Potterton Isis HE Installation, Operation & Maintenance Manual page 23

SECTION 5
PAGE 20
BOILER MAINTENANCE
It is essential for efficient and trouble free operation
that the boiler plant is regularly maintained. This must
be carried out by qualified and experienced
engineers and in the case of gas fired appliances
attention is drawn to the mandatory requirement of
CORGI (Confederation of Registered Gas Installers)
registration of personnel undertaking work on these
appliances. This facility is available from Potterton
Commercial Division, details are available from
regional offices listed on the back page back of this
manual.
Boilers should be serviced and re-commissioned as a
minimum on an annual basis.
It is strongly advised that a maintenance contract be
entered into with Potterton Commercial Division to
ensure that the boiler/burner unit is correctly and
properly maintained.
WARNING
Isolate the electrical and fuel supplies before
attempting any maintenance work.
Cleaning of Flue Surfaces
The boilers are supplied with a set of cleaning tools
comprising flueway brushes and extension rods for
routine cleaning procedures as detailed in the parts
list. Boilers may require periodic cleaning with
specialist mechanical equipment dependent on boiler
conditions, fuel type, etc.
Cleaning of the boiler requires opening of the door,
removal of the boiler inserts, these should be
removed and re-installed as detailed in Section 4.
Frequency of boiler cleaning varies and is dependent
on site conditions, fuel type, heat load, design of
controls and running conditions.
For the maximum efficiency and economy in running
it is essential that the combustion chamber and
flueway surfaces should be kept clean and free from
deposits.
A layer of deposits 1/16" thick will reduce the heat
transfer through the tube wall by up to 10%.
Not only does this waste fuel but the higher flue gas
temperatures that result will increase the thermal
stress within the boiler and may lead to joint leakage
or in extreme cases section failure.
POTTERTON COMMERCIAL PRODUCTS DIVISION
INSTALLATION, OPERATION & MAINTENANCE MANUAL
Natural gas, manufactured gas & LPG Fired
Boilers
We recommend brushing out of the combustion
chamber and flueways and the removal of the rear
clean out covers to check for deposits in the flue box
twice a year.
Class 'D' Fuel Oil
The boilers should be brushed out thoroughly at least
bi-monthly for 35 second and Class 2, 28 second
during the heating season but more frequent
attention may be necessary dependent on the
operating conditions to prevent the formation of hard
adherent scale on the tube surfaces.
It is essential to ensure that cleaning is carried out
throughout the full length of the flue tube passes and
that the rear clean out covers are taken off to allow
for removal of deposits brushed through into the flue
box.
Should a heavy or tough adherent deposit become
formed, which is too hard for the standard brush to
remove, it may be necessary to either:-
1. Wash out the tubes with water followed by a
thorough brushing – this may have to be
repeated several times.
Or
2. Use a flexible drive rotary tube scaling
machine.
Classes 'E' & 'F' Fuel Oils & Sludge Gas
Maintenance for boilers running on these fuels will be
required at more frequent intervals, possibly on a
weekly basis or even a daily basis dependent on fuel
type and quality.
Boiler Ancillaries
Check the sealing of the boiler door against the front
section. There should be a uniform depression about
3/32" (2mm) deep from the sealing grooves of the
front section in the braiding. If this is not uniform, the
sealing may be adjusted by the locknuts on the hinge
pins – see Fig.8. Make sure the locknuts are fully
tightened after adjustment is complete.
Keep a regular check on the condition of the door
refractory and the infill around the burner draught
tube. If there is any deterioration this must be made
good immediately to prevent damage to the boiler
and burner.
ISIS HE