Carlin 90524A User Manual
Front
Rear
(size reduced)
Easy-wire terminal strip
Microprocessor-operated
(Processor coordinates operation and diagnostic)
Easy remote sense
(Electronic sensor, wired to control)
Self-checking program
(Control locks out on diagnostic failure)
Diagnostic/status LED’s
(LED’s indicate power, call for heat, and lockout)
SMC technology on burner relay
(lockout when welded contact sensed)
Instructions
Functions
Carlin’s 90524A can be operated as either a triple limit control or a cold-start •
control, determined by the setting of the LOW LIMIT adjustment.
Triple limit operation (LOW LIMIT on): Provides adjustable high limit set-•
ting and maintains an adjustable minimum temperature in the boiler (low
limit setting) while in stand-by (no space heating call); used for tankless
heater applications. (See Figure 3 , page 4.)
Cold-start operation (LOW LIMIT off): Provides adjustable high limit set-•
ting and low temperature protection (delays circulator start until the boiler
is heated above the fixed minimum temperature setpoint); used to prevent
condensation in the boiler on cold start. (See Figure 4 , page 4.)
The 90524A provides input from zone controllers or relays (ZR contact) and •
output to enable circulators (C1 contact) or zone controllers (ZC contact).
The gas valve/burner output is on the B1 terminal. Call for heat input is on
the T-T terminals.
Specifications
Carlin’s Model 90524A microprocessor-operated temperature controls are •
described below.
Refer to separate product listing sheets for pre-defined models, or request •
a control to meet your specifications, within the available ranges listed
below.
Model 90524A
Input power (L1-L2) 120 VAC, 10 VA, 60 Hz
Control power (T-T) 24 VAC, 130 mA
High limit range Adjustable
High limit differential Adjustable (fixed if low limit is used or if
Low limit range Adjustable with OFF position
Low limit differential Adjustable (fixed if differential setpoint is
Low temp function
Low temp differential
Temperature ranges
Setting —
Differential —
Contact ratings
Full load
Locked rotor
Ambient temperature +32°F to +140°F (0°C to +60°C)
Storage temperature -40°F to +185°F (-40°C to +85°C)
Agencies UL Listed US and Canada
Te c h s u p p o r t 800-989-2275
differential setpoint is OFF)
OFF)
Fixed
Fixed
Any value/range between 50° & 250°
Any value/range between 5°F and 100°F
Burner, circulator and ZC contacts
120 VAC, 10 amps (total current on all
contacts not to exceed 16 amps)
120 VAC, 60 amps (total current on all
contacts not to exceed 96 amps)
carlincombustion.com
Model 90524A Triple limit or cold-start control — Instructions
Where appliance instructions differ from this manual, follow the appliance instructions.
90524A componentsFigure 1
1
2
3
Front
1 Green LED — POWER ON (Lockout, see
page 3)
2 Amber LED — CIRCULATOR ON
3 Amber LED — BURNER ON
4 Thermostat T-T input terminals
5 Terminal strip (back of control)
6 Sensor terminal strip (quick-release style)
7 Differential adjustment (adjusts High Limit
differential when in cold-start operation;
adjusts Low Limit differential when in triple
limit operation) — when in OFF position,
default high and low limit differentials are
used
8
9
10
6
5
4
8 Hidden reset button
9 Low limit adjustment (set to OFF for cold-
start operation)
10 High limit setpoint adjustment
Rear
7
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Carlin part number MN90524AM Rev. 01/19/09
Model 90524A Triple limit or cold-start control — Instructions
Where appliance instructions differ from this manual, follow the appliance instructions.
Configurations
Control kits — 90524A controls mount to a standard 4x4 J-box, supplied •
with the control. Mount the box directly to a well (new or existing) with
hardware supplied, or panel mount. See Figure 2 for dimensions.
Well kits — Wells for 90524A sensors are available in the sizes shown •
in Figure 2. Well kits include sensor mounting hardware designed to
hold sensor securely in position.
