Winterizing For Seasonal Use; Mineral Scale Build-Up - Bosch Greentherm T9800 SEO199 Installation And Operating Instructions Manual

▶ Remove appliance front cover, see page 11.
▶ Remove cover from the air filter.
▶ Loosen two philips head screws.
▶ Remove air filter from the fan.
Fig. 36 Replace air filter
NOTICE:
Appliance malfunction!
▶ Air filter should not be removed during appliance normal
operation as, overtime, will lead to burner blockage
requiring expensive repair.
7.2

Winterizing for seasonal use

The water heater must not be installed in a location where it
may be exposed to freezing temperatures unless connected to
electrical power. All water must be drained from the heater in
order to avoid damage to the unit from exposure to freezing
temperatures.
NOTICE:
Use of agents such as anti-freeze is not permitted and voids the
warranty, as they may cause damage to the water heater's
internal components.
1. Press ON/OFF switch on the water heater to turn OFF the
heater and unplug power supply cord. The display should
be blank.
2. Shut off gas supply to heater.
3. Shut off the water supply to the water heater using installer
supplied shutoff valve.
4. Open hot water taps to drain and relieve pressure from the
plumbing system. If water continues to flow after 5
minutes, a crossover of the hot and cold water pipes is
present and must be corrected before proceeding.
Greentherm T9800 SEO 160/199 | SECO 199 – 6 720 817 281 (2018/12)
5. Disconnect the inlet and outlet water pipes from the water
heater. Place a small bucket underneath the water heater to
catch residual water remaining inside the water heater.
6. Using an air compressor, blow short bursts of air (25 psi
max) through the inlet water connection until there is no
water present coming through the outlet water connection
of the heater.
7. Empty condensate trap.
8. Reconnect water fittings, refill the condensate trap and
return heater to service when danger of freezing has
passed.
7.3

Mineral scale build-up

Periodic descaling may be necessary in areas with high mineral
content in the water, (see table 8, Water Quality). Scale buildup
in the heat exchanger may result in lower flow rates, error codes
of AA, E3, E5 and boiling sounds in the heat exchanger.
A water softener is required if the water hardness exceeds 14
grains/gal (200 mg/l) calcium carbonate. Damage to the water
heater resulting from hard water/scale deposits will not be
covered under warranty.
Descaling using a pump
▶ Disconnect the electrical supply from the water heater.
▶ Shut off the water supply to the water heater using (installer
supplied) shutoff valve.
▶ Open hot water taps to drain and relieve pressure from the
plumbing system.
▶ Drain water from the unit's heat exchanger by
disconnecting inlet and outlet water connections from the
heater.
▶ Connect a line (A) from the outlet of the circulating pump
(installer supplied) to the inlet water fitting on the water
heater (see fig. 37).
▶ Using another line (B), connect the water outlet fitting on
the water heater. Route the other end of this line into a
descaling reservoir.
▶ Using a 3rd line (C) from the descaling reservoir, connect to
the inlet side of circulating pump. Install a filter on the end
of the line in the descaling reservoir.
▶ Make sure all connections are "water tight.".
▶ Fill bucket with descaling solution so both lines inside are
submersed. We recommend a straight white vinegar
solution. If using a commercial descalant, refer to
manufacturer's instructions for proper dilution ratio.
▶ Operate the circulating pump.
▶ Make sure there are no leaks and the solution is flowing
from the descaling reservoir through the heater and
returning to the reservoir.
Maintenance and service
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