Powers Controls
Contents
1. the ball valve closing both the exhaust and the supply valves against the ball This throttles the supply air in an inverse proportion to the temperature change established by the sensitivity spring As the temperature drops the motor tube contracts moving the ball valve away from the supply valve gradually increasing the return line air supply valve port Higher pressures in the return air chamber increase force against the exhaust valve diaphragm The sensitivity spring compresses and the ball valve moves gradually to the supply valve reducing the supply air volume to the return air chamber The throttling range is changed by sliding the sensitivity spring Sensitivity is most gradual 0 25 psi 1 F or 3 1 kPa C when the spring s open end is under the adjusting screw Throttling is most positive 2psi 1 F or 24 8 kPa C when the solid end of the spring is under the adjusting screw Factory setting is at the center of the sensitivity spring or 1 1 4 psi 1 F or 15 5 kPa C Any change to the spring s position offsets control and makes resetting of the dial necessary Return line vent factory set for 5 to 7 CIM 1 37 to 1 91cm s prevents the air being trapped in the line when the Limitem is piloted from a room thermostat Siemens Industry Inc Page 3 Technical Instructions Document No 155 070P25 September 24 2004 Installation NOTE Calibrate the Limitem for your application after installation Duct Mounting See Figur2. SIEMENS Technical Instructions Document No 155 070P25 TH 356 1 September 24 2004 Powers Controls TH 356 Limitem Rigid Bulb Thermostat Description Features Product Numbers Application TH0031R1 The TH 356 Rigid Bulb Limitem is a pneumatically operated thermostat available either as direct acting or reverse acting in a variety of ranges e Copper motor tube and invar steel rod sensing element e Two valve design eliminates wasting of air e 18 inch 457 mm bulb useful where stratification occurs e Flange locknut and screws for duct mounting included Table 1 Product Operating Range Number 356 0750 30 to 180 F 1 to 82 C 356 0012 0 to 100 F 18 to 38 C 356 1005 30 to 180 F 1 to 82 C Reverse 356 1006 100 to 250 38 to 121 C Acting 356 0013 Oto 100 F 18 to 38 C The 356 Rigid Bulb Limitem is recommended for use in controlling duct air temperatures such as mixed air or discharge air It can also be used as a high or low temperature limit control In unit ventilator applications it is used as a low limit control When used with a well it can be used for water temperature control Siemens Industry Inc Technical Instructions Document No 155 070P25 September 24 2004 if nati Operating range See Table 1 SpecHications Normal air supply pressure 18 or 25 psi 124 or 172 kPa Maximum supply air pressure 30 psi 207 kPa Maximum external pressure on bulb 250 psi 1 722 kPa M
3. aximum ambient temperature case 200 F 93 C bulb 30 to 180 F 225 F 107 C 100 to 250 F 250 F 121 C 40 to 120 C 250 F 121 C 0 to 100 F 250 F 121 C 20 to 40 C 250 F 121 C Factory sensitivity setting 1 1 4 psi F 15 kPa C Sensitivity range adjustable 1 4 to 2 psi F 3 to 25 kPa C Temperature response 1 2 F 0 9 C Mounting Flange or 3 8 inch NPT Air connection 1 8 inch NPT Shipping weight 2 lbs 0 9 kg Dimensions Bulb length 18 inches 457 mm Case 3 in L x 1 1 2 in diameter 76 mm x 38 mm Flange O D 2 9 16 in 65 mm Accessories Gauge tees pkg of 5 141 436 Pipe plug 403 007 Well copper 358 051 Swivel flange mounting kit 356 090 Flange mounting screw 3 required 034 256J Replacement gauges 0 to 30 psi bottom P142 308 0 to 30 psi 0 to 200 kPa back P142 373 TEST BLEED TEST _ BLEED PORT screw EXHAUST VALVE EXHAUST VALVE SENSITIVITY SENSITIVITY EXHAUST covER EXHAUST COVER VALVE VALVE THOO32R1 THO033R1 DIAPHRAGM SUPPLY VALVE DIAPHRAGM SUPPLY VALVE Figure 1 Direct Acting Operation Figure 2 Reverse Acting Operation Page 2 Siemens Industry Inc TH 356 Limitem Rigid Bulb Thermostat Technical Instructions Document No 155 070P25 September 24 2004 Operation The copper motor tube and invar steel rod average temperature changes by measuring the difference in expansion between the two metals This positions the two valve mechanism in response to t
