W
W
W
W
WARNIN
ARNIN
ARNIN
ARNIN
ARNING
G
G
G
G
LP & N
LP & N
LP & N
LP & N
LP & NG ARE EXTREMEL
G ARE EXTREMEL
G ARE EXTREMEL
G ARE EXTREMEL
G ARE EXTREMELY FL
Y FL
Y FL
Y FL
Y FLAMMABLE SO
AMMABLE SO
AMMABLE SO
AMMABLE SO
AMMABLE SO
TTTTTAKE EXTRA PRECA
AKE EXTRA PRECA
AKE EXTRA PRECA
AKE EXTRA PRECA
AKE EXTRA PRECAUTIONS WHEN
UTIONS WHEN
UTIONS WHEN
UTIONS WHEN
UTIONS WHEN
PERF
PERF
PERF
PERF
PERFORMIN
ORMIN
ORMIN
ORMIN
ORMIN G ANY W
G ANY W
G ANY W
G ANY W
G ANY WORK T
ORK T
ORK T
ORK T
ORK TO THE HEA
O THE HEA
O THE HEA
O THE HEA
O THE HEATER
TER
TER
TER
TER
CT-08
page 1 of 1
rev 10/06
Bosch Water Heating
340 Mad River Park, Waitsfield, VT 05673
©
BBT
NORTH AMERICA CORPORATION
Bosch Group
DESCALING
MODELS:
1000P, 1600P, 1600H
260PN, 425PN, 425HN
Instructions for removing scale from heat
exchanger.
1. Disconnect electrical supply from the water heater.
2. Shut off the water supply to the water heater using
(installer supplied) isolation valve.
3. Open hot water taps to drain and relieve pressure
from the plumbing system.
4. Drain water from the unit’s heat exchanger by
disconnecting inlet and outlet water connections.
5. Connect the line (A) from the outlet of the circulat-
ing pump (installer supplied) to the inlet water
fitting on the water heater.
6. Using another line (B), connect to the water outlet
fitting on the water heater. Route the other end of
this line into a descaling reservoir.
7. Using a 3
rd
line (C) from the descaling reservoir,
connect to the inlet side of circulating pump. Verify
there is a filter on the end of the line in the
descaling reservoir.
8. Make sure all connections are “hand tight.”
9. Fill tank with descaling solution so lines inside are
submersed. We recommend a straight white vinegar
solution. If using a commercial descalant, refer to
manufacturer’s instructions on dilution with water.
11. Operate the circulating pump.
12. Make sure there are no leaks and the solution is
flowing from the descaling reservoir through the
heat exchanger and returning to the reservoir.
13. Run solution through the heat exchanger until the
solution returning to the descaling reservoir comes
out clear. (Changing to a fresh solution may be
necessary during this process)
14. Disconnect all lines and drain all solution from heat
exchanger. Properly discard solution.
15. Position a container below the hot water outlet and
reconnect cold water supply. Open cold water
supply isolation valve and flush heat exchanger with
clean water.
16. Shut cold water isolation valve and reconnect hot
water supply to the water heater.
17. Reconnect electrical supply to unit, open water
isolation valves, and return the unit to service.
PUMP
A
C
B
RESERVOIR