MODENA S HE
25
EN
cod. 3541C360 - 04/2012 (Rev. 00)
If the combustion reading is greater than the acceptable value AND the integrity of the complete flue system
and combustion circuit seals have been verified and the inlet gas pressure (and gas rate) have been verified,
proceed as in section " Setting the Air/Gas Ratio valve" pag. 25
.
Setting the Air/Gas Ratio valve
There are two adjustments possible on the air/gas ratio valve, the throttle setting at maximum rate and the offset setting
at minimum rate. If either setting is adjusted the combustion values must be rechecked at both rates.
At Maximum Rate:
1. Adjust the boiler to maximum rate in section 3.3 Test Mode.
2. Wait 10 minutes to allow the boiler to stabilize.
3. Now adjust the
Throttle setting
(fig. 31 - screw
A
) until the CO
2
is at the correct
SETTING LEVEL
(see table 4),
confirm that the CO/CO
2
ratio is within limits.
NOTE:
ADJUST IN STEPS OF
NO MORE THAN 1/8 OF A TURN
AND WAIT 1 MINUTE AFTER EACH ADJUSTMENT
TO ALLOW THE SETTING TO STABILISE.
In the event that the CO
2
setting level with an acceptable CO/CO
2
ratio cannot be obtained please contact the
helpline number.
Should you require any assistance during the set up procedure call our Technical service helpline or
should you
require a service engineer to visit call our service centre at numbers listed on last page of this manual.
At Minimum Rate:
1. Adjust the boiler to minimum output and allow the boiler to stabilize.
2. Now adjust the
offset pressure setting
(fig. 31 - cup
B
) until the CO
2
is at the correct
SETTING LEVEL
(see
table 5), confirm that the CO/CO
2
ratio is within limits.
NOTE: ADJUST IN STEPS OF
NO MORE THAN 1/8 OF A TURN
AND WAIT 1 MINUTE AFTER EACH ADJUSTMENT
TO ALLOW THE SETTING TO STABILISE.
Re-check the Minimum Rate
Turn off the boiler and then turn it back on and put in Test Mode at maximum for 1minute. Reduce to mini-
mum and re-check
the minimum rate output ensuring the CO2 setting level has remained unchanged and confirm that
the CO/CO
2
ratio is within limits.
In the event that the CO
2
setting level with an acceptable CO/CO
2
ratio cannot be obtained please contact the
helpline number.
Should you require any assistance during the set up procedure call our Technical service helpline or
should you
require a service engineer to visit call our service centre at numbers listed on last page of this manual.
fig. 31 - Gas valve
A
Throttle
B
Offset adjustment
NOTE:
In the event that an acceptable setting level
cannot be obtained it will be necessary to change the
Air/Gas Ratio Valve.
A
B
A
Summary of Contents for MODENA S HE
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