114
Display message
F19
S i p h o n
s w i t c h
p u m p
o n
9 9 9 , 5
h r s
Reason:
Siphon pressure switch detects high pressure in the flue/siphon
system.
Cause:
There is too much resistance in the flue gas circuit causing high pressure in the heat ex-
changer at the flue gas side.
Corrective action:
Check if the flue gas system is blocked.
Extreme fouling of the heat exchanger also causes the resistance to rise. Check the state
of the heat exchanger and clean if necessary.
Check the flue gas system diameter & length (most likely in a new system).
Cause:
The condensate drain system is blocked. The condensate will build up above the measur-
ing point of the pressure switch and creates a static pressure larger than the measuring
point.
Corrective action:
Check if the condensate drain hose between the heat exchanger and the siphon is open,
so the condensate can flow freely to the siphon.
Check if the siphon is free of debris that might block the condensate flow and clean the
siphon if necessary.
Check the condensate drain hose between the siphon and the condensate drain point in
the external installation. Condensate must be able to flow freely.
Cause:
The condensate drain hose must have an open connection to the external system. If not,
pressure fluctuations in the building drainage system can have effect on the pressure in
the heat exchanger of the boiler.
Corrective action:
Make sure that there is an open connection between the siphon hose and the drainage
system of the building installation. The condensate should flow in the drainage system
through a freely "breathing" connection, so pressure fluctuations of the external drainage
system cannot affect the pressure in the heat exchanger of the boiler.
Cause:
Blockage of the pressure signal hose going to the pressure switch.
Corrective action:
Check the pressure signal hose and clean or replace it if necessary.
Cause:
Bad pressure switch causing a fault signal.
Corrective action:
Replace the pressure switch.
Cause:
Bad wiring/connection in the pressure switch circuit.
Corrective action:
Check for loose wiring/connections in the pressure switch circuit.
Display message
F17
W a t e r
h i g h
l
i m i t
p u m p
o n
9 9 9 , 5
h r s
Reason:
Maximum thermostat exceeds limitation value.
Cause:
The water flow is restricted.
Corrective action:
Check functioning of the pump.
Check/open all valves that might restrict the water flow through the unit.
Check for an external system pump that influences the flow through the unit.
Check if the system resistance exceeds the spare capacity of the unit pump.
