Status Code Displayed
Possible Causes / Description
S0 or S30
External controls not calling for heat
- Check settings of all external heating controls.
If no external controls fitted, ensure terminals 3 & 4
of the boiler terminal strip are linked.
S4 or S7
Initially check that the boiler is not in the anti-cycling
Note: Under normal and
economiser mode
correct operation, status
- override by turning boiler central heating control
code S4 will be displayed
to the "Hot Water only" position and back to the
until the boiler reaches
"Central Heating and Hot Water" position. Check
the set temperature.
that maximum radiator temperature is set to
The faults shown here
between 7-9.
are only to be
1. Lack of primary water flow to heating system.
suspected if the
- check central heating service valves are fully
radiators are not being
open
heated correctly;
- check heating system is correctly filled and
vented of air
2. Diverter valve not switching to CH position.
- check pump is operating correctly
- check positive pressure tube from pump to
diverter valve is clear
- if all above checks satisfactory, replace diverter
valve (see Section 7.17).
S10 or S14
1. DHW microswitch on water section defective
- check or replace microswitch (see Section 7.20)
2. Water section stuck in DHW position
- repair/replace water section (see Section 7.19)
63
8.4.3 Fault Diagnosis using
boiler Status Mode:
Central Heating
Operation
Symptom: radiators not getting hot.
