21
Immersion or strap-on sensors
Immersion probes installation
Sensors must be installed on the stretch of pipe in which fluid circula-
tes all the time.
The rigid stem (sensing element doing the measuring) must be inser-
ted by at least 75mm and must face the direction of flow.
Recommended locations: on a bend or on a straight stretch of pipe
but tilted by 45° and against the flow of fluid.
Protect them to prevent water from infiltrating (dripping gates, conden-
sation from pipes etc.) .
Installing QAD2.. strap-on sensors
Make sure fluid is circulating in the chosen location.
Eliminate insulation and paintwork (including rust inhibitor) on a min.
100mm length of pipe.
Sensors come with straps for pipes up to 100 mm in diameter .
Placing the probes (QAD22.../QAE21.../QAP21.../RCA...)
With pumps on outlet
with 3 ways valves / with 4 ways valves
Panel system / burner control
With pumps on return
with 3 ways valves / with 4 ways valves
Strap-on or immersion sensors?
QAD2.. strap-on sensors
Advantages :
z 10 sec. time constant
z Installed with system running (no plumbing work)
z Installation can be changed easily if it proves incorrect
ПLimits:
z Suitable for pipe diameters max. 100 mm
z Can be affected by currents of air etc.
QAE2... immersion sensors
Advantages:
z Measure "mean" fluid temperature
z No external influence on measurement such as: currents of air,
nearby pipes etc.
Limits:
z Time constant with sheath: 20 sec.
z Hard to change installation position if it proves incorrect