A Solar Domestic Hot Water (SDHW) Heating
Interactive Troubleshooting Program, SDHW-PROB
The purpose of this work has been to develop a working tool for the beginning to intermediate solar service person or homeowner with a personal computer who wishes to troubleshoot SDHW systems. The homeowner, however, may be somewhat limited because some paths of questioning may require him or her to make some tests with tools he or she may not normally own. Such tests are primarily in the area of testing a sensor’s resistance or measuring for the presence of 120 volt AC power.
Due to the great number of variations of installed SDHW system configurations, the domain of SDHW-PROB has been limited to 120 volt, active, flat plate collector, two tank systems. The heat collection loops can be either recirculation, drain down, drain back, or closed-loop-antifreeze. SDHW-PROB can work with either in-tank or external heat exchangers. SDHW-PROB has the capability to diagnose about 100 (see table below) of the more common operational problems encountered in the SDHW service business.
Some of the tests that are needed in order to answer the troubleshooting questions require that you access energized 120 volt wires. If you do not have the knowledge to work with an electrically energized system or if you don't feel comfortable in doing so, then go no further. I do not assume any responsibility for anyone hurting themselves or damaging any equipment by attempting the tests outlined in this program. So, you should not attempt such tests without knowing fully what you are doing and being familiar with the system and test equipment.
Although this program is designed primarily to diagnose operational problems, several design problems that result in operational problems have also been included.
Certainly, more problems could be included as they are encountered. A program such as this is never complete. New problems are always only a service call away.
SDHW-PROB is available for your use online at no charge. If there appears to be enough interest in this program, I'll look into the possibility of making it available on a CD for a nominal cost.
Problem solutions contained within SDHW-PROB
| General Cause of the Problem | Specific Cause of the Problem |
COLLECTOR LOOP
PUMP IS NOT
PUMPING |
POWER CORD TO COLLECTOR LOOP OR DHW LOOP PUMP POWER CORD CONNECTION TO COLLECTOR LOOP OR DHW LOOP PUMP COLLECTOR LOOP OR DHW LOOP PUMP MOTOR WINDING COLLECTOR LOOP OR DHW LOOP PUMP STARTING CAPACITOR COLLECTOR LOOP OR DHW LOOP PUMP ROTOR COLLECTOR LOOP OR DHW LOOP PUMP IMPELLER COLLECTOR LOOP OR DHW LOOP BINDING IMPELLER COLLECTOR LOOP OR DHW LOOP PUMP BEARING COLLECTOR LOOP OR DHW LOOP PUMP CAVITATION COLLECTOR LOOP OR DHW LOOP PUMP ROTOR FROZEN DUE TO MINERALIZATION IMPROPER VALVE SETTING CORROSION AT ONE OR MORE FITTINGS HEAT EXCHANGER FLOW RESTRICTION CLOGGED STRAINER |
| CONTROLS PROBLEM | ON-OFF-AUTOMATIC
SWITCH POSITION CONTROLLER OUTPUT DEVICE SHORTED CONTROLLER OUTPUT DEVICE OPENED CHATTERING RELAY HIGH LIMIT AND/OR FREEZE PROTECTION ENABLE JUMPERS OR SWITCHES IN WRONG POSITION DEFECTIVE CONTROLLER FREEZE SENSOR FREEZE SENSOR WIRING FREEZE SENSOR WIRING TERMINATION HIGH LIMIT SENSOR HIGH LIMIT SENSOR WIRING HIGH LIMIT SENSOR WIRING TERMINATION COLLECTOR COMPARISON SENSOR COLLECTOR COMPARISON SENSOR WIRING COLLECTOR COMPARISON SENSOR WIRING TERMINATION STORAGE COMPARISON SENSOR STORAGE COMPARISON SENSOR WIRING STORAGE COMPARISON SENSOR WIRING TERMINATION |
| DHW NOT BEING HEATED | THERMOCOUPLE PILOT LIGHT GAS VALVE GAS VALVE THERMOSTAT ELECTRIC HEATER POWER SOURCE ELECTRIC HEATER THERMOSTAT ELECTRIC HEATER ELEMENT |
| EXPANSION TANK PROBLEM | DIAPHRAGM SCHRADER VALVE SIZING AIR IN PIPING PRESSURE GAUGE HEAT COLLECTION LOOP LEAK SYSTEM CHARGED TO TOO LOW OF A PRESSURE |
| PANEL PROBLEM | FRAME DAMAGE |
| LEAKING PIPE OR PIPE FITTING | THREADED FITTING SOLDERED FITTING CORRODED THROUGH PIPE CLAMPED FITTING FROZEN PIPE PHYSICAL ABUSE INSTALLATION / MFG. DEFECT WRONG PIPING MATERIAL EXCESSIVE MECHANICAL STRESS |
| LEAKING PUMP | PUMP / PIPING CONNECTION PUMP BODY |
| UNBALANCED FLOW THROUGH PANELS | PANEL AIR LOCK CLOGGED AIR VENT VALVE PANEL FLOW RESTRICTION IMPROPERLY PLUMBED PANELS |
| POWER SOURCE PROBLEM | CIRCUIT BREAKER IN OFF
POSITION BRANCH CIRCUIT OVERLOADED SHORTED PUMP OR VALVE SHORTED CONTROLLER OPEN POWER SUPPLY CORD OPEN IN BUILDING WIRING DEFECTIVE CIRCUIT BREAKER INTERMITTENT OVERLOAD |
| TEMPERING VALVE PROBLEM | HEAT SENSING ELEMENT DEBRIS IN VALVE PORTS |
| DHW LOOP LEAK | VALVE STEM OR WASHER
LEAK LEAKING RELIEF VALVE IMPROPERLY INSTALLED CHECK VALVE DEFECTIVE RELIEF VALVE |
| RUPTURED PANEL - FAILURE TO DRAIN | IMPROPERLY PLUMBED PANELS FROZEN DRAIN VALVE DRAIN LINE DEBRIS OR FROST IN VACUUM BREAKER DRAIN VALVE MALFUNCTION |
| OTHER | FREEZE DAMAGE PRESSURE GAUGE IMPROPERLY ADJUSTED RELIEF VALVE LEAKING CHECK VALVE STUCK OPEN CHECK VALVE DEFECTIVE THERMOMETER DEGRADED PANEL MATERIAL FROZEN PANEL ACIDIC FLUID - CORROSION INSTALLATION / MFG. DEFECT OVERFILLED DRAINBACK TANK CLOSED VALVE DRAINBACK TANK LOW ON WATER PUMP SIZING |
So, let's get started. This is a program to assist you in troubleshooting an operating problem with an active solar domestic hot water (SDHW) system. The systems are limited to 120 volt AC, two tank recirculation, drain down, drain back, and closed loop antifreeze systems that use flat plate collectors. Do you want more information on how to use SDHW-PROB before starting a consultation? |
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