4. e 3 THOO10R1 Flange lock nut and sheet metal screws are provided for duct mounting 1 Remove the flange from the Limitem and use the flange as a template Mark the location of the center hole and three screw holes Drill the holes 2 Slip the flange over the rigid bulb and secure with the lock nut 3 Fasten the Limitem to the duct with the sheet metal screws provided 4 Attach air gauges and tees in the supply and return lines The installation is now complete 10 SCREW CLEARANCE HOLES ON A 2 13 64 56 DIA BOLT CIRCLE 3 HOLES EQUALLY SPACED 60 SB oviba Axes 100s 7 So F LIMITEM 47 1 11 32 34 13 32 10 LONG X 13 64 5 WIDE SLOT TO SIMPLIFY MOUNTING ON UNIT VENTS 1 4 O D TUBE GAUGE TEE OPTIONAL AIR RETURN 1 8 NPT AIR SUPPLY 1 8 NPT 2 3 16 FLANGE SHEET METAL SCREW 3 PLACES 7 16 11 DIA 3 8 NPT 18 1 4 TH0193R1 55 Figure 3 TH 356 Rigid Bulb Limitem 463 Alternate Duct Mounting The swivel flange mounting kit Part No 356 090 is available for mounting the Limitem in Swivel Flange Mounting See Figure 4 Page 4 ducts as small as 13 inches 330 mm wide 1 Use the swivel flange as a template to mark the location of the center hole and three screw holes 2 Drill the holes and attach the flange 3 Remove the standard mounting flange from the Limitem 4 Carefully thread the Limite
5. he sensitivity spring tab location and the corresponding sensitivity value NOTE The tab may be installed in either side of the spring retainer 5 Make sure that the dial adjustment screw point touches the sensitivity spring 6 Recalibrate the unit 7 If you need to adjust again allow five minutes for the control cycle to settle before repeating the steps above Siemens Industry Inc TH 356 Limitem Rigid Bulb Thermostat Technical Instructions Document No 155 070P25 September 24 2004 Sensitivity Adjustment continued Table 1 lt a ll Sensitivity Psi F SENSITIVITY POSITIVE CONTROL GRADUAL CONTROL DIAL ADJUSTMENT SENSITIVITY SCREW SPRING SPRING RETAINER THOO18R1 THOO19R1 EXHAUST VALVE Figure 8 Sensitivity Spring Setting n If the limitem fails to operate properly use Table 3 as a troubleshooting guide Make certain the thermostat receives 18 to 30 psi 124 to 207 kPa of clean dry oil free supply air Also use a test gauge with a length of 3 16 I D rubber hose to measure the return pressure at the test port if permanent gauges are not available Service The limitem cannot be serviced Replace the thermostat if inoperative after checking the troubleshooting table Table 3 Troubleshooting Chart Complaint Probable Cause Corrective Action Return Line pressure Supply air Pressure As Required stays at TEASA Depress exhaust If return is still Defective valve Replace thermostat
6. he slightest temperature changes Direct Acting As temperature increases the motor tube expands and moves the supply valve away from the ball valve causing a gradual increase of air pressure in the return line The ball valve is closed against the exhaust valve while the supply valve is open preventing constant air waste Increased pressure in the return air chamber causes the exhaust valve diaphragm to compress the sensitivity spring The exhaust valve is moved away from the ball valve closing against the supply valve This throttles the supply air in proportion to the temperature change established by the sensitivity spring As the temperature drops the motor tube contracts This moves the ball valve away from the exhaust valve and gradually reduces the return line air through the exhaust port Lower pressures in the return air chamber force against the exhaust valve The sensitivity spring expands and the exhaust valve moves gradually to the ball valve reducing the return air waste Reverse Acting As temperature increases the motor tube expands and moves the supply valve and the ball valve away from the exhaust valve causing a gradual decrease of air pressure in the return line The ball valve is closed against the supply valve while the exhaust valve is open preventing air waste Decreased pressure in the return air chamber causes the exhaust valve diaphragm to allow the sensitivity spring to expand The exhaust valve is moved toward
