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Pressurisation values should be included in the range given in the table of technical specifications.
WARNING
The differential temperature between boiler flow and return must not exceed 15°C in order to prevent
thermal shock to the boiler structures. The temperature of the return water must be above 55°C in
order to protect the boiler from corrosion due to condensation of the flue gases on cold surfaces; for
this purpose it is useful to install a 3 or 4-way mixing valve. The guarantee does not cover damages
caused by condensate.
A recirculation pump (anticondensate pump) must be installed to mix the cold returns. This pump
should have a minimum flow rate equal to approximately 5 m
3
/h or equal to 1/3 or 1/4 of the heating
system pump flow rate.
It is necessary to keep the burner switch always switched on in order to maintain water temperature equal
approximately to the value set through the thermostat.
If the flue gas seal is poor in the front part of the boiler (manhole and burner plate) or the back part
(smokebox), the closing tie rods of the individual parts must be adjusted; if this is not sufficient, the seals
must be replaced.
CAUTION
Do not open the manhole and do not remove the smokebox while the burner is working. Always wait
few minutes after the burner has been switched off until the insulating parts are cooler
.
6.2 CLEANING AND SERVICING
Close fuel supply and disconnect the electrical mains before starting any cleaning and servicing operations.
As economic running depends on cleaning of the exchange surfaces and regulation of the burner, the follow-
ing operations should be performed:
- Clean the tube bundle and turbolators with the appropriate tube-brush every month for heavy oil-fired
boilers, every three months for gas oil-fired boilers and once a year for gas-fired boilers. Cleaning sched-
ule depends on plant features.
Quick cleaning can be performed by opening the front manhole only, taking the turnolators out and cleaning
the tubes with a tube-brush. For more thorough cleaning, the smokebox must be removed to eliminated car-
bon deposits from the rear side.
-
Have the burner calibration checked by professionally qualified personnel;
- Have the water circulating in the system analysed and provide for adequate treatment to avoid the for-
mation of scale which initially reduces the efficiency of the boiler and in the long term will permanently
damage it, making it unserviceable;
- Check that the refractory castings in contact with the flue gases are in perfect condition and if not, re-
place them;
-
Periodically check the efficiency of the system regulation and safety instruments.
