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ASHRAE Guideline 11-2018 - Field Testing of HVAC Controls Components, 2018
- ASHRAE Guideline 11-2018 [Go to Page]
- CONTENTS
- FOREWORD
- 1. PURPOSE
- 2. SCOPE
- 3. DEFINITIONS
- 4. GENERAL FORMAT FOR TESTING [Go to Page]
- 4.1 Reasons for Testing. The components of control systems are essential for heating, ventilating, air-conditioning, and refrigeration (HVAC&R) systems to properly and efficiently perform their functions. Sensors monitor and report on conditions and ...
- 4.2 Testing Parameters and Accessibility for Testing. The following parameters are necessary to properly test a device or system:
- 4.3 General Testing Procedures
- 5. DEVICE TESTING—BASIC REQUIREMENTS [Go to Page]
- 5.1 Basic Requirements of Sensors and Devices
- 5.2 Air Temperature Sensors
- Figure 1 Temperature sensor and room sensor.
- Figure 2 Duct sensor.
- Figure 3 Averaging-type duct sensor
- Figure 4 Outdoor temperature sensor.
- 5.3 Pressure Measuring Devices
- Figure 5 Duct sensor.
- 5.4 Airflow Measurement. An airflow sensor monitors and reports the presence of air velocity and directly measures or calculates the volume or the existence and/or direction of flow at the sensing location. The location of airflow measurement or dete...
- Figure 6 Differential pressure sensor.
- 5.5 Humidity Sensing Devices. Relative and specific (dew- point temperature) humidity sensing devices monitor and report percent relative humidity (% RH) or dew-point temperature of the surrounding air or airstream to the connected system. Certain hu...
- Figure 7 Duct flow sensor.
- 5.6 Quality Devices. Controls for indoor air quality are used to provide alarms or to control air ventilation rate. Because many of these devices are not stable over time, it is important to initially calibrate the device and to require frequent reca...
- Figure 8 Terminal unit flow sensor.
- Figure 9 Humidity sensor and room humidistat.
- 5.7 Basics of Water-System Devices. Water-system control devices measure the same conditions as the air systems, namely static, velocity, and total and differential pressures. However, because water is noncompressible, it is somewhat easier to test. ...
- 5.8 Water Temperature Sensors. Water temperature measurements are typically made with resistance temperature detectors (RTDs) and thermistors similar to those used in air temperature measurements, and the same precautions are to be taken to ensure th...
- Figure 10 Water temperature sensor.
- 5.9 Water Pressure Sensors. Water pressure measurements are typically defined as either static or differential. Static pressure, or gage pressure, is defined as the difference between water pressure measured at a given point and atmospheric pressure....
- 5.10 Water Flow Devices. Water flow rate measurements are typically measured in gallons per minute (litres per second) using pressure-difference type devices (orifice, nozzle, or venturi tube), turbines, Pitot tubes, or electromagnetic or ultrasonic ...
- Figure 11 Water level sensor.
- 5.11 Water Level Devices. Water level in a distribution system, reservoir, or tank generally uses a device measuring the pressure difference between a reference point and atmosphere or by an electromechanical float device (see Figure 11). Both device...
- 5.12 Basics of Controlled Device Testing
- 5.13 Output Devices. Output devices are generally used to control motors or other equipment based on parameters monitored by the output device. Some of these devices include variable-frequency drives (VFDs) for motor speed control, freeze stats for c...
- Figure 12 Low-temperature limit switch.
- Figure 13 Duct smoke detector.
- 5.14 Electrical Testing. Electrical testing is performed to verify the correct amperage and voltage serving the mechanical equipment. Motors rely on correct voltage and on the amperage operating within the design range, as indicated on the motor name...
- 5.15 Rotating Equipment Testing. Testing of rotating equipment is performed with a calibrated tachometer or strobe light. Tachometers can be a direct-contact type when the shaft end is accessible and has a center location hole, or a photo type that r...
- 6. SYSTEM COMPONENT TESTING [Go to Page]
- 6.1 Basics of System Component Testing. Testing connected systems of mechanical equipment and sensors verifies the performance of the system and the correct and accurate operation of the sensors. The system testing verifies equipment performance to t...
- Figure 14 Single-duct VAV.
- 6.2 Air-Terminal Units
- Figure 15 Dual-duct VAV.
- Figure 16 Dual-duct box—single controller (left) and dual controllers (right).
- Figure 17 Parallel fan-powered box.
- Figure 18 Series fan-powered box.
- 6.3 Air Systems
- 6.4 Testing Water Systems Control
- 7. SEQUENCE OF OPERATION [Go to Page]
- 7.1 Basic Requirements. Testing the sequence of operation of a control system includes the development of test procedures and the documentation of the operation and performance testing.
- 7.2 System Variations. Prior to the initiation of the verification test plan, the following checks are to be completed:
- 8. PROBLEM SOLVING/CRITICAL TESTING [Go to Page]
- 8.1 General Considerations. The purpose of this section is to describe the general procedures to be followed in the testing of control systems. The testing of control systems is divided into four distinct sequences:
- 8.2 Verification of Sensors. Prior to verifying sensor calibration, it is advised that the following items be confirmed:
- 8.3 Verification of Actuators. Actuator operation verification includes the following:
- 8.4 Verification of Controllers and/or Program Functions. Controller and/or program function verification is accomplished by systematically manipulating individual inputs or set points and verifying that the responses meet the system or project requi...
- 8.5 Verification of Integrated System Operation. The final step is to ensure that the individual components of an HVAC system function together. (Example: Verify that the preheat and cooling coils are not operating at the same time.)
- 8.6 Advanced Testing Repeatability and Accuracy Loop- Tuning Checkout. Tuning of controllers and/or programs to improve the performance of a control system is not to be undertaken without first controlling the system by overriding various set points ...
- 9. DOCUMENTATION [Go to Page]
- 9.1 Requirements of Reporting. The accurate and understandable documentation of the results of testing is absolutely essential to the completion of a testing project and operation of the facility. The points tested, the design requirements, and the t...
- 9.2 Checklists, Spreadsheets, Summaries. The presentation of testing data in an organized form is usually done with spreadsheets. However, other methods are acceptable. (Example: Building and installation inspection tasks can be shown on checklists.)
- 9.3 Test Instrumentation
- 9.4 Distribution . Deficiencies, preliminary data, and the final report are to be distributed in accordance with contractual requirements. (Note: It is advisable to request permission from the appropriate authority before distribution of any document...
- 10. REFERENCES
- INFORMATIVE APPENDIX A—INSTRUCTIONS FOR TESTING AND FOR COMPLETING TEST FORMS [Go to Page]
- A1. INSTRUCTIONS FOR TESTING HUMIDITY CONTROL SYSTEMS
- A2. INSTRUCTIONS FOR TESTING WATER SYSTEMS
- A3. INSTRUCTIONS FOR COMPLETING FORM A (REPORTING ON RELATIVE HUMIDITY DEVICES)
- A4. INSTRUCTIONS FOR COMPLETING FORM B (REPORTING ON WATER-SYSTEM DEVICES)
- A5. INSTRUCTIONS FOR COMPLETING FORM C (REPORTING ON WATER-SYSTEM SWITCHES)
- A6. INSTRUCTIONS FOR COMPLETING FORM D (REPORTING ON HUMIDITY CONTROL SYSTEMS)
- A7. INSTRUCTIONS FOR COMPLETING FORM E (REPORTING ON WATER-SYSTEM CONTROL LOOPS)
- INFORMATIVE APPENDIX B—TUNING PI CONTOLLERS [Go to Page]