HONEYWELL T991A Remote Bulb Temperature Controller User Manual

APPLICATION

The T991A Remote The T991A Remote Bulb Temperature Controller is Bulb Temperature Controller is used to sense water and air temperatures, used to sense water and air temperatures, and pro­ and pro- vides proportional vides proportional control of a Series 90 (Modutrol) control of a Series 90 (Modutrol*) motor.
Typically, Series SO motors are used with linkages to operate valves or dampers in air cmdi- motor. Typically, Series 90 motors are used with linkages to operate valves or dampers in air condi­ timing systems.
The TSSlA cm be used to replace the controliers listed below: tioning systems.
The T991A can be used to replace the controllers listed below:

T915A.
T915C| See Table 1 for corresponding See Table 1 for corresponding T991A T9SlA temperature settings.

INSTALLATION

NOTE: Installation and service should be made only by a quaiiCied service mm. Follov instruciions lu- nished by heating or cooling system manufacturer, if available.
NOTE: Installation and service should be made only by a qualified service man. Follow instructions fur­ nished by heating or cooling system manufacturer, if available.
LOCATION: The T99AA may be mounted in any convenient posi­ tion on a flat surface where the ambient temperature does not exceed 125 F. When mounting on a hot or cold surface, mount the case on a wood board or other insulating material. The 5-foot capillary tube provides for remote mounting.
Proceed to the FOR NEW INSTALLATION section or FOR REPLACEMENT or FOR REPLACEMENT section. section.

FOR NEW INSTALLATION:
MOUNT THE CONTROLLER CASE–

1. Remove cover. Using the case as a templa.te, mark three screw hole locations on mountinz surface, then punch or drill holes.
2. Fasten T991A securely to mounting surface with the mounting screws furnished. the mounting screws furnished.

TO INSTALL SENSING BULB IN AIR DUCT:
Locale the sensing bulb where duct air of average Locate the sensing bulb where duct air of average temperature can circulate freely around ii. Avoid mounting the bulb close to hot pipes, cooling coils, and other places where air  temperatures are not representative.
To support the bulb in Lhe duct, use Bulb Hoider No. 107324A (supplied).
temperature can circulate freely around it. Avoid mounting the bulb close to hot pipes, cooling coils, and other places where air temperatures are not representative.
To support the bulb in the duct, use Bulb Hoder No, 107324A (supplied).

1. Drill a 3/4-inch hole in the duct wall to admit the sensing bulb and the holder.
2. Using the holder as a template, mark and drill holes for bulb holder mounting screws (see Fig. 4).
3. Break off bulb holder to desired length, as the sensing bulb and the holder.
   +Trademark
   3-64 R.T.
   T991A REMOTE BULB.

TEMPERATURE CONTROLLER
shown in Fig. 2. NOTE: shown in Fig.2. NOTE: Holder should be long enough Holder should be long enough to hold sensing bulb in freely circulaiing to hold sensing bulb in freely circulating air, away from duct wall. Neatly coil any excess capillary air, away from duck wail. Neatly coil any excess capillary tubing at controller case or at bulb holder.
tubing at controller case or at bulb holder.

1. Place capillary tubing in bulb holder channel, and pinch topedges of holder together aleach segment:
2. Insert bulb and holder into controlled area through hole prepared in Step 1.
3. Fasten bulb holder to duct wall with screws furnished.

TO INSTALL SENSING BULB IN TANKS OR BOIL- ERS –

The T991A sensing bulb may be inserted  directly  into a tank or boiler tapping by “sig a No. 7617M  TO INSTALL SENSING BULB IN TANKS OR BOIL­ ERS ­ The T991A sensing bulb may be inserted directly  into a tank or boiler tapping by using a No. 7617M  (M-inch NPT) or 76172 (3kinch  NPT) Compression  Fitting (order separately);

or the element may be  inscried  into a No. 112622AA  (&‘-inch  NPT)  or 112G30AA  (3/4-inch NPT) Immersion  Well  (order  separately)  which  is screwed  into iheianlr or boiler.

