29
D.H.W. arrives very hot but at low flow rate.
D.H.W. taps run neither hot water nor cold.
D.H.W. potentiometer or heating
potentiometer fails to regulate properly.
Boiler is noisy or heat exchanger
makes a sizzling sound.
Boiler safety valve keeps tripping.
Radiators fail to heat up in winter.
Main burner burns badly: flames too
high, too yellow.
Smell of unburnt gases.
Boiler operates but does not increase
temperature.
In the “MURELLE BF CE” vers., with
switch ON, fan fails to turn at min speed.
– Unscrew completely the screw (2, Fig. 28) of the pres-
sure switch valve.
– Check that the filter (4, Fig. 28) on the pressure switch
valve inlet is clean.
– Mains water charge pressure is too low; install water-
lift system to provide adequate static head.
– Exchanger or D.H.W. outlet pipe obstructed by lime
deposits; remove encrustations.
– Check that the sensor in question is in contact with the
pipe; use silicone paste to improve sensitivity.
– The sensor in question is faulty; replace.
– Check whether circulation pump P is obstructed; if
necessary clear it out.
– Unclog impeller of circulation pump, clearing away
any impurities or sediments.
– Circulation pump is burnt out or has a lower rpm than
required; replace.
– Check boiler output is adequate for actual needs of
heating system.
– Check charge cock is closed. If it doesn’t close pro-
perly, replace.
– Check system cold charge pressure is not too high;
keep to recommended values.
– Check whether safety valve is out of calibration; if
necessary, replace.
– Check whether the vessel is sufficiently capacious to
contain the water for the system.
– Check preloading pressure of expansion vessel.
– Replace expansion vessel if faulty.
– “Summer/Winter” switch is on “Summer”; switch to
“Winter”.
– Room temp. thermostat TA is set too low or needs
replacing because faulty.
– Electrical connections of room temp. thermostat TA
are wrong.
– Microswitch of pressure switch valve is faulty; replace.
– Check that pressure of burner gas is regular.
– Check burners are clean.
– Check coaxial assembly has been installed correctly
(
“BF”
version)
– Check boiler is properly clean.
– Check draught is sufficient.
– Check gas consumption is not too high.
– Check gas consumption is not lower than it should be.
– Check boiler is clean.
– Check boiler is sized in proportion to system.
– Check electrical connections and whether electric
power is arriving.
