INSTALLATION, OPERATION, & MAINTENANCE MANUAL
IOM-764T
12/13
MODEL 764T
PNEUMATIC TEMPERATURE CONTROLLERS
SECTION I
I. DESCRIPTION AND SCOPE
The Model 764T is a temperature controller with an integral, rigid insertion bulb used for sensing temperature, and
outputting a pneu mat ic signal proportional to the deviation from the setpoint.
This IOM-764T does not cover use of oxygen as the "instrument air" fl uid. Such an application is outside the scope
of this IOM.
With proper materials and pipe sizes, the 764T can be used to measure the tem per a ture of liquid, gaseous, or va por
service. The installation of the thermal bulb can be direct or in di rect using a thermal well. Refer to Technical Bulletin
764T-TB for de sign and selection rec om men da tions.
Abbreviations Utilized:
IAS - Instrument Air Supply ES - Electrical Supply CW - Clockwise
SIG - Signal TC - Temperature Control valve CCW - Counter Clockwise
P/P - Pneumatic-to-Pneumatic P1 - Inlet Pressure REV - Revolution or Reverse
TC - Temperature Controller P2 - Outlet Pressure DIR - Direct
TI - Temperature Indicator TR - Condensate Trap FS - Flow Switch
SRV - Safety Relief Valve PB - Proportional band SOV - Solenoid Valve
II. INSTALLATION
1.
a.
b.
c.
d.
e.
Location of the thermal bulb into the medium
being con trolled is crit i cal.
Always insert the maximum bulb length into
the medium.
Always locate the bulb at a point downstream
of a heat exchanger to assure a near-equal
dis tri bu tion of the tem per a ture across the containment cross-section.
Always locate the control valve doing the tem per a ture control no further than 6-10 feet (2-3
meters) away from the controller when the
control valve does not have a po si tion er.
Do not use a thermal well unless the Owner's
process conditions, safety considerations or
main te nance pro ce dures require such; a ther mal
well enters an extra time response delay (i.e.
reduction in sensitivity) to the closed loop.
If a thermal well is required,to maximize heat
transfer effi ciency, locate on the top of a pipe
(vertical or at a 45° angle), duct, or at a 45°
SECTION II
f.
Figure 1: Typical Direct Cooling Application
angle to a vertical wall or horizontal top, when
possible, to allow fi lling of "void space" in well
with a suitable liquid heat transfer medium.
(See Figure's 4 and 5).
If a thermal well must be installed in a hor i zon tal
ori en ta tion, attempt to "pack" the "void space"
with steel or SST wool at bulb in ser tion. Use of
the well packing will in crease thermal effi ciency
(re duce time con stants) above that of a "dead
air" space in the "void space"; i.e. dead air space
acts as an "in su la tor" to heat transfer.
g.
Indoors, controllers without a thermal well
may be oriented in any position.
6.
Use suitable pipe thread sealant when in stall ing a
ther mal well or a 764T thermal bulb.
h.
i
j.
2.
The name plate of a 764T only indicates the
rotation to change temperature setpoint. It is rec om mend ed that a thermometer be in stalled very
near the location of the 764T. If the 764T utilizes
a thermal well, then the ther mom e ter should also
use a thermal well. If the 764T does not use a
thermal well, then the ther mom e ter should not
use a thermal well.
Outdoors, controllers without a thermal well
should be mounted with the main longitudinal
axis horizontal or be low. Make sure that the
vent port (either A or B) will not take in rain wa ter; use an angle fi tting, if necessary.
Indoors, controllers with a thermal well should
be mounted as recommended in Article 1.e.
Outdoors, controllers with a thermal well
should be mount ed at a 45° angle to main
pipe or duct axis, when possible. Make sure
that the vent port (either A or B) will not take
in rainwater; use an angle fi tting if necessary.
The con trol ler can be installed at any angle
below 45° at reduced ther mal sensitivity.
CAUTION: When engaging the threaded bulb con nec tion into its coupling or thermal well, DO NO
GRASP THE PNEUMATIC HOUSING OR KNURLED
LOCK NUT AND MANUALLY RO TATE THE CON TROL LER; ONLY USE A WRENCH (1-3/8") AND
TIGHT EN AT THE HEX SUR FACE PRO VID ED!
! Failure to comply may cause the factory-set cali-
bration to be al tered, re quir ing shop re-calibration.
