Underfired:
Lazy-burning main flame cone, mushy flame
appearance throughout, smaller flame size
than in Fig. 17.
Overfired:
Increased pilot burner noise, long inner and
outer flame cone towards main burner.
7.7
Periodically:
•
Inspect low water cut-offs, including flushing of float
types (if used).
•
Inspect flow switch (if used).
•
Inspect main burner flame and pilot burner
7.8
Service agency – annually:
Boiler servicing – heat exchanger cleaning
The heat exchanger should be cleaned once a year as
outlined in section 8.3.
Before heating season starts, boiler/burner should be
serviced by a qualified service agency.
7.9
Lighting instructions – (see page 14)
electronic ignition – natural gas
a)
Follow steps outlined on page 14
b)
Ignition will occur at pilot burner. When pilot is
ignited, ionization electrode will prove flame, and
control will open main gas valve. Pilot flame will
then ignite main burner.
Trial for pilot ignition is 15 seconds. If pilot flame is not
established in 15 seconds, control will lock out.
If ignition control locks out then restart by turning power
off, waiting 5 minutes, then turning power back on
again. This can be done by turning the 120V power
supply off, or the on/off switch on the boiler Vitotronic
control. The remote operating control can also be used
to reset the ignition control. Ignition will occur according
to the above procedure.
The Honeywell ignition S8600B control does not require
manual reset on flame failure. The S8600B is standard
equipment.
If it is required to have manual reset on pilot flame failure,
the boiler must be ordered with the RA890F flame
safeguard control (not shown in this manual). Specify
RA890F at the time of ordering for pricing and delivery.
7.10
Vitotronic control
For combination space heating and domestic hot water
consult Viessmann sales representative for control
options and piping diagrams.
If boiler water temperature exceeds 248°F (120°C), the
fixed high limit will be tripped. To reset, use a pointed
object, such as a pencil tip, to push in green button until
an audible click is heard.
Note: If the operating limit is set at the maximum setting
194°F (90°C), the pump must run after burner shut-
down to prevent a boiler temperature rise tripping the
manual reset high limit. This can be avoided by setting
the pump aquastat 18°F (10°C) below the operating
limit setting.
8.0
Maintenance
WARNING: Always switch off and disconnect electricity
supply and close the manual gas shut-off valve before
carrying out service work or replacement of failed
components.
8.1
General
Full maintenance should be undertaken not less than once
per year. After servicing work has been completed or any
component replaced, the boiler must be fully tested.
8.2
Main burner removal (see Figs. 16, 18, 19)
Main burner tubes are removed individually from the
manifold. They are located at the back by a pin, and at
the manifold by the gas orifice and an offset pin, and
retained by a Phillips screw.
a)
Ensure manual gas shut-off valve is in the closed
position and turn off all electric power to the boiler.
b)
Remove the front door of the casing and the lower
front panel by pulling forward.
c)
Remove the Phillips screw M5 x 8 securing each
burner tube to the burner manifold and remove the
burners.
d)
Using a stiff brush, not a wire brush, brush the
burners to dislodge any accumulated deposits.
Inspect the burners to ensure that they are clean.
e)
Examine the orifices and if damaged or
deteriorated, replace with new ones of the correct
size and marking (see Table 1 below). If necessary,
clean the orifices. Do not broach with wire.
f)
Re-assemble the orifices and burners in the
reverse order to that above. To install burner tubes,
insert the burner tube facing up from under the gas
manifold, and slide along guide on bottom edge of
boiler casting. When burner support pin engages in
locating hole at the back of the casting, align burner
tube with orifice, and pull tube back over the orifice
and locating pin on manifold; fasten with Phillips
screw. If the heat exchanger is to be cleaned,
replace burner tubes only after cleaning is completed.
Table 1: GAS ORIFICES
13
Altitude above
Natural Gas
L.P. Gas
sea level
ømm
ømm
0 – 2000 ft.
4.30
2.50
2000 – 4500 ft.
4.10
2.30
2000 – 7000 ft.
4.10
2.30
