• Systematic measurement error: flow time too large with short flow times
• Systematic measurement error: flow time too small with short flow times
• Systematic measurement error: flow time too small (with Ostwald, CANNON-FENSKE or BS/IPRF U-Tube Reverse Flow Viscometer)
• Systematic measurement error: flow time too large (Ostwald, CANNON-FENSKE or BS/IP/RF-U-Tube Reverse Flow Viscometer)
• Systematic measurement error: flow time too small with short flow times (UBBELOHDE Viscometer)
• Systematic measurement error: flow time too small
• Systematic measurement error: flow time too large
• Drift of the flow times
• Increased stochastic scattering of the measurement values
• Excessive stochastic scattering occurring during automatic measurements using optoelectric barriers (possibility of total malfunction)
• Excessive stochastic scattering occurring during automatic measurements using TC Viscometers (possibility of total malfunction)
• Increased stochastic scattering in the case of short flow times (UBBELOHDE Viscometers)
• Periodically fluctuating flow times
• Malfunction caused by air bubbles during the sucking-in process of the liquid into the delivery vessel

Error causes:
after-flow error, Hagenbach correction too small

Possible error elimination:
experimental determination of the Hagenbach correction using substances having a similar viscosity and a surface tension as the measurement product

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Error causes:
after-flow error, Hagenbach correction too large

Possible error elimination:
experimental determination of the Hagenbach correction using substances having a similar viscosity and a surface tension as the measurement product; better: Viscometer with a smaller capillary diameter

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Error causes:
substance quantity filled in was too small

Possible error elimination:
empty, clean and refill viscometer

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Error causes:
substance quantity filled in was too small

Possible error elimination:
empty, clean and refill viscometer

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Error causes:
disturbance of the suspended level

Possible error elimination:
select viscometer with a smaller capillary diameter

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Error causes:
temperature of the bath liquid too high

Possible error elimination:
check temperature; if necessary, readjust thermostat

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Error causes:
contamination in the capillaries

Possible error elimination:
empty and clean viscometer, repeat measurement

Error causes:
temperature of the bath liquid too low

Possible error elimination:
check temperature, if necessary, readjust thermostat

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Error causes:
drift of the bath temperature

Possible error elimination:
protect the thermostat from direct radiation exposure, if necessary, replace thermostat

Error causes:
temperature-adjustment of the measurement substance not completed

Possible error elimination:
continue temperature adjustment until the time values are stable

Error causes:
evaporation of a highly volatile component; reaction of the product being analysed with the air

Possible error elimination:
apply pressing operating mode

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Error causes:
contamination in the viscometer

Possible error elimination:
empty and clean viscometer; repeat measurement

Error causes:
contamination in the product being analysed

Possible error elimination:
empty and clean viscometer; repeat the meas-urement with a filtered sample; if necessary, use a filter with a smaller pore width

Error causes:
air bubbles in the viscometer

Possible error elimination:
in the case calf pure matters with chemical and physical heat resistance, drive out bubbles by a shorter time increase of temperature clean and empty viscometer; during refilling, ensure absence of bubbles

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Error causes:
contamination of the optical sensors

Possible error elimination:
remove the viscometer tripod from the thermostat bath; clean optical system using non-denatured alcohol on a soft cloth

Error causes:
errors triggered by the optoelectric barriers as a result of the formation of bubbles, foam, or liquid lamellae

Possible error elimination:
use a TC-UBBELOHDE, OSTWALD, or CANNON-FENSKE Routine Viscometer

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Error causes:
Incrustation of the sensors (in the case of thermally instable media)

Possible error elimination:
transparent media: use optical flow-time measurement opaque media: use Reverse Flow Viscometer

Error causes:
wear and tear of the sensors

Possible error elimination:
replace viscometer

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Error causes:
beginning deformation of the suspended level

Possible error elimination:
select a viscometer with a smaller capillary diameter

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Error causes:
heating-up or cooling-down phases of the thermostats too long

Possible error elimination:
set the heating and cooling of the thermostat in such a manner that at least two complete temperature cycles are completed during one viscosity measurement cycle

Error causes:
no timely stability of the bath-liquid temperature (defective thermostat)

Possible error elimination:
replace the thermostat

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Error causes:
substance quantity filled in was too small

Possible error elimination:
UBBELOHDE Viscometer: fill up the measurement substance; others: empty and clean viscometer; repeat measurement

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