Ro tate the unit CW (viewed from housing end) to
engage threads.
7.
Clean the pip ing and tub ing of all for eign ma te ri als
in clud ing chips, burrs, dirt, etc. prior to use. Use care
in ap ply ing thread seal ant or TFE tape to pre vent
ex cess ma te ri al from en ter ing the fl ow path.
3.
Recommended pipe tap size is 1/2" NPT for a
thermal bulb without a thermal well.
4.
Recommended pipe tap size is 3/4" NPT for a
thermal bulb with a thermal well.
5.
If the pipe tap size is greater than the size required
by either the thermal bulb or thermal well, a pipe
bushing fi tting is recommended rather than bell
reducers to bring the tap size to that required.
Figure 2: Typical Indirect Heating Application
Figure 3: Alternating Heating?Cooling System with
Split-Range Pneumatic (P/P) Positioners "Fail" to Cooling Mode on Loss of Air Supply
8.
KEEP CANTILEVERED PIPE, AIRSET, OR OTH ER
AP PUR TE NANC ES TO A MIN I MUM. It is recommended that the airset supplying in stru ment air be
independently mount ed elsewhere and tubed to the
con trol ler. Failure to comply with this rec om men da tion
may result in the even tu al loosening of the housing
from the thermal bulb, causing the unit to go out of
calibration.
9.
Connect piping/tubing per Tables 1 and 2. Do not
plug or restrict the open (unused) port (A or B) vent
connection. Port "A", Port "B" and "OUT PUT" are
identifi ed on the housing cast ing.
10.
764T's can operate with a lubricated, non-dried air
supply; however, good practice and other system
components (airsets, po si tion ers, relays, etc.) re quire
the use of the highest quality air supply available; i.e.
non-lu bri cat ed compressed air source and desiccant
dried air.
2
IOM- 764T
TEMPERATURE
11.
Instrument air exposed to outdoor freezing tem per a tures must be desiccant dried. Re frig er at ed
drying is not ad e quate.
12.
Instrument air exposed to indoors and/or no-freezing
tem per a tures is recommended to be re frig er ant
dried as a minimum.
13.
If the air supply is at a remote location, and can
not be practically dried and bears oil (i.e. plant air),
co a lesc ing fi lters must be utilized to re move as
much oil and water as possible, as well as par ti cles
over 15 mi crons size.
TABLE 1
Controller Model 764T
ISA to
Port
A Exhaust Supply
B Supply Exhaust
PROCESS
Direct Reverse
Increase in
temperature
increases output
signal
Action
Increase in
temperature
decreases output
signal
TABLE 2
Controller "Heating Applications"
IAS to
Port
A
B
B
A
Control Valve Controller
ATO-FC
(Reverse)
ATC-FO
(Direct)
ATO-FC
(Reverse)
ATC-FO
(Direct)
Actions
Reverse
Increase in temperature
decreases output signal.
Valve "fails" to "cooler"
process temperature.
Direct
Increase in temperature
increases output signal.
Valve "fails" to "hotter"
process temperature.
"Cooling" Applications
Actions
Direct
Decrease in temperature
decreases output signal.
Valve "fails" to "hotter"
process temperature.
Reverse
Decrease in temperature
increases output signal.
Valve "fails" to "cooler"
process temperature.
IOM-764T
Figure 4: Recommended Thermal Well (Opt. 64) Installation
3
FOR IN SER TION
INTO PIPE PEPENDICULAR TO CENTERLINE OF PIPE,
PIPE SIZE MUST
BE 8" (DN 200) OR
LARG ER, WITH
OR WITH OUT A
THERMAL WELL.
Ø
1
Ø
2
Nipple Length
L
2
Inch (DN) Inch (DN) Inch (mm)
1/2" 15 1" 25 6" (152)
3/4" 20 1-1/4" 32 6" (152)
1" 25 1-1/4" 32 6" (152)
1-1/4" 32 1-1/2" 40 6" (152)
1-1/2" 40 2" 50 6" (152)
2" 50 2" 50 NR
2-1/2" 65 2-1/2" 65 NR
NR = Not Required
Figure 5: Recommended Thermal Well (Opt. 64) Installation
Figure 6: High Temperature Thermal Bulb (Opt. 63)
4
IOM- 764T
PRINCIPLE OF OPERATION
III.
