Calibration Of Thermal Relay; Current To The Uv Photocell - Riello RLS 100 Installation, Use And Maintenance Instructions

6.3

Calibration of thermal relay

This is required to avoid motor burn-out in the event of a signifi-
cant increase in power absorption caused by a missing phase.
• If the motor is star-powered, 400 V, the cursor should be po-
sitioned to "MIN".
• If the motor is delta-powered, 230 V, the cursor should be po-
sitioned to "MAX".
Even if the scale of the thermal cut-out does not include rated mo-
tor absorption at 400 V, protection is still ensured in any case.
NOTE
 The burners leaves the factory preset for 400 V power sup-
ply. If 230 V power supply is used, change the fan motor
connection from star to delta and change the setting of the
thermal cut-out as well.
 The burners have been type- approved for intermittent oper-
ation. This means they should compulsorily be stopped at
least once every 24 hours to enable the control box to check
its own efficiency at start-up. Burner halts are normally pro-
vided for automatically by the boiler load control system.
If this is not the case, a time switch should be fitted in series
to IN to provide for burner shut-down at least once every 24
hours.
6.4

Current to the UV photocell

Min value for a good work: 70 µA.
If the value is lower, it can depend on:
– exhausted photocell
– low current (lower than 187 V)
– bad regulation of the burner
In order to measure the current, use a microammeter of 100 µA
c.c., connected to the photocell, as in the scheme, with a capac-
itor of 100 mF - 1V c.c. at the same level of the instrument.
See Fig. 28.
20033295
Electrical system
 The burners are factory set for two-stage operation and must
therefore be connected to control device TR. Alternatively, if
single stage operation is required, instead of control device
TR install a jumper lead between terminals 6 and 7 of the
terminal strip.
WARNING
D1143
26
GB
D867
– Do not invert the neutral with the phase wire
in the electricity supply line. Any inversion
would cause a lockout due to firing failure.
– Only use original spare parts to replace the
components.
Fig. 27
Fig. 28