RT-SVX25C-EN
37
Pre Start
Test Modes
There are three methods in which the “Test” mode can be cycled at LTB-Test 1 and LTB-Test 2.
1.
Step Test Mode - This method initiates the different components of the unit, one at a time, by
temporarily shorting across the two test terminals for two to three seconds.
For the initial start-up of the unit, this method allows the technician to cycle a component “On”
and have up to one hour to complete the check.
2. Resistance Test Mode - This method can be used for start-up providing a decade box for variable
resistance outputs is available. This method initiates the different components of the unit, one
at a time, when a specific resistance value is placed across the two test terminals. The unit will
remain in the specific test mode for approximately one hour even though the resistance is left
on the test terminals.
3. Auto Test Mode - This method is not recommended for start-up due to the short timing between
individual component steps. This method initiates the different components of the unit, one at
a time, when a jumper is installed across the test terminals. The unit will start the first test step
and change to the next step every 30 seconds. At the end of the test mode, control of the unit
will automatically revert to the applied "System" control method.
For unit test steps, test modes, and step resistance values to cycle the various components, refer
to
Table 6
.
Verifying Proper Air Flow
(Units with Belt Drive Indoor Fan)
Much of the systems performance and reliability is closely associated with, and dependent upon
having the proper airflow supplied both to the space that is being conditioned and across the
evaporator coil.
The indoor fan speed is changed by opening or closing the adjustable motor sheave.
Table 6.
Service test guide for component operation
TEST
STEP MODE
Fan
Econ
(a)
(a)
The exhaust fan will turn on anytime the economizer damper position is equal
Comp 1 Comp 2 Heat 1 Heat 2 Ohms
1
Fan
On
Minimum
Position
Setpoint
0%
Off
Off
Off
Off
2.2K
Minimum
Ventilation
On Selectable Off
Off
Off
Off
2
Economizer
Test Open
On Open Off Off Off Off 3.3K
3
Cool Stage 1
On
Minimum
Position
On
(b)
(b)
The condenser fans will operate any time a compressor is "On"
Off Off Off 4.7K
4
(c)
(c)
Steps for optional accessories and non-applicable modes in unit will be skipped.
Cool Stage 2
On
Minimum
Position
On
(d)
(d)
The condenser fans will operate any time a compressor is "On"
On
(e)
(e)
The condenser fans will operate any time a compressor is "On"
Off Off
6.8K
5
(f)
(f)
Steps for optional accessories and non-applicable modes in unit will be skipped.
Reheat On
Minimum On On Off Off 33K
6
(g)
(g)
Steps for optional accessories and non-applicable modes in unit will be skipped.
Heat Stage 1
On
Minimum
Off
Off
On
Off
10K
7
(h)
(h)
Steps for optional accessories and non-applicable modes in unit will be skipped.
HeatStage 2
On
Minimum
Off
Off
On
On
15K
