Thermostatic Series And Safety Loop - Unigas HTP2000 Installation Manual

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3 Thermostatic series and safety loop

The burner shuts down properly when the thermostatic series (X5-03.1 and X5-03.4 - terminals 3 and 4 of the burner terminal block) opens. In this way,

before shut-down, the burner drives to the minimum load, then the fuel valve will close. The post-purging phase will be performed if set. By re-closing the

thermostatic series, the burner will start-up again.

In the plant other safety devices are provided (levels, pressure switches, thermostats, air damper) . All these contacts are connected in series to the 318-

319 terminals of the burner supply terminal block. When the safety loop closes, the burner is ready to restart. The actuators move to "home position"

(standby position), and if terminals 3-4 are closed the start-up cycle resumes; otherwise the burner enters the standby phase.

In the plant the safety thermostat is provided as well. If this thermostat switches (terminals X3-04.1 e X3-04.2 corresponding to terminals 318 and 319 of

the burner supply terminal block - see below), the system will lead to an immediate burner lockout.

In case of burner designed with automatic pull-out system from the generator, the burner flange end switch is connected to terminalsX3-03.1 e X3-03.2.

If the contact open, the burner automatically shuts down.

NOTE: When the safety loop opens, the burner will immediately turns off, skipping the low flame stage. It's important to distinguish between "safety

loop" and "thermostatic series"

The maximum number of emergency shut-downs is 16. When this number is reached a lockout will occur AZL will show the message: "Open safety

loop".

Following the below route access to the programming levels of the menu:

1st level

2nd level

Params & Display

BurnerControl

3rd level

4th level