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Follow the testing method that best describes your installation
problem.
If the previous tests did not solve the issue, check that the
equipment is working.
The testing procedures require
a multimeter, also known as a
multitester or Volt-Ohm Meter
(VOM). Refer to the multimeter’s
instructions for operation.
This document contains testing procedures for the Common
Maker to determine installation errors and equipment faults.
Equipment:
Any furnace, boiler, zone controller, zone valves,
etc, the thermostat is controlling.
Thermostat Cable:
The cable in the wall that connects the
thermostat to the equipment. Contains two or more wires.
Thermostat Subbase:
The component attached to the wall
that the thermostat fits onto. Contains the connections to the
thermostat cable wires.
Open Circuit:
A break in a wire that prevents electricity from
flowing through it.
Short Circuit:
An unintended
connection between two or
more wires in the thermostat
cable, or between a wire and
electrical ground.
Common Terms
Overview
Needed Tools
Installation Testing
Equipment Testing
No Power at Thermostat
Common Maker Test
Equipment Will Not Start
Thermostat Cable Test
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The thermostat is not powering on
Determine if the Common Maker is faulty
The thermostat has power but the equipment will not start
Determine if the thermostat cable is damaged
Common Maker
Troubleshooting
Multimeter
00.0
Ω
V~
V
A
DIGITAL
MULTIMETER
A
C
B
D
