Technical Information
Page 2 of 3 V1. Aug 2018
Heating System – Flushing
To determine whether the system is completely flushed, take a sample of water from the drain valve and carry out
either or both of the following two tests:
1. Fill the Turbidity Tube to the top mark again (200ppm) and look through the column of water. If the black
concentric circles are visible then the system is sufficiently clean. If the circles are not visible, then further
flushing is required until the circles can be seen. Record the final reading on the Survey Report e.g. <200ppm.
2. Measure the TDS of the water, using the meter supplied. If this value is within 10% of the TDS of the cold mains
water (previously measured) it indicates that the system has been flushed satisfactorily to remove the cleaning
chemical. Record the TDS reading on the Survey Report once a satisfactory reading has been obtained.
Heating System – Post-flushing
Once the final flush has taken place and Sentinel X100 scale and corrosion inhibitor has been added, take a further
system sample and check for correct levels of Sentinel X100 using the Sentinel Test Kit. Once a satisfactory level
has been achieved record this on the Survey Report in the appropriate place.
Finally, return each TRV to its original position, switch on the boiler and allow it to come up to temperature without
resetting the thermostat. The radiators must then be bled as necessary and a further temperature survey of the
radiators carried out as detailed in the Pre-flushing section above. The new temperatures must then be recorded
on the Survey Report in the appropriate place.
Test Equipment Instructions
Turbidity Tube
The Turbidity Tube is an excellent way of assessing the clarity of the system water. It is calibrated along the length
of the tube in terms of parts per million of suspended solids and also turbidity units. The simple process of using
the tube is as follows:
3. Fill the tube to the top line (200ppm) with system water
4. Look through the column of water. If the black concentric circles can be seen then the level of suspended solids
is <200ppm and, for most situations, this would indicate a satisfactory quality of water.
5. If the circles cannot be seen then remove water from the tube until they are visible. At the final water level take
the reading off the side of the tube.
TDS Meter
Operation
1. Remove the probe cap, and then press the power button. The LCD should now show “000”.
2. Dip the probe into the water without exceeding the water level limit.
3. Stir gently until the display stabilises and then remove the meter from the water. (The reading will
automatically hold).
4. Read the value on the display expressed in ppm.
5. To reset the reading when in use, press the power button. The LCD should now show “000”.
6. After measuring, gently shake the meter 2-3 times to remove residual water and then close the probe cap. The
meter will automatically turn off after approximately 40 seconds.
7. To turn the meter off manually, press the power button for 3 seconds.
Calibration
1. Remove the probe cap, and then press the power button. The LCD should now show “000”.
