Spirax Sarco DP27T Installation And Maintenance Instructions Manual page 18

4.2 To set the temperature
1. Check that the temperature scale can be easily seen.
If it is fitted in a confined space facing a wall for example the control head may be
repositioned to enable the scale to be more easily read as follows:-
Undo the three screws. The control head may now be turned through 120° or 240° and
the screws tightened up.
2. By turning the knurled knob, set the scale opposite the pointer to the temperature at
which it is desired to control. (Where it is essential that this temperature be not exceeded
it is advisable to set the control initially some 6 °C lower and bring the plant up to
temperature slowly).
3. Put the plant in operation in the normal way allow 30 minutes for it to settle down, then
check the temperature against a reliable thermometer - this check reading should be
taken as close to the control point as possible to ensure that both the thermometer and
the sensor bulb are sensing similar conditions.
4. Compare the thermometer reading with scale reading on the temperature control.
5. This may be found to differ by a few degrees and if precise control is required can be
adjusted by resetting the pointer as follows:
6. Holding the control head tightly onto the pilot valve housing - slacken the three screws,
just sufficiently to enable the pointer to be moved to the right or left until the temperature
indicated on the scale corresponds with the actual temperature as shown on the sensor.
Whilst making this adjustment it is essential to hold the control head tightly onto the
pilot valve housing otherwise not only will movement of the pointer be difficult but
allowing the head to lift will open the pilot valve.
7. Tighten the three screws.
8. The adjustment knob may now be reset to the required temperature. Adjustments to
raise or lower the temperature may be freely made without damage to the control system.
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