25
Simultaneous Heat and Cool Failure
1. Emergency Stop is activated.
Method 2
The second method for determining system status is done by
checking voltage readings at the RTRM (J6). The system
indication descriptions and the approximate voltages are listed
below.
System Failure
Measure the voltage between terminals J6-9 & J6-6.
Normal Operation = approximately 32 VDC
System Failure = less than 1 VDC, approximately 0.75 VDC
Test Mode = voltage alternates between 32 VDC & 0.75 VDC
Heat Failure
Measure the voltage between terminals J6-7 & J6-6.
Heat Operating = approximately 32 VDC
Heat Off = less than 1 VDC, approximately 0.75 VDC
Heating Failure = voltage alternates between 32 VDC & 0.75
VDC
Cool Failure
Measure the voltage between terminals J6-8 & J6-6.
Cool Operating = approximately 32 VDC
Cool Off = less than 1 VDC, approximately 0.75 VDC
Cooling Failure = voltage alternates between 32 VDC & 0.75
VDC
To use LED’s for quick status information at the unit, purchase
a BAYSENS010B ZSM and connect wires with alligator
clamps to terminals 6 through 10. Connected each respective
terminal wire (6 through 10) from the Zone Sensor to the unit
J6 terminals 6 through 10.
Note: If the system is equipped with a programmable zone
sensor, (BAYSENS019A, or BAYSENS023A), the LED indicators
will not function while the BAYSENS010A is connected.
Resetting Cooling and Heating Lockouts
Cooling Failures and Heating Lockouts are reset in an identical
manner. Method 1 explains resetting the system from the
space; Method 2 explains resetting the system at the unit.
Note: Before resetting Cooling Failures and Heating Lockouts
check the Failure Status Diagnostics by the methods
previously explained. Diagnostics will be lost when the power
to the unit is disconnected.
Method 1
To reset the system from the space, turn the
MODE
selection
switch at the zone sensor to the
OFF
position. After approxi-
mately 30 seconds, turn the
MODE
selection switch to the
desired mode, i.e.
HEAT
,
COOL
, or
AUTO
.
Method 2
To reset the system at the unit, cycle the unit power by turning
the disconnect switch
“Off”
and then
“On”
.
Lockouts can be cleared through the building management
system. Refer to the building management system instructions
for more information.
Zone Temperature Sensor (ZTS) Service Indicator
The ZSM SERVICE LED is a generic indicator that will signal
the closing of a Normally Open switch at any time, providing
the Indoor Motor (IDM) is operating. This indicator is usually
used to indicate an airside fan failure.
The RTRM will ignore the closing of this Normally Open switch
for 2 (±1) minutes. This helps prevent nuisance SERVICE LED
indications.
Temperature Tests
Note: These procedures are not for programmable or digital
models and are conducted with the Zone Sensor Module
electrically removed from the system.
Test 1 - Zone Temperature Thermistor (ZTEMP)
This component can be tested by measuring the resistance
between terminals 1 and 2 on the Zone Temperature Sensor.
Below are some typical indoor temperatures, and correspond-
ing resistive values.
Zone Temperature
Nominal Resistance
50
°
F or 10.0
°
C
19.9 Kohms
55
°
F or 12.8
°
C
17.47 Kohms
60
°
F or 15.6
°
C
15.3 Kohms
65
°
F or 18.3
°
C
13.49 Kohms
70
°
F or 21.1
°
C
11.9 Kohms
75
°
F or 23.9
°
C
10.50 Kohms
80
°
F or 26.7
°
C
9.3 Kohms
85
°
F or 29.4
°
C
8.25 Kohms
90
°
F or 32.2
°
C
7.3 Kohms
Test 2 - Cooling Set Point (CSP) and Heating Set Point
(HSP)
Cool SP = Terminals 2 and 3
Range = 100 to 900 Ohms approximate
Heat SP = Terminals 2 and 5
Range = 100 to 900 Ohms approximate
Test 3
System Mode and Fan Selection
The combined resistance of the Mode selection switch and the
Fan selection switch can be measured between terminals 2
and 4 on the Zone Sensor. The possible switch combinations
are listed below with their corresponding resistance values.
Trouble Shooting
ReliaTel
TM
Controls
Содержание TTA075AD series
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