensure the shields are grounded only at the boiler control end.)
Are any sensors or sensor wires located near a transmitt ing antenna? (Move sensor)
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There are no heating boilers on.
Check the sett ings for OA SETPOINT and OA RESET.
If the outdoor air temperature is above the OA SETPOINT and OA RESET is on, the circulator pump
relay will be locked out and the heating boilers will not fi re.
If the water temperature is within the heating band around the setpoint, boilers will not come on.
Th e water temperature must fall below the lower band limit to begin fi ring boilers.
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Unable to change the # of Boilers
in the BOILERS menu.
In H-Net method, the 200i control auto-detects the boilers in the system and adjusts the number of boilers
accordingly.
Using H-NET, if the numbere of boilers is not being detected properly as the actual number of boilers in
the system, check each boiler. Th
ere can only be (1) master boiler, but there can be up to 15 member boilers.
Make sure only the master boiler has a Header Sensor connected.
Verify that each boiler’s SmartCycle cable is in place.
Verify that each boiler has a unique address assigned (ADVANCED SETUP, DISTRIB CTRL, LOCAL AD).
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The BOILERS menu only indicates
one boiler, but there are member
boilers connected. The amber
light blinks on all of the boilers
communication’s jacks.
Verify that the latest version of fi rmware is installed on all boilers.
All boilers in a system must have the same fi rmware revision (version).
Verify the proper termination is set on the Master and the last Member boiler.
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