7. hermometer accurately measure the temperature at the bulb 2 Set the dial to the bulb temperature by turning the dial adjustment screw with a screwdriver NOTE You must use a screwdriver Do not attempt to change the dial by rotating it with your hand 3 If permanent return air gauge is not installed use the pressure test port See Figure 6 for its location 4 Loosen the test port screw about 1 2 turn and slip a 3 16 inch I D rubber hose connected to the test gauge over the pressure test port See Figure 7 5 Ifthe return pressure does not read 7 to 8 psi 48 55 kPa turn the dial adjustment screw with a screwdriver until pressure is 7 to 8 psi 48 55 kPa 6 Loosen the dial screws and turn dial until the temperature at the bulb and dial is identical Tighten the screws The thermostat is now calibrated and setpoint may be changed as desired The sensitivity adjustment is factory set with the sensitivity spring tab in position 6 of the spring retainer This is approximately mid span of the sensitivity Move the sensitivity spring to a lower slot number for more gradual setting Move the sensitivity spring to a higher slot number for more positive setting See Table 2 To change the sensitivity 1 Loosen the dial screws See Figure 6 2 Loosen the dial adjustment screw 3 Lightly press but do not bend the spring retainer See Figure 8 4 Move the sensitivity spring to the new position See Figure 8 Table 2 gives t
8. m through the 3 8 inch NPT tapped swivel socket 5 Fasten the flange to the duct with the sheet metal screws provided The installation is now complete Siemens Industry Inc TH 356 Limitem Rigid Bulb Thermostat Technical Instructions Document No 155 070P25 September 24 2004 Installation continued Figure 4 Swivel Flange Mounting Kit part No 356 090 Well Mounting 1 Exercise care when installing the limitem into a well See Figure 5 ie 2 The Limitem must fit freely in the well to operate properly 3 Screw the limitem into the well finger tight 4 Tighten the set screw on the well to hold the limitem securely The installation is now complete 18 7 8 479 NO 10 32 SET SCREW dad 17 7 16 Figure 5 Limitem Well Mounting Kit Part No 358 051 443 THOOO9R1 Calibration 1 Remove the cover To Change Setpoint 2 Turn the dial adjustment screw with a screwdriver Figure 6 to change to the desired setpoint POINTER DIAL SCREW 2 PLS SUPPLY D S DIAE F 0 Powers 20 PRESSURE ADJUSTMENT E TEST PORT SCREW PRESSURE RETURN TEST PORT PORT 2 TEST PORT TEST SCREW GAUGE z Figure 6 Limitem Cover Removed Figure 7 Using the Pressure Test Port Siemens Industry Inc Page 5 Technical Instructions Document No 155 070P25 September 24 2004 Calibration continued To calibrate Sensitivity Adjustment Page 6 1 Using a test t
9. ousingRing 1 8 SupplyValve 1 9 Supply Valve Diaphragm 1 3 48 x 7 8 Lg Fil Head ft Screw 12 DuctFlange i 13 Washer Jij KF 14 tocknut i 15 Flange Jij 16 Motor Tube Assembly 1 0 Ring a o a 18 ScreenFilter 2 Table 4 Parts List continued Af e 2 Spring 2 item Body Lower Spacer 2 1 EN 6 32 x 1 7 8 Lg Fil hd machine screw aia 34 TestValveBody 1 35 ValveGasket 1 36 Pointer dT 1 Information in this publication is based on current specifications The company reserves the right to make changes in specifications and models as design improvements are introduced Product or company names mentioned herein may be the trademarks of their respective owners 2004 Siemens Industry Inc Siemens Industry Inc Building Technologies Division 1000 Deerfield Parkway Buffalo Grove IL 60089 1 847 215 1000 Your feedback is important to us If you have comments about this document please send them to sbt_technical editor us sbt siemens com Document No 155 070P25 Printed in the USA Page 8
10. zero psi assembly If return Out of calibration 1 Recalibrate pressure or ae t 2 With 6 to 9 psi return pressure vary eRe Sensing e emen temperature at the bulb If no change in return pressure replace thermostat Return Line pressure Using a If return Defective valve Replace thermostat stays at approx screwdriver pressure assembly supply pressure rotate setpoint remains high dial counterclock wise a limit pressure drops p to zero Excessive air leakage Supply and return line connection Connections are Reverse the supply and return connections from exhaust valve interchanged Temperature cycles Sensitivity setting Improper setting Move the sensitivity spring to a more gradual rapidly lower slot setting See Sensitivy Adjustment If return Out of calibration Recalibrate Temperature wanders Sensitivity setting Improper setting Move the sensitivity spring to a more positive from control point higher slot setting See Sensitivity Adjustment Siemens Industry Inc Page 7 Technical Instructions Document No 155 070P25 September 24 2004 8 9 40 41 12 THO199R1 30 29 28 27 26 25 24 23 22 Figure 9 Construction of the Rigid Bulb Limitem Table 4 Parts List Item Part ty Part Number 1 Cover Jif 2 ial Jif 3 tockPlae 1 4 Bride i 5 UpperSpacer_ 2 Ka I 6 32 x 1 3 8 Lg Fil Hd screw 7 H
Download Pdf Manuals
Related Search