Keston Thermomatic RSM20/FB, Installation & Servicing Instructions Manual, Page: 28 / 46

Page 28
Fig. 7.7. CONDITION 7.
Is the heating f rom radiators
sufficient?
Is the boiler htg regulatory
thermostat (HT) at maximum?
Set HT at
maximum.
Faulty ST replace it.
Is the boiler undersized?
Thermostat and thermometer
bulbs wrongly fitted into the
respective sheathings on the
boiler. Insert the bulbs into the
sheathing according to the
draw ing.
Is gas pressure right?
Replace the thermometer
/ w ater gauge.
Dirty Heat exchanger?
Do the thermostats opertate? Do the
thermometer show a w rong temperature? (
the above may happen w hen the thermostat
probes are removed for servicing and
w rongly fitted into the respective
sheathings.)
Restore 1 bar of pressure in
the boiler and in the heating
system (at cold)
No
Yes
FWith the burner alight, check that
the gas pressure at valve outlet (tap
6) is right. Adjust gas pressure
acting on screw 3 af ter having
removed the closing cap. (see Fig
5.2)
Check the heat
requirement.
Faulty boiler htg regulatory
thermostat (HT)?
Replace HT
Insufficient w ater content of the boiler
or of the htg system.
Does the safety thermostat (ST) cut
out below 90ºC?
A complete maintenance
is necessary.
The boiler is w orking. Does the boiler
stop at the temperature set by HT?
Faulty thermometer
Yes
Yes
Yes
Yes
No
No
No
Yes
No
No
No
No
No
Yes
Yes
Yes
Yes