Sensors — Sensors are available in single configurations.•
Mounting the 90524AFigure 2
Model 90524A diagnostic LED’s
90524A controls have three LED’s, as explained below. See following pages for operating
sequence and LED behavior.
Left LED
POWER ON
green
The LED’s can be off, on or flashing. The symbols below are used in this manual to show
the state of these LED’s during operation of the control.
Green LED
Amber LED’s
[
LED status Indicates the following:
With no power applied, the thermostat (TT) circuit and all output con-
Power OFF
Power ON
[
Soft lockout
Hard lockout
Latchup
tacts are de-energized. All LED’s are off.
When power is applied to the L1/L2 terminals, the thermostat circuit is
energized. Voltage (24 VAC) is applied to the thermostat terminals. The
90524A starts a self test to check the sensor and the microprocessor,
and to verify that the limit contacts are open. The 90524A becomes
fully operational after this 2-second self test.
Green LED flashing once per second, burner LED off, B1 contact open,
and circulator LED on or off — occurs if control senses internal failure
or sensor problem (open or shorted sensor).
The control will revert to normal operation if the problem is corrected
within 15 seconds. Otherwise, the control enters hard lockout. See
“Fault log” information below.
Green LED flashing twice per second, burner LED off and B1 contacts
open, circulator LED on and circulator contacts closed — occurs when
burner contact is sensed closed, and does not clear after two attempts
or soft lockout has timed out.
Reset by cycling power off/on.
Green LED off, burner LED off, B1 contact open, circulator LED on, and
ZC and C1 contacts closed — occurs when burner contact is sensed
closed, and does not clear after three attempts.
Not resettable — requires control replacement.
Center LED
CIRCULATOR ON
amber amber
OFF – ON Power on
FLASH Slowly (once per second) Soft lockout
FLASH Rapidly (twice per second) Hard lockout
OFF – ON Burner on or Circulators powered
Indicates the LED in this position can be either on or off.
Right LED
BURNER ON
Definitions
High limit Shut-off temperature during space heating (call for heat at
T-T or ZR).
Setpoint is adjustable at lower front center of control.•
Differential is fixed when in triple limit operation (LOW •
LIMIT on).
Differential is adjustable on back of control when in cold •
start operation (LOW LIMIT set to OFF).
Low limit Temperature maintained during stand-by (no call for heat
at T-T or ZR) when in triple limit operation (LOW LIMIT on).
The setpoint for the low limit (minimum temperature in •
the boiler during standby) is adjustable with the lower
left adjustment.
The differential for low limit is adjustable with the adjust-•
ment on the back of the control.
The circulator output at C1 is activated only when •
the temperature in the boiler is above the low limit
setting.
Low temp Boiler condensation protection setting when in cold-start
operation (LOW LIMIT set to OFF).
This setting is fixed.•
The differential is fixed.•
The circulator outputs are disabled until the boiler tem-•
perature rises above the low temp setting.
Carlin part number MN90524AM Rev. 01/19/09
Fault
log
Sensor open
Sensor shorted
90524A controls self monitor, and can indicate fault conditions with
the LED’s.
Fault conditions are recorded in the retrievable fault log. Two conditions, caused by sensor detection problems, are shown below. Other
LED conditions displayed in the fault log are related to internal control
problems. Reset the control as explained above. Controls in latchup
cannot be reset. They must be replaced.
To access the fault log, press the hidden reset button (located left of
the LOW LIMIT adjustment on the front of the control). Hold for one
second or longer. All three LED’s will come on for 1 second, then go off
for 1 second. If any error codes have been logged since the last error
code display, the LED’s will flash a pattern four times for each error
code, then proceed to the next. After all codes have been shown, the
error code log will automatically clear.
For applications that might encounter unexplainable control outages,
contact Carlin Technical Support for instructions to access the fault log
and interpret the results.
Sensor OPEN fault code.
The sensor is detected OPEN (resistance more than 60 Kohms).
Sensor SHORTED fault code.
The sensor is detected SHORTED (resistance less than 300 ohms).
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