10.3.6 Checking the PS air pressure differential switch
Checking the air pressure differential side
1. Switch off the boiler.
2. Disconnect the silicon hose on the + side (P1) of the air pressure dif
ferential switch.
3. Take a large plastic syringe or bellows and connect a T piece with a
hose connected.
4. Connect the + side of the air pressure differential switch to one end
of the T piece with a hose.
5. On the other end of the T piece, connect the + side of a pressure
gauge.
6. Turn on the boiler
7. Push the syringe or bellows in very slowly until the boiler goes into
failure mode.
8. Make a note of the pressure indicated by the pressure gauge at that
point. A switch pressure of between 5.5 and 6.5 mbar is fine. A low
er or higher switch pressure indicates a problem with the air pres
sure differential switch.
9. After taking a measurement, detach the silicon hose from the T
piece on the + side and reconnect the hose that was previously re
moved.
Caution
Please note: The + side (P1) is the rear connector nipple of the air
pressure differential switch.
10. Remove any soiling from all connection points for hoses and the air
pressure differential switch.
11. Check the condition and tightness of the hoses of the air pressure
differential switch. Replace the hoses if necessary.
Checking the air pressure differential switch – side
1. Disconnect the short, coloured silicon hose on the – side (P2) of the
air pressure differential switch.
2. Connect the – side of the air pressure differential switch to one end
of the T piece with a hose.
3. Pull out the syringe until the boiler goes into failure mode.
4. Make a note of the pressure indicated by the pressure gauge at that
point.
A switch pressure of between - 5.5 and - 6.5 mbar is fine. A lower
or higher switch pressure indicates a problem with the air pressure
differential switch.
5. After taking a measurement, detach the silicon hose from the T-
piece on the – side and reconnect the coloured hose that was previ
ously removed.
6. Remove any soiling from all connection points for hoses and the air
pressure differential switch.
7. Check the condition and tightness of the hoses of the air pressure
differential switch.
Replace the hoses if necessary.
Fig.45
Check the air pressure differential
side
AD-0000135-03
SLOW
(+)
7
3
5
X mbar
.....
... m
bar
8
5,5 ...6,5 mbar
6
P
2
(-)
P
1
(+)
2
4
1
Fig.46
– side of the air pressure differential
switch
AD-0001076-01
SLOW
3
X mbar
.....
... m
bar
4
-5.5 mbar....-6,5
(+)
P
1
(+)
1
2
P
2
(-)
10 Maintenance
58
7625116 - v.04 - 17012017
