FAULT FINDING
FAULT FINDING FAULT FINDING FAULT FINDING FAULT FINDING FAULT FINDING
Solar Thermal - Installation and Servicing
55
FAULT FINDING
NO FLOW SOLAR PRIMARY CIRCUIT
POSSIBLE CAUSES ACTION
System in “stagnation” Check st. limit at max
Airlock in circuit Purge air
Manometer on low pressure Rell and manually operate Differential Temperature Controller (DTC)
Faulty check valve Check open and if necessary, replace
Steam escaped from AAV Manual isolate AAV and rell. Check expansion vessel
Fluid exhaust from SRV Check expansion vessel, SRV and rell
Faulty or blocked pump Free, clean and if necessary, replace
Frost damage to collector Replace collector and re-commission circuit
Blocked circuit Check for degraded old antifreeze blockage or limescale blockage
PT1000 sensors loose Relocate sensors
Faulty DTC See below
LOW PERFORMANCE OF SOLAR SYSTEM
POSSIBLE CAUSES ACTION
Faulty DTC/system settings Check delta T
on and delta Toff settings, owrate and pump speed control. Also check
functions ON/OFF and DTC on auto.
Faulty PT1000 sensors Check sensor location and check electrical resistance to temperature
(see table in Frame 50).
Faulty pump Check pump is rotating. Check valves open and pump speed correctly set.
Restriction in circuit Check circuit components and for old antifreeze/limescale restriction in pipes.
Inadequate air removal Purge air.
Loss insulation Re-attach insulation.
Boiler primary circuit providing too
much heat
Reset central heating timeclock to give solar system more cylinder water to heat
WATER TOO HOT AT POINTS OF USE
POSSIBLE CAUSES ACTION
Incorrectly set DTC Check st. limit on DTC
Incorrectly set TMV Check output temperature from TMV
Faulty boiler primary circuit Check out boiler primary circuit for faults
FAULTY DTC
POSSIBLE CAUSES ACTION
No LCD display No power supply, check fuse and 230 V
LCD says Short circuit T1/T2 Check relevant sensor for short circuit
LCD says Interruption T1/T2 Check relevant sensor for circuit break
207786-2.indd 58 16/02/2012 11:26:31
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