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Installation/
Operation
Maintenance
™
VariT rane
Pneumatic Controls
March 2002 VAV-SVX02B-EN
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Thermostat Figure 1–Two-Pipe Remote Thermostat (Reverse-Acting) Thermostat Selection and Location In general, both one- and two-pipe Tee thermostats have a gain of 2.5 psi per Two-Pipe degree Fahrenheit, unless special Remote-Mounted thermostats are used that provide a T-Stat different gain. The major difference (Reverse-Acting) between them is that a one-pipe thermostat is considered a low- capacity thermostat and a two-pipe thermostat is considered a high- capacity thermostat. When selecting b
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Thermostat Specifications Operation Figure 4 illustrates the pressure/ temperature characteristics for a TP970 Series Pneumatic T-stats Pneumatic thermostats modulate reverse-acting thermostat. As room output air pressure in response to room Maximum Safe Air Pressure: temperature increases, the thermostat air temperature. Pneumatic thermo- 25psi (172 kPa) output pressure decreases. stats fall into two categories: direct- Maximum Safe Air Temperature: acting or reverse-acting. This section 150°F
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Reversing Relay Figure 6–Reversing Relay Connections Installation and Operation The reversing relay is a proportional, non-bleeding device for use in pneu- Output matic control systems where a propor- S Branch tional signal from a controlling device must be reversed (see Figure 5). The 20 most common use of the reversing (137.9) relay is to change the action of a pneumatic thermostat. Figure 5–Pneumatic Reversing Relay Trane Part No. RLY-755 9 PSI In B (62.06 kPa) Reversing M Relay 9 PSI Out S (
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Reversing Relay Calibration Figure 8–Recalibrating Reversing Relay By using the “bias” adjustment on the relay, the factory-set 8.0–9.0 “cross- over” can be changed. To recalibrate, Gage the relay should be connected as illustrated in Figure 8. 1 Pressure Bias Regulator C Adjustment M Screw 3 M If the new desired “cross-over” pressure is 11.0 psi, this must be applied to port #3 by adjusting the pressure regulator . The “bias” adjustment is then turned until 11.0 psi is obtained on the output ga
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I I N N N N Model 3011—Pneumatic Volume Regulator Installation Model 3011 The model 3011 Pneumatic Volume 1. Attach bracket either vertically or horizontally to the illustration surface. Horizontal Regulator (PVR) is capable of operating is preferred, vertical is acceptable, any other position is not acceptable (see Figure 9). with normally-open or normally-closed 2. Insert controller into its bracket. Controller may be face up, face down, face left, or air valves and can operate with either fac
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I I N N I I N N N N Model 3011—Pneumatic Volume Regulator Use the following procedure to set-up the PVR: 1. Select damper action (NO or NC). Loosen damper selection switch screw and align to either the NO or NC pointer with damper pointer and tighten screw. 2. Now determine the type of thermostat that will be used. If a direct-acting thermostat is used, the reset start pressure is typically 8 psi. If a reverse-acting thermostat is used, the reset start pressure is typically 3 psi (see Figure 11)
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NO I I I N N N N N N Calibration Procedures Calibration Procedure (Steps 1–4 apply to all thermostat models) 1. Be sure the PVR is installed correctly and that all connections are hooked up to the proper ports. See Figure 9 for unit application. 2. Remove the caps on the tees which are connected to the lines to the flow sensor. Connect a 0–2" magnehelic gage to monitor flow sensor delta P . The higher-pressure port is further upstream on the air valve inlet. 3. Remove the thermostat line and con
