Worcester 350 Combi User Manual

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START OF PUMP OVERRUN TEST
NO
With no DEMAND and with p rimary --...
water te mp erature abov e 75'C
(approx.) does the fan operate'
YES
YES
Does the STANDBY in d icator
illumi n ate?
Free the fan if it is stuck or
replace the fan. ..,__ Is there mains supply on the brown
------ - pinoftermina iX 171
NO
__... See Section STANDBY INDICATOR
DOES NOT ill U MINATE .
NO
--... Is th ere less than 2V DC on the red
p in of terminal XS ?
YES
I YES
Replace the ignition board . ..,__ Is there than 39V DC on the orange
__..:..___ _ ____ pi n of terminal XS ?
NO I
Replace the driver board assembly.
NO
NO
Doe s the fan turn off when the
primary temperature drops to 6S'C
(a p prox .)?
__... Is t he re l ess t han 2V DC on the red
pin of terminal XS ?
__... Replace the igniti on b oard.
I YES
End of fan over·run test
Replace the driver board assemb ly.
OVERHEAT PROTECTION TEST
NO
Does the applia n ce shut down if the --... Rep l ace the system overheat
p rimary wa ter flow from the Gas to thermostat.
Water heat exchanger exceeds 100 ' C? ---------
LOW SYSTEM PRESSURE PROTECTION TEST
NO
Does the appliance shut dow n if the --... Replace the low system pressure
primary wa t er pressure drops below switc h.
0.2 bar (3 p. s.i.)? ----- - ---
DOMESTIC HOT WATER OVERHEAT PROTECTION TEST
D oes the burner shut down if the
d omestic hot wa t er temperature
exceeds 90 ' C?
NO
--... Rep l ace the domestic hot wa t er
overheat th ermosta t.
41
R ep lace the driver board assembly.
NO
NO
--... Re move and inspect the cent r al
hea ting sensor. Is it badly scaled up?
I YES
Replace the ce n tral hea ting sensor.

Worcester 350 Combi Specifications

General

Brand	Worcester
Model	350 Combi
Category	Boiler
Language	English