STIEBEL ELTRON SOM 8 PLUS - Page 77

77
Pump is overheated, but no heat transfer from the collector to the store, ow
and return have the same temperature; perhaps also bubbling in the lines.
Air or gas bubbles in the system?
no yes
Is the collector circuit blocked at
the dirt trap?
yes
Clean dirt trap
Pump starts for a short moment, switches o, switches on again, etc.
Temperature dierence at the
controller too small?
no yes
Wrong position of collector
sensors?
yes
Change ∆Ton and ∆To
correspondingly.
no
no OK
Pump starts up very late.
The temperature dirence between store and collector increases enor-
mously during operation; the collector circuit cannot dissipate the heat.
Collector circuit pump
defective?
no yes
Heat exchanger calcied?
yes
Check / replace it
Decalcify it
no
Heat exchanger blocked?
yes
no
Clean it
Heat exchanger too small?
yes
Change ∆Ton and
∆To correspondingly.
Switch-on temperature die-
rence ∆Ton too large?
no yes
Vent the system; increase the
system pressure to a static pri-
mary pressure of at least plus
0.5 bar (7.25 psi); if necessary
continue to increase pressure;
switch the pump o and on
for a short time.
Plausibility control of
the option tube collec-
tor special function
Mount the collector sensor at
solar ow (warmest collector
output); use immersion sleeve
of the respective collector.
Replace with correctly
sized one.
Non-ideal position of the
collector sensor (e.g. atscrew
sensor instead of sensor in
immersion sleeves).
yes
Activate tube collector
function if necessary.
o.k.
295931-36390-8667 SOM 8 plus_en.indb 77 20.10.2011 13:14:59