SEC TION III
1.
2.
3.
The 764T controller employs laminar fl ow to
de vel op the 3-15 psig (nominal 0.2 - 1.0 Barg)
output sig nal. Lam i nar fl ow was chosen because
it eliminates the need for range springs, levers,
pivots and other parts that pro duce friction and
lost motion.
A bimetallic thermal bulb is used to measure
tem per a ture. It is immersed in the fl uid whose
tem per a ture is to be controlled. A temperature
variation changes the length of the outer tube
more than it changes the length of the Invar rod.
This difference produces a minut movement of
the end of the Invar rod that contacts the sensor
plate. The sensor plate, in turn, throttles the fl ow
of instrument air through the sensor to develop
the 3-15 psig (0.2 - 1.0 Barg) output signal.
On direct acting controllers, see Figure 7, the
supply enters PORT B. With an increase in the
4.
5.
6.
sensed tem per a ture the supply air fl owing through
the sensor orifi ce in creas es, which elevates the
output signal. The pro por tion al band restriction
regulators the fl ow of ex haust through PORT A.
On reverse acting controllers the supply enters
PORT A and passes through the proportional
band re stric tion. With an increase in the sensed
tem per a ture the fl ow through the sensor or i fi ce
is increased, which reduces the output signal.
PORT B is the exhaust port.
Closing the proportional band adjusting screw
reduces the proportional band. Opening the screw
increases the proportional band.
The setpoint adjustment moves the sensor closer
to, or further away from, the sensor plate to change
the controlled temperature. Rotate clockwise
to increase temperature set point and counterclockwise to decrease temperature set point.
IOM-764T
Figure 7: 764T Direct Action View Shows Port A & B
Rotated From Actual Position
5
START-UP
IV.
1.
2.
3.
4.
5.
SECTION IV
Prior to pressurizing thru the airset, disconnect the
IAS at the airset inlet, open the IAS block valve
and air-blow the supply piping/tubing to clear of
any debris, moisture, etc. Re-connect to the airset.
Disconnect IAS tubing at the 764T, open the IAS
block valve at the airset and air-blow. Repeat for
IAS to the positioner, if supplied.
Set airset to 18 psig (1.24 Barg) outlet pressure.
Blow down the airset dripwell.
Establish fl ow past the bulb, allowing the bulb to
"sense" the actual temperature.
It is recommended that the control valve that
receives the output SIG of the 764T be manually
isolated at "cold" start-up. To prevent initial tem per a ture overshoot/undershoot while the sys tem
reaches thermal stability, initiate fl ow in the control
valve loop by manually bypassing.
NOTE: The PB and setpoint adjustments are
"interacting", meaning that to change one will likely
cause the other to have to be changed. With each
of these ad just ments, the temperature indicated
on the thermometer and the amount of rotation of
the adjusting screw (2.3) may be growing apart,
although the actual set point may not be changing. [If this setpoint deviation is objectionable,
determine the de vi a tion after all the ad just ments
have been com plet ed on the 764T.
NOTE: The 764T is shipped with the proportional
band (PB) set at a minimum value of ap prox i mate ly
3%. Match marks are factory placed on the hous ing (1) and needle valve (3) head cor re spond ing
to the 3% PB value.
CAUTION
Do not rotate the needle valve (3) CW below the 3%
PB value, as the unit will be rendered inoperative.
6.
7.
8.
Observe actual temperature of the fl uid being
temperature controlled utilizing a separate ther mom e ter instrument. As the control tem per a ture
approaches the "setpoint" temperature, be gin to
manually close the control valve bypass. At tempt
to establish steady-state manual control. NOTE: It
may take a time frame of 15 minutes or greater to
establish any level of steady-state man u al con trol;
DO NOT MOVE TOO FAST!
Observe the action of the control valve in re sponse
to the action of the 764T temperature controller.
Confi rm that the proper combined "loop action" is
occurring. If not correct, review the required action
desired, and reverse action of either the control
valve or 764T. To reverse action of a 764T, the
IAS to the 764T must be removed from the "as
installed" 764T port, and re-connect in reverse; i.e.
if IAS was installed to Port "B", change to Port "A",
and vice versa. (See Tables 1 and 2).
