Combustion Testing And Adjustment; Check Flame & Combustion With Instruments; Throttle Screw Location - Weil-McLain ULTRA ULTRA-105 Service Manual

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GAS FIRED WATER BOILER SERIES

Combustion testing and adjustment

DO NOT PROCEED WITHOUT COMBUSTION TEST EQUIPMENT
The combustion testing and adjustment procedures on this and the following pages are intended only for a quali-
fied technician, using combustion test equipment. Failure to use combustion test equipment to verify adjustments
could result in severe personal injury, death or substantial property damage.
When is adjustment required?
Ultra boilers do not typically require field adjustment. However,
it may be necessary to verify and possibly adjust the combustion
settings of the boiler. A calibrated combustion analyzer is neces-
sary to measure the Ultra's combustion settings and adjust, if
necessary. The information below is to assist in this adjustment
for the Ultra boiler.
A boiler that is out of adjustment may have some or all of the
following symptoms: difficulty igniting, poor stability at low fire,
combustion noise, and/or above normal carbon monoxide read-
ings. If any of these symptoms are present the boiler needs to be
thoroughly inspected to rule out any possible causes due to compo-
nents other than the gas valve venturi assembly, such as connections
Check flame & combustion with instruments
1. Initiate a call for heat on one of the heat demand inputs.
2. Press and hold both the Ultra control panel "Mode" and "+" but-
tons simultaneously until "H" appears.
3. The "H" in the first digit of the display means the boiler will operate
at high fire when the blower speed reaches maximum.
4. Look at the flame through the flame inspection window. The high
fire flame should be blue and should be stable. The burner surface
should be covered with orange dots.
5. Remove the flue temperature sensor from the flue pipe and in-
sert a combustion test probe., using a calibrated combustion test
instrument.
6. Test for CO (or O ) and for CO. The CO
2 2
1.0% of the values listed in Figure 24, page 40.
a. If results are acceptable, proceed to step
b. IF NOT, follow the instructions under
ment procedure", page 40, to set the throttle screw position.
See WARNING below.
If combustion at either high or low fire is outside
the range given in Figure 24, page 40, follow the
procedure given on page 40 for adjusting the throttle
screw on the venturi. If throttle screw adjustment
does not correct the problem, then shut down the
boiler and contact your local Weil-McLain repre-
sentative. Throttle screw adjustment must be done
only by a qualified technician, using calibrated test
instruments. Failure to comply could result in severe
personal injury, death or substantial property dam-
age.
38
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1 & 2
or venting configuration. Follow the Troubleshooting procedures
in this guide to check for possible causes before proceeding with
combustion adjustment.
If all the other items are ruled out the following instructions may
be used to adjust the venturi in the field.
The venturi is the device attached to the gas valve that controls the
mixture of gas and air entering the blower. The throttle screw is the
only adjustment on the venturi. This adjustment changes the size of
the passage which gas flows into the venturi. This adjustment will
be referred to as the throttle adjustment. This is the only adjust-
ment that is made to adjust air-fuel ratio. Follow the instructions
in the following pages if adjustment is required.
values must be within
2
7.
"Throttle screw adjust-
Part number 550-100-029/0810