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8
There must be a link
between High Voltage
terminals 1 & 6 and high
voltage termnials 3 & 6.
Make sure both links are
present
MAF STAT CONNECTED NOT CALLING FOR HEAT (BOILER NOT FIRING) WHEN MAF STAT ON MAXIMUM
NO
YES
YES
NO
NO
YES
YES
YES
NO
YES
NO
NO
NO
NO
YES
YES
NO
Is there 230 ~ 250VAC across High Voltage terminals 2 & 4?
Is there 230 ~ 250VAC across High Voltage terminals 1 & 2?
Measure DC voltage (5.1V DC Max.) across
Low Voltage
terminals 3 & 4
Is measured voltage greater
than 4.7V
Is measured resistance
greater than 11K?
Is measured voltage greater
than 4.7V
Check pipe sensor and
connections. If sound, isolate
from mains & measure
resistance across plug J2 pins
5 & 6
Is measured voltage greater than 4.19V?
Is there an external clock fitted?
Measure DC voltage (5.1V DC
Max.) across
Low Voltage
terminals 5 & 6
Check black wire of MAF stat
goes to
Low Voltage
terminal 3
and red wire of MAF stat goes
to low voltage terminal 4. Ensure
all connections are sound
Check clock is on & measure
output
Check for live supply into clock.
Repace clock if live is present
Is 230 ~ 250VAC present?
Check harness connections
to PCB. If all OK Replace
PCB
Remove MAF stat connections
and link
Low Voltage
terminals
TPV & 3. Is there 230 ~ 250VAC
across High Voltage terminals
2 & 4?
Open circuit between clock
out & High Voltage terminal
block 1
Unit mains
supply is
missing.
Check spur
e.g. fuse is
intact
Check
connections
to high
voltage
terminals
2 & 3
Problem with switched live output going from High Voltage terminal 3
to switch live of boiler
Is there 230 ~ 250VAC across High Voltage terminals 2 & 3?
14. CIRCUIT
DIAGRAM
14. FAULT
FINDING
FIGURE 4. AQUAIR S CIRCUIT DIAGRAM
LINK TO SET
FAN SPEED MIN.
LINK FOR SUMMER
VENT OR TO SET
FAN SPEED MAX.
VOLT FREE
DIGITAL STAT
MAF STAT
PIPE SENSOR TEST
OPTIONAL JUMPER
(SEE INSTRUCTIONS)
REMOVE LINK IF
CLOCK OR
SWITCHED LIVE
IS CONNECTED
MAINS
EARTH
LINK TO TEST
DEMAND
HIGH VOLTAGE
TERMINAL
LOW VOLTAGE
TERMINAL
PIPE SENSOR
FAN
PCB
COLOUR CODE
bn
BROWN
bl
BLUE
bk
BLACK
g/y
GREEN/YELLOW
r
RED
w
WHITE
or
ORANGE
y
YELLOW