NOTE: The 764T is factory calibrated to ap prox i mate ly mid-range; i.e. a 50-220°F (10-104°C) temperature range will have setpoint at ap prox i mate ly
135°F (57°C). It is recommended that the unit be
shop calibrated, if required. Field calibration is, in
most cases, not practical. See Section VI.
Adjust setpoint by rotating the adjusting screw
(2.3) until the desired temperature is indicated on
the thermoneter.
Set Point
Adjustment
Porportional band
Adjustment
Min Porportional band
Alignment Mark
9.
Rotate needle valve (3) CCW approximately 1/4
of a full revolution; this corresponds to ap prox i mate ly 6% PB.
NOTE: The needle valve (3) may be adjusted
only 1-1/2 revolutions CCW from the initial 3%
PB min i mum value until the maximum 20% PB is
reached. Do not rotate needle valve (3) beyond
the 1-1/2" revolution limit.
3
1/4" NPT
Outlet Conn.
Figure 8: Front View
Output Gauge
Temperature Dial
1/4" NPT
"B" Conn.
1/4" NPT
"A" Conn.
6
IOM- 764T
10.
By observing the output SIG of the 764T as indicated on instrument gage (11), and manually
varying control valve bypass fl ow upwards and
downwards, the setpoint can be confi rmed as ap-
proximately the point where output SIG pres sure
is at 9 psig (0.62 Barg).
11.
Increase or decrease 764T setpoint to drive the
control valve closed. Remember the ∆T change
adjusted.
12.
Open the block valves isolating the control valve.
13.
Begin to manually close the control valve bypass
valve while simultaneously changing the 764T
setpoint back towards the desired setpoint prior to
Article 11, this sec tion. Attempt to simultaneously
change the setpoint and further close the bypass
in pro por tion al increments; i.e. close the bypass
about 10% while changing the setpoint by about
10% of the ∆T change of Article 11.
NOTE: Many temperature control system loops
have sizeable time constants; i.e. fl ywheel effect.
Make ad just ments in small increments and wait
for the results to stabilize.
If the control valve and 764T becomes unstable,
14.
leave the setpoint adjustment as is and increase
PB adjustment by rotating needle valve (3) ap prox i mate ly 1/8 revolution CCW. Wait for results
to sta bi lize.
Continue Articles 13. and 14. slowly until the control
15.
valve bypass valve is fully closed, and the 764T
controller is regulating fl ow.
16.
It is recommended that an "upset" be imposed
onto the system, and observe the capability of the
controller to stabilize the upset. If instability re sults,
PB should be increased in 1/8 CCW rev o lu tions
until stability is within the 764T's capability.
V.
MAINTENANCE
General:
A.
1.
2.
3.
4.
5.
Refer to Figure 10 for cutaway view of 764T
tem per a ture controller and Figure 6 for cut away view of the high temperature thermal
bulb with extension post (Opt. -63).
Maintenance procedures hereinafter are
based on re mov al of the controller with the
thermal bulb (12) as a unit from the thermal
well (17) or piping system.
When removing the tubing to/from the con trol ler, tag the tube utilized with either Port
"A" or "B".
There is no maintenance performable to the
ther mal well (17) for the controller. If the
thermal well (17) is corroded, a liquid pres sure test may be performed at the following
maximum pressure levels:
SST Thermal Well —9,300 psig (641 Barg)
Brass Thermal Well —1,500 psig (103
Barg)
There is no maintenance performable to the
thermal bulb (12) portion of the controller. If
SECTION V
6.
7.
B.
1.
2.
the thermal bulb (12) is corroded, a liquid pressure test may be performed at the fol low ing
maximum pressure levels to assure pres sure
integrity.
SST Thermal Bulb — 9,300 psig (641 Barg)
Brass Thermal Bulb—1,500 psig (103 Barg)
Lightly grease all O-rings upon replacement
with lithium grease; cloth wipe all excess
grease.
Place thermal bulb (12) into a vise and grip on
the hex surfaces of the thermal bulb assembly
(12). Orient the pneumatic section upwards.
Pneumatic Circuit Overhaul:
Remove output pressure gage (11) and test
cal i bra tion. If gage (11) is off ±2 psi (±0.14
Bar), replace gage (11).
Using channel lock pliers or similar tool,
loos en knurled lock nut (16) by rotating CCW
(viewed from front). Back lock nut (16) away
from thermal bulb (12) until it is stopped by
contact with the sensor housing (1). Keep
track of the number of rev o lu tions loos ened
for lock nut (16) in table below:
IOM-764T
7
2.