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Specifications (3011) Specifications (3011) Normal Supply Air Pressure: Reset Span Range: 20.0 psi 0–10 psi Differential Pressure Range: 0 to 1.0 in. wg Minimum Supply air Pressure: Maximum Safe Thermostat Input: Minimum Setpoint Range: 15.0 psi 30 psi (closed chamber) 0 to 1.0" H O 2 Maximum Supply Air Pressure: Operating T emperature: Maximum Setpoint Range: 30.0 psi +40/+120°F minimum to 1.0 in. wg Average Supply Air Consumption: Storage T emperature: Operating Static Range: 28.8 scim at 20 p
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Model 3501—Pneumatic Volume Regulator Installation Adjusting the Reset Span (3501) Model 3501 1. Attach bracket either vertically or The reset span is factory-set at 5 psi. The model 3501 Pneumatic Volume horizontally to the installation surface. This is the thermostat pressure differ- Regulator (PVR) is capable of operating Horizontal is preferred, vertical is ence from which the PVR delivers with normally-open or normally-closed acceptable, any other position is flow from minimum to maximum ai
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Calibration Procedures Calibration Procedure (Steps 1–4 apply to all thermostat models) 1. Be sure the PVR is installed correctly and that all connections are hooked up to the proper ports. 2. Remove the caps on the tees, which are connected to the lines to the flow sensor. Connect a 0–2" magnehelic gage to monitor flow sensor delta P . The higher-pressure port is further upstream on the air valve inlet. 3. Remove the thermostat line and connect a hand pump with a 0–20 psi gage to port “T“ . 4.
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Specifications (3501) Specifications (3501) Output Sensitivity: 5 psi/.02 Differential Pressure Range: 0 to 1.0 in. wg Average Supply Air Consumption: Minimum Setpoint Range: 43.2 scim at 20 psi 0 to 1.0" H O 2 Reset Start Point Range: Maximum Setpoint Range: 0–10 psi minimum to 1.0 in. wg Reset Span Range: Maximum Setpoint Range: 0–7 psi 6.0 in. wg Operating T emperature: Normal Supply Air Pressure: +40/+120°F 20.0 psi Storage T emperature: Minimum Supply air Pressure: -40/+140°F 15.0 psi Maxim
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MCP-3631—Rotary Pneumatic Damper Actuator Installation Method: Specifications: MCP-3631—Rotary Slide collar onto shaft. Slide actuator Effective Area: Pneumatic Damper Actuator onto shaft noting directional rotation. 8 sq in. (52 sq cm) Description: Slide bushing onto shaft into actuator, Normal Rotation: Rotary actuators mounts to a standard aligns actuator with damper, lock 100 deg ½" diameter shaft by a locking collar collar and bushing set screws, and Supply Pressure: and bushing. install br
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Constant-Volume Dual-Duct Calibration (3011) This PVR does not require a thermostat 3. Set t-stat to full cool. Constant V olume Dual-Duct connected to the PVR. 4. Set HI thermostat (minimum) to Calibration (3011) the desired minimum flow on the The following procedure must be used This calibration procedure is used when heating deck. when calibrating a constant-volume a constant volume of air must be 5. Set LO thermostat adjustment knob dual-duct unit. See Figure 15 for a maintained through a u
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Variable Air Volume Dual-Duct Calibration (3011) Figure 16–Typical VAV Dual-Duct Piping Diagram Variable-Air-Volume Dual- Duct Calibration (3011) Figure 16 is a typical piping diagram of Outlet a VAV dual-duct unit. The unit has a thermostat piped to both pneumatic T H L Heating g Cooling g volume regulators (PVR) which will V Vallve V Vallve B Actuator Volume operate the heating deck from a Normally- Normally- Regulator O Open O Open thermostat signal of 3–8 psi. The cooling LO LO HI HI deck wi
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Constant-Volume Single-Duct VAV (VCV 3011) 1. Be sure there is 0 psi at the “T” port. Constant-Volume Single- 2. Set LO thermostat adjustment knob to Duct VAV ( VCV 3011) desired unit cfm. This is used when a constant volume of The unit will now modulate to the air is required to supply a zone. A calibrated cfm setting. See Figure 18 for thermostat is still often required to typical constant volume single-duct modulate a reheat coil to maintain piping diagram. temperature control. The thermosta
