Sample Analysis - Viessmann Vitomax HS M73 Operating And Service Instructions

Saline boiler feedwater requirements
Sampling of water and steam
Guidelines
Implementation according to ISO 5667-1
■
■ Preparation of sampling and handling of samples
according to ISO 5667-3
Sample cooler
The sample cooler is to be used for sampling.
Operating instructions for sample cooler
To be able to obtain a useful sample, the sampling line
must be flushed for an appropriate time.
Opaque or contaminated sample water must be filtered
prior to testing.
The water sample is cooled by the sample cooler to
approx. 25 °C.

Sample analysis

The sample must be analysed immediately after
extraction, as the values may change if left to stand
too long.
General
The samples must be analysed to ensure that the
boiler water properties match the values specified in
Tab. 15 and 16.
If the boiler water properties are analysed according to
other standards or by using indirect methods, these
methods must be calibrated.
Procedure
A clean surface with water supply and drainage facility
must be chosen to carry out the analysis. The required
equipment must also be kept in a cupboard at the
workplace.
Test equipment and standardised analysis procedures
Test equipment
The test equipment is sufficient for taking measure-
ments during ongoing boiler operation.
Standardised analysis procedures
If there are greater discrepancies, the values must be
confirmed via the corresponding standardised analysis
procedures. The cause of the discrepancy must be
remedied.
(cont.)
Sampling points
Sampling points must be located at representative
positions in the system.
Typical sampling points for boiler water:
Boiler feedwater entry valve
■
A drop chute or a continuous TDS line
■
■ Downstream of the top-up water treatment system or
the storage tanks
■ At the outlet of the condensate tank (if installed)
Note
Take the sample as close to the feedwater tank as
possible.
Note
For some types of water, the amount of solute matter
can be estimated by means of the conductivity. In addi-
tion there is a correlation between the pH value and
both conductivities.
Recommendation
Please contact Viessmann for a quotation for water
analysis components to aid continual monitoring of
the O and pH values as well as water hardness lev-
2
els.
Ion exchanger
1. The sample must pass through a strongly acidic ion
exchanger with a volume of 1.5 l.
2. Continuously measure the conductivity of the acid
(hydrogen ion concentration).
3. Continuously measure the conductivity in hydrogen
form.
The exchanger is installed in a cylinder, with a diame-
ter to height ratio of 1 to 3 or below. The exchanger
medium takes up at least
The ion exchanger must be replaced as soon as it is
depleted.
Water quality
of the cylinder volume.
¾
⅔
23