(cont.)
3.
4.
5.
6.
7.
8.
9.
Number of revolutions lock nut is "loos ened" from thermal bulb: ______
Number of revolutions to remove hous ing
from thermal bulb: ______
Remove name plate (10) by re mov ing screw
(9).
Remove four sensor end plate screws (8).
Grasp sensor end plate (2.2) and with draw
vertically from housing (1). Lay sensor sub as sem bly (see Figure 9) on work surface; take
care to not lose sensor pin (2.4) in han dling.
Hand-grasp housing (1) and rotate CCW
(viewed from knob end) to removal. Keep
track of the number of revolutions to removal
in table of Step 2, previous. Take care not to
invert and drop the sensor plate subassembly
(15) from the housing (1) internals in han dling.
Remove thermal bulb (12) from vise, taking
care not to invert and drop Invar rod (13) (also
extension post (14)) of the thermal bulb (12)
and cause end damage to rod (13) (also post
(14)). Examine bulb (12) interior for signs of
leakage; recommend complete 764T re place ment if leakage is discovered.
Holding the housing (1) in a vise, remove the
sensor plate O-ring (6) using an awl-type tool,
and discard. DO NOT DAMAGE METAL
SURFACES!
Remove the housing (1) from the vise, invert
housing (1) with hand covering knob-end to
allow sensor plate subassembly (15) to drop/
slide out of the housing (1); it may be nec es sary
to push adapter (15.2) to remove the sen sor
plate subassembly (15).
11.
12.
13.
14.
15.
16.
17.
18.
Rotate sensor end plate (2.2) CCW (viewed
from sensor end) to removal. Keep track of
the number of rotations to remove the end
plate (2.2) from the ad just ing screw (2.3) in
the table of Step 11.
Remove three O-rings (5) from sensor (2.1).
Pick up housing (1). Using a suitable screw driv er, rotate needle valve (3) CW until it
seats. Keep track of the number of rev o lu tions required to seat the nee dle valve (3) and
record in table below:
Number of revolutions required to seat the
needle valve: _____
Reverse the rotation of the needle valve (3)
and fully remove. Remove needle valve
O-ring (7).
Solvent clean and air blow all internal parts.
Install new O-rings on the needle valve (7),
and three on sensor (5).
Place thermal bulb (12) back into a vise. Insert
Invar rod (13) (also extension post (14)) into
thermal bulb (12).
Re-assemble sensor subassembly (2) end
plate (2.2), adjusting screw (2.3), and sensor
(2.1) per the recorded number of revolutions
of Step 10, this sub-section; this will give
"preliminary" adjustment. See Figure 9 for
"fi nal" adjustment dimensions of the sensor
subassembly (2). Rotate sensor (2.1) as
required to the closest hole avail able to allow
sensor pin (2.4) to be in sert ed; insert pin (2.4).
10.
8
Pick up sensor subassembly (2). Allow sen sor
pin (2.4) to be removed. Rotate sensor (2.1)
CCW (viewed from sensor end) to re mov al.
Keep track of the number of rotations to re move
the sensor (2.1) from the ad just ing screw (2.3)
in the following table:
Number of revolutions to remove sen sor
from ad just ing screw: ______
Number of revolutions to remove sen sor
end plate from adjusting screw: ______
Figure 9: Sensor Sub-Assembly Dimensions
(NOTE: A tem po rary piece of tape may be
used to cover the hole the pin is inserted into,
to prevent the pin from becoming lost.
)
IOM- 764T
19.
20.
21.
22.
Pick up housing (1) and insert sensor plate
subassembly (15) back into the housing (1).
Insert new sensor plate O-ring (6) up against
the sensor plate (15.1).
Holding the housing (1) with the cavity up wards, re-insert sensor subassembly (2)
into the housing (1) cavity. Push fi rmly until
the sensor subassembly (2) end plate (2.2)
reach es the mating face of the housing (1). DO
NOT FORCE INSERTION OF THE SENSOR
SUBASSEMBLY (2). IF NOT CEN TERED
IN HOUSING (1) CAVITY, DAM AGE MAY
OC CUR TO SENSOR O-RINGS (5)!
