Viessmann VITOTRON 100 Installation And Service Instructions Manual page 9

Vitotron 100 Electric Boiler Installation/Service
Plumbing Installation Guidelines
(continued)
9. When possible, fill the electric boiler and hydronic
system with treated water. (i.e. soft or distilled
water) This will substantially extend the life of the
heating elements and reduce sediment buildup.
10. Freeze protection additives can be added. Only use
propylene glycol type freeze protection products for
hydronic heating systems that are non-toxic and
corrosion resistant.
The propylene glycol mix shall not exceed 50%, by
volume. 1 Under no circumstance should methanol
or ethylene glycol (automobile antifreeze) be added
to the electric boiler system as this may damage
internal components.
11. Insure purging of all air throughout electric boiler
system and related components.
12. This electric boiler requires a minimum
pressure of 7 psi in order to operate. Pressure levels
for hydronic systems typically are above the pre-
charged expansion tank pressure level (12 psi).
If additional pressure gauges are installed verify
reading as described on item 7.
13. The electric boiler is equipped with a pressure
differential bypass valve. This allows the minimum
flow rate to pass through the electric boiler when all
zone valves are closed. The valve will also help
reduce noise issues upon closing of zone valves or
actuators.
To adjust:
Turn differential bypass valve clockwise until it stops.
Turn on all heating zones and let them heat for a
couple of minutes.
Caution! piping can get hot quickly upon opening
the valve. Slowly open the bypass valve by turning
in a counter clock wise direction.
Stop turning once an increase in temperature is felt
on the outlet side of the valve. This is referred to the
tipping point. After reaching the tipping point continue
to turn the valve one complete turn. The valve is now
set to bypass excess flow as zone valves close.
Set the thermostats to normal set temperatures.
14. Proceed to the Electrical Installation.
Instructions for the Installer
9