DXR Drainback
Page 24
The table below lists some of the possible problems, their cause, and their remedy. System owners are advised to
contact the installer whenever a remedy requires some type of in-depth interaction with the solar system.
PROBLEM
POSSIBLE CAUSE
REMEDY
Insufficient Hot Water
Insufficient Solar Energy
Back up source malfunction
Excessive hot water consumption
Check system size, location & orientation
Check / Replace
Reduce consumption
Pump does not start
Controller switch in “Off” position
Controller unplugged or blown fuse
Defective sensor
Turn to “Auto”
Return power to controller or replace fuse
Replace sensor
Pump runs continuously
Controller in “On” position
Defective sensor
Turn to “Auto”
Replace sensor
Pump operates but no fluid
Flows through the
collectors
Flow tubes clogged
Loss of fluid in drainback system
Flush collector tubing
Cool system, locate air leak, refill properly
No water
Isolation Valve closed
Open valve
System leaks
Pipe burst due to freezing or defective joint
Defective seals or piping
Repair or replace
Check pipe insulation
Repair or replace
System does not drain
Collector installed at incorrect angle
Piping insufficiently sloped for draining
Supply and return lines reversed
Change so draining can occur
Check and ensure that piping slopes ¼”/ft
Switch lines
OTHER PROBLEMS
A noisy pump is an indication of worn bearings, obstruction, loss of prime or cavitation. As a rule of thumb, an 8-
20° temperature gain should be expected across a collector, in bright sun, at the proper flow rate. Collectors should
warm (not hot) to the touch.
MAINTENANCE
DRAINBACK MAINTENANCE
Maintenance of a drainback system is minimal. The water heater should be partially purged every 6 months to allow
minerals to be removed preventing scale build up (this is recommended for all water heaters).
The collector glass should be kept clean for best system performance. Rain water will usually suffice, but a garden
hose can be used during dry, dusty weather.
ROUTINE MAINTENANCE
In areas of infrequent rain the collector glazing should be visually inspected on a periodic basis (once a quarter) and
cleaned with a hose if necessary.
The water level in the drainback reservoir should be checked bi-annually. The solar loop includes a fill / drain valve
at the lowest elevation of the pipe work to insure the complete draining of the solar loop if required. With the system
off, make sure that the water level in the sight glass at the drainback reservoir is filled to within ¼” of the top of the
sight glass. If not, follow the instructions in “Filling the Drainback Reservoir”.