Rotate sensor end plate (2.2) until the thread ed
hole for screw (9) is directly above the proportional band needle valve (3) opening. Holes
should align for the four end plate screws (8);
rotate as required. Insert screws (8) and fully
tighten in a cross pattern.
(Remove temporary tape of Step 18 pre vi ous
this sub-section.) Re-position name plate (10)
onto sensor end plate (2.2) and align screw
(9) hole; insert and tighten screw (9).
23.
24.
25.
26.
27.
Insert housing (1) threaded end into thermal
bulb (12), rotating the num ber of rev o lu tions
recorded in Step 2, this sub-section.
Rotate knurled locknut (16) the same num ber
of rev o lu tions recorded in Step 2, this subsection. NOTE: Lock nut (16) should be
nearly/already tight; if lock nut (16) is not tight,
fully tighten. If more/less than 1/2 revolution
of the number recorded in Step 2 is required
to tighten lock nut (16), it is recommended
that the housing (1) be removed from the bulb
(12) and that Steps 23 and 24 be repeated.
Insert PB needle valve (3) into housing (1) and
rotate CW until seated. Back out the needle
valve (3) the number of revolutions recorded
in table of Step 13, this sub-section.
Following the above procedure should bring
the re-as sem bled unit "close" to the dis as sem bled setpoint. Re gard less, shop cal i bra tion is recommended.
Reinstall output pressure gage (1) using
suit able pipe thread compound or tefl on
tape. DO NOT APPLY EX CESS THREAD
SEAL ANT!
VI.
1.
2.
3.
4.
5.
6.
SECTION VI
SHOP CALIBRATION
The Model 764T is a "blind con trol ler"; i.e. nonin di cat ing. When installed in the pro cess each
ad just ment of the PB needle valve (3) and/or the
adusting screw (2.3) will affect the setpoint; i.e.
the adjustments are inter-acting.
Install a 1/4" pipe plug in the "OUT PUT" port of
the unit.
Provide an 18 psig (1.2 Barg) IAS to the proper
port as determined by Table 1, Sec tion II.
Leave PB as set in Section V.B.26.
Provide a known temperature bath that is equal to
the desired setpoint temperature. The bath must
be steady in its temperature.
Loosen knurled lock nut (16) 1-2 rev o lu tions.
7.
a.
b.
c.
Insert the thermal bulb (12) such that it is im mersed
to the underneath side of the hex surface of the
bulb (12). Place locking pliers on the hex surface
of bulb (12) to hold fi rmly.
FOR DIRECT ACTION:
8.1.
Rotate adjusting screw (2.3) CW or CCW to
achieve desired set point. If set point cannot
be achieved, go to step b or c.
If the output pressure gage (11) is at 15 psig
(1.03 Barg) or more, decrease the setpoint
tem per a ture by holding the thermal bulb (12)
with locking pliers, and ro tat ing housing (1)
CW (viewed from front face) until the output
pres sure de creas es to 9 psig (0.62 Barg).
If the output pressure gage (11) is at 0 psig
(0.0 Barg), increase the setpoint temperature
by hold ing the thermal bulb (12) with locking
pli ers, and ro tat ing housing (1) CCW (viewed
from front face) until the output pressure in creas es to 9 psig (0.62 Barg).
IOM-764T
9
d.
e.
f.
Using channel locking pliers, tighten knurled
lock nut (16), to allow re mov al from the bath
without the hous ing-to-thermal bulb joint
chang ing with re spect to each other.
Place the thermal bulb into a vise and secure.
Wrench tighten knurled lock nut (16) without
al low ing the housing (1) to "move".
Re-insert the bulb (12) into the bath, and
rotate adjusting screw (2.3) CW or CCW a
few degrees to cause the calibration setpoint
to be repeated. If setpoint is in error, repeat
Sub-Steps a. through f. until correct.
c.
d.
e.
If the output pressure gage (11) is at 0 psig
(0.0 Barg), decrease the setpoint tem per a ture
by hold ing the ther mal bulb (12) locking pliers,
and rotating hous ing (1)CW (viewed from front
face) until the output pressure in creas es to 9
psig (0.62 Barg).
Using channel locking pliers, tighten knurled
lock nut (16), to allow removal from the bath
without the housing-to-ther mal bulb joint
chang ing with re spect to each other.
Place the thermal bulb into a vise and secure.
Wrench-tighten knurled lock nut (16) without
al low ing the housing (1) to "move".
8.2.
a.
b.
