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© Baxi Heating UK Ltd 2011
17.0 Fault Finding
CONDENSATE PUMP
Lights
On
*
*
NO
NO
Reset boiler
and add approx. 1 litre
tap water to the condensate
system via the flue or
sample point
YES
Mechanical fault
on float, linkage or switch.
Mechanical fault on pump
or impellor.
Does the
pump motor run as
the condensate level
rises ?
As the pump motor runs
does the condensate flow to
drain ?
Is
condensate flow
rate at least 1.8 l/min and run
time less than 3
minutes ?
YES
If fault cannot be rectified
replace level switch or
pump assembly.
YES
5Vdc at A ?
No - replace PCB
5Vdc at B ? No - check wiring.
240V across C & D ?
No - replace level
switch
NO
Condensate pump
outlet back check valve
blocked or seized shut.
If fault cannot be rectified
replace pump assembly.
YES
NO
Condensate pipe
blocked or kinked, or outlet
blocked or frozen
at drain.
Rectify fault, replacing pipe
if necessary.
YES
NO
Condensate pipe
has high resistance - too long
or restricted, head greater than
3 metres.
Rectify fault, replacing or
re - routing pipe
if necessary.
YES
NO
Pump motor or
impellor worn - replace
pump assembly
Does
pump motor stop
as level in reservoir
falls ?
NO
Mechanical fault on
float, linkage or level switch.
After 3 mins boiler
will lock out.
YES
YES
YES
Operation correct
If fault cannot be rectified
replace level switch or
pump assembly.
Lights
On Off On
Condensate pump over level
switch activated - pump
reservoir level too high
resulting in ignition lockout.
Condensate pump level switch
activated for longer than 3
minutes - boiler locks out.
Boiler will try to relight 4 times
in 5 minutes.
PCB
Condensate Pump
Motor
Condensate
Over-Level Switch
Condensate
Level Switch
LN
gy
gy
Condensate Pump Assembly
‘A’
‘D’
‘B’
‘C’
Go to diagram for
connections to check
Is motor
resistance across C & D
approx. 40 ohms ?
No - replace pump
assembly