Wolf COB - Installation; General Notes

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8. Installation - general notes
Note:
Provide a ll and drain valve at the lowest point in the
system.
Safetyequipment
The COB has not been tted with an expansion vessel at
the factory. This must be tted externally (available from the
Wolf accessories range). The expansion vessel must be in
accordance with DIN 4807.
Thereshouldnotbeashut-offvalvebetweenthe
expansionvesselandtheoilcondensingboiler,
because otherwise the pressure build-up would
permanentlydamagetheboilerduringheating.
Thereisariskofsystemcomponentsrupturing,
givingrisetoariskofscalding.
Exceptions are cap valves upstream of the expansion vessel.
The safety assembly from the Wolf accessories range includes
an integral 3 bar safety valve. Route the blow-off line into a
drain outlet.
The minimum system pressure is 1.0 bar.
The oil condensing boiler is permitted exclusively for sealed
systems of up to 3 bar. The maximum ow temperature is
factory-set to 80 °C and may be adjusted to 90 °C if required.
Generally, the maximum ow temperature is 80 °C for DHW
operation.
There is no need for a minimum throughput at flow
temperatures below 80 °C.
We recommend a heating water pH value of between
pH 6.5 and pH 8.5.
Wolf does not assume liability for any damage to the heat
exchanger caused by oxygen diffusion in the heating water. In
the event of oxygen penetrating the system, we recommend
a system separation through the interconnection of a heat
exchanger.
If the limit curve is exceeded, an appropriate portion of the
system water must be treated.
Example:
Total hardness of the domestic hot water: 19°dH
System volume: 1 m³
This means at least 0.3 m³ = 300 l must be desalinated.
Permissible methods:
- Desalination using mixed-bed cartridges. These are
multi-stage ion exchangers. We recommend, for
example, using the "Megall Alu" cartridges from
Taconova for the rst ll, and later as and when required.
- Topping up with distilled water.
Total hardness in °dH
System volume in m
3
Water treatment
necessary
Water treatment not
necessary
0.3 m
3
Inhibitors (substances to prevent corrosion
and limescale deposits) and antifreeze are
not permitted. There is a risk of damage to
the boiler resulting from poor heat transfer or
corrosion.
Heating water
The return line to the appliance should have a dirt trap.
Deposits in the heat exchanger may lead to boiling noise, a
drop in performance or faults in the appliance.
Domestic hot water may be used as ll water and top-up water.
The addition of chemicals or de-scaling using single- stage ion
exchangers is not permissible.
In the case of high-volume systems or those where large top-
up water volumes (e.g. due to water losses) are required, the
following values must be observed.