FOR REVERSE ACTION:
Rotate adjusting screw (2.3) CW or CCW to
achieve desired set point. If set point cannot
be achieved, go to step b or c.
If the output pressure gage (11) is at 15 psig
(1.03 Barg) or more, increase the setpoint
f.
9.
Remove plug of Step 2, and tem po rary IAS of
Step 3.
Re-insert the bulb (12) into the bath, and
rotate adjusting screw (2.3) CW or CCW a
few degrees to cause the calibration setpoint
to be re peat ed. If setpoint is in error, repeat
Sub-Steps a. through f. until cor rect.
tem per a ture by holding the thermal bulb (12)
locking pliers, and rotating housing (1) CCW
(viewed from front face) until the output pres sure de creas es to 9 psig (0.62 Barg).
SECTION VII
VII.
TROUBLE SHOOTING GUIDE
1. No controller response.
Possible Cause Remedy
A. Sensing thermal bulb loose at screwed A. See remedy 5.A this section. Re-calibrate.
connection to housing.
B. No air supply B1. Check to see if air is avail able at airset.
B2. Check to see if airset fi lter and/or drip-
well is plugged.
C. Improper action; port "A" or "B" C. Reference Tables 1 & 2 herein for de connections reversed. sired action and proper port; reverse
as required.
D. PB needle valve is fully closed. D. Open at least to alignment of match marks on valve's screw head and
housing.
E. Ice formation. E. Use dry air as an IAS medium in cold
weather. Thaw as necessary by use of
air heater. Trace as necessary.
F. Final element operation problem; F. Reference instructions for operation of
i.e. control valve, positioner, fi nal element.
solenoid, etc.
2. Improper control valve action.
Possible Causes Remedy
A. Mismatch of pneumatic hardware. A. Check bench set of actuator. Consider positioner
or booster.
B. Improper action; port "A" or "B" connections B. Reference Tables 1 and 2 herein for desired
are reversed. action and proper port; reverse as required.
10
IOM- 764T
3. Erratic operation; rapid cycling.
Possible Cause Remedy
A. Insuffi cient PB. A. Increase PB in 1/8 rev. increments by
turning the needle valve CCW. Reset
set point as required (Max PB at 1-1/2 revs.)
B. Improper air supply. B1. Supply pressure too high. Reduce airset output
supply pressure to 15-18 psig.
B2. Air supply unsteady. Replace airset.
C. Pulsing process. C1. Poor location of process temperature tap.
Evaluate and consider relocation.
C2. Steady process, if possible.
D. Non-correctable process dynamics. D1. Bypass control valve positioner and directly
load actuator.
D2. Review sizing and characteristic of control valve,
may be oversized. Use restricted trim, ifnecessary.
D3. Consult factory.
4. Sluggish operation; slow action.
Possible Cause Remedy
A. Restricted fl ow(s) A1. Disconnect tubing and blow sensing line.
A2. Check equivalent output tub ing line length against
those indicated herein in Section II.1.c. Relocate
controller, or consider adding an air booster or
positioner at the control valve.
A3. Check for mashed or pinched tubing.
A4. Installation debris. Air-blow lines.
A5. Ice in lines. Use dry air supply.
B. Insuffi cient air supply. B. Increase supply up to 18-20 psig.
C. Too much PB. C. Decrease PB in 1/8 rev. increments. Reset
set point as required.
D. Poor sensing location of thermal bulb. D1. Delete thermal well, if possible. Pack void space
between bulb and well with heat transfer medium.
D2. Evaluate and consider relocation.
E. Too large actuator. E. Add on air booster or positioner at the actuator.
F. Use of alcohols, glycols in freezing weather; F. Remove sensor sub-assembly and lubricate rings.
dissolved lubricant on O-rings.
5. Calibration erratic; frequent setpoint adjustments.
Possible Cause Remedy
A. Sensing thermal bulb loose at screwed A. Piping weight is cantilevered off of instrument
connection to housing. air connections causing unscrewing, and
effecting internal clearances. Change piping or
add supports as required. Recalibrate.
B. Air supply debris. B1. Provide a cleaner air supply or piping source.
B2. Ice in lines. Correct as necessary.
6. Leakage of process fl uid.
Possible Cause Remedy
A. Thermal bulb and/or thermal well failure. A1. Chemical attack. Consult factory.
A2. Severe over-temperature. Replace unit.