(1/2 -inch NPT) or ‘7617P (3/4-inch NPT) Compression Fitting (order separately); or the element may be inserted into a No. 112622AA (12-inch NPT) or 112630AA (3/4 -inch NPT) Immersion Well (order separately) which is screwed into the tank or boiler.

1. Drain system. Screw boiler plug into properly sized and threaded boiler or pipe tapping.
2. Place packing nut 011 T99iA capillary lube.
3. Slide sensing bulb compieieiy tko”gh boiler p,i,g.
4. Place composilion disc and the 4 slotted brass washers on tubing in the order shown in Fig. 6.
5. Slide the assembly into the boiler plug, and tighte” the packing nul.
6. ReIill the sysiem and check for leaks. Neatly coil cxccss capillary tubing at T991A case. sized and threaded boiler or pipe tapping.

Installing Immersion Well (not furnished)—

1. Drain system. Screw the well into properly sized and threaded boiler tapping or pipe fitting.
2. Refill the system and check for leaks.
3. Insert sensing bulb into well until it bottoms.
4. Fit bulb retaining clamp over immersion well clamp over immersion well flange and capillary lange and capillary tubing, and tighten screw, as shown in Fig. 7.
   Neatly coil excess capillary tubing at T991A case.

FOR REPLACEMENT:

Remove old controller. Mount T991A in same lo-cation if this meets the reauirements in LOCATION, above.
Use old sensing bulb hole, bulb holder, immersion well, or compression fitting if these are suitable; otherwise, foilow applicable instructions for new in- stallation, above.
See Table 1 in SETTINGS AND ADJUSTMENTS.
WIRING
All wiring must comply with local electrical codes.
CAUTION: Disconnect power supply.
Fowl knockouts are provided at top and bottom of case for 12-inch conduit. Follow any wiring instruct- tions furnished with heating or cooling system. In replacements, make certain the T99LA is wired in the system to operate the same way as old control.

SETTTINGS AND ADJUSTMENTS

Temperature set point—Turn knob on front of case until pointer indicates temperature which is to be maintained in the controlled medium. This is the center point of the proportional range.
Porportional range adjustment–The T991A may be adjusted to vary the temperature range within which proportional action is desired. With cover off, turn adjustment wheel (marked 3, 5, 10, 20, 30) until de- sired value is aligned with pointer on frame.
EXAMPLE: If the temperature of the controlled medium is to be matntained at 130 F, and propor- tional action from 125 F to 135 F (a range of 10 de- grees) is desired—turn the temperature set point indicator to 130 F and the proportional range adjust- ment wheel to 10.

WHEN REPLACING A T915A—
Set the T991A temperature set point to same setting as old control (from 55 te 140 F). Set T991A propor- tional range adjustment wheel to 3.
WHEN REPLACING A T915C—See Table 1.

TABLE I–TRIAL SETTINGS FOR T99IA WHEN REPLACING A T915C

aThe Tradeline aThe Tradeline T991A proportional range is from 3 to 30 degrees F. If the application exceeds the T991A proportional range is from 3 to 30 degrees F.
If ihe application exceeds the 30.degree proportional 30-degree proportional range, then a T915C must be used or a repaired exchange T915C must be ordered. range, then a T915C must be used or a repaired exchange T915C musi be ordered.

CHECKOUT

After After mounting and wiring have been completed, let mounting and wiring have been conipleted, let the controlled equipment operate until system tem- the controlled equipment operate until system tem­ perature perature stabilizes (from 1 to 3 hours). Observe the stabilizes (from 1 to 3 hours).
Observe the motor action to see if ii stabilizes.
If the motor shaft Constantly mo”es backand forth, widen the T991A proportionalrange (about 5 degrees ai a time) until the system is stable.
motor action to see if it stabilizes. If the motor shaft constantly moves back and forth, widen the T991A proportional range (about 5 degrees at a time) until the system is stable.

By using this Honeywell literature, you agree that Honeywell will have no liability for any damages arising out of your use or modification to, the literature. You will defend and indemnify Honeywell, its affiliates and subsidiaries, from and against any liability, cost, or damages, including attorneys’ fees, arising out of, or resulting from, any modification to the literature by you.

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