7. Cannot reach upper or lower temperature levels of stated range.
Possible Cause Remedy
A. Improper sensor sub-assembly setting. A. Remove sensor sub-assembly. Check dimension
to those indicated in Figure 9 . If dimension is
correct, and high setting cannot be reached,
decrease dim"X" by rotating sensor end plate 1/2
revolution CW; reverse for lower setting.
IOM-764T
11
SECTION VIII
VI. ORDERING INFORMATION
NEW REPLACEMENT UNIT vs PARTS "KIT" FOR FIELD REPAIR
To obtain a quotation or place an order, please retrieve the Serial Number and Product Code that was stamped
on the metal name plate and attached to the unit. This information can also be found on the Bill of Material
("BOM"), a parts list that was provided when unit was originally shipped.) (Serial Number typically 6 digits).
Product Code typical format as follows: (last digit is alpha character that refl ects revision level for the product).
–
NEW REPLACEMENT UNIT:
Contact your local Cashco, Inc., Sales Rep re sen ta tive with the Serial Number and Product code.
With this information they can provide a quotation
for a new unit including a complete description,
price and availability.
CAUTION
Do not attempt to alter the original construction of any
unit without assistance and approval from the factory. All
purposed changes will require a new name plate with appropriate ratings and new product code to accommodate
the recommended part(s) changes.
–
7
PARTS "KIT" for FIELD REPAIR:
Contact your local Cashco, Inc., Sales Rep re sen ta tive with the Serial Number and Product code.
Identify the parts and the quantity required to repair
the unit from the "BOM" sheet that was provided
when unit was originally shipped.
NOTE: Those part numbers that have a quantity indicated
under "Spare Parts" in column "A” refl ect minimum
parts required for inspection and rebuild, - "Soft
Goods Kit". Those in column “B” include minimum
trim replacement parts needed plus those "Soft
Goods" parts from column "A".
If the "BOM" is not available, refer to the crosssectional drawings included in this manual for part
identifi cation and selection.
A Local Sales Representative will provide quotation
for appropriate Kit Number, Price and Availability.
The contents of this publication are presented for informational purposes only, and while every effort has been made to ensure their accuracy, they are not to be construed as warranties or guarantees, express or implied, regarding the products or services described herein or their use or applicability. We reserve the right to modify
or improve the designs or specifi cations of such product at any time without notice.
Cashco, Inc. does not assume responsibility for the selection, use or maintenance of any product. Responsibility for proper selection, use and maintenance of any
Cashco, Inc. product remains solely with the purchaser.
12
IOM- 764T
NOTE: High Temperature Thermal Bulb (Opt-63)
sectional drawing and item number callouts may be
found on page 4. Figure 6.
Figure 10
Item No. Description
1 Housing
2 Sensor Subassembly
2.1 Sensor *
2.2 End Plate *
2.3 Adjusting Screw *
2.4 Sensor Pin *
2.5 Retaining Clip *
3 Needle Valve
5 O-ring - Sensor
6 O-ring - Sensor Plate
7 O-ring - Needle Valve
8 End Plate Screw
9 Name Plate Screw
10 Name Plate
11 Gauge
IOM-764T
Item No. Description
12 Thermal Bulb Assembly
13 Sensing Rod
15 Sensor Plate Sub as sem bly
15.1 Sensor Plate
15.2 Adaptor
15.3 Retaining Ring
15.4 Spring
16 Lock Nut
Not Shown:
17 Thermal Well
* Not Sold as individual parts.
(Purchase Sensor Sub-Assembly 2)
13
NOTES
14
IOM- 764T
NOTES
IOM-764T
15
Cashco, Inc.
P.O. Box 6
Ellsworth, KS 67439-0006
PH (785) 472-4461
Fax. # (785) 472-3539
www.cashco.com
email: sales@cashco.com
Printed in U.S.A. 764T-IOM
Cashco GmbH
Handwerkerstrasse 15
15366 Hoppegarten, Germany
PH +49 3342 4243135
Fax. No. +49 3342 4243136
www.cashco.com
Email: germany@cashco.com
Cashco do Brasil, Ltda.
Al.Venus, 340
Indaiatuba - Sao Paulo, Brazil
PH +55 11 99677 7177
Fax. No.
www.cashco.com
Email: brazil@cashco.com
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