Specifications

6 720 644 063
Installation instructions
25
Supply water piping
• Do not use PVC, iron, or any piping which has been
treated with chromates, boiler seal or other chemi-
cals.
• Mount a check valve and a shut off valve (near the
inlet).
• In order for the client to use the water heater comfort-
ably, 29 to 70 psi of pressure is needed from the
water supply. Be sure to check the water pressure. If
the water pressure is low, the water heater cannot
perform to its full capability, and may become a
source of trouble for the client.
Drain piping
• Expansion water may drop from the pressure preven-
tion device and wet the floor. If necessary, provide
drain piping or use a drain hose to remove the water.
Hot water piping
• Do not use lead, PVC, iron or any piping which has
been treated with chromates, boiler seal or other
chemicals.
• The longer the piping, the greater the heat loss. Try
to make the piping as short as possible.
• Use mixing valves with low water resistance. Use
shower heads with low pressure loss.
• If necessary, use a pump or other means to ensure
that the supply water pressure to the inlet of the
heater does not fall below 29 psi when the maximum
amount of water is being demanded. Install a pres-
sure meter on the inlet to confirm proper water pres-
sure.
Damage to the water heater as a result of poor water
quality is not covered by the Limited Warranty. To
ensure full warranty coverage, treat or condition water
that exceeds the target levels provided in this table.
Source: EPA National Secondary Drinking WaterRegu-
lations (40 CFR Part 143.3)
3.10 Water Treatment
If this water heater will be installed in an application
where the supply water is hard, the water must be
treated with either a water softener, which removes the
hardness, or by using sequestering agents, that reduce
the amount of scale deposits. Refer to the below tables
for suggested treatment and maintenance measures to
be taken based on the water hardness level. Damage
to the water heater as a result of water in excess of 6
gpg (100 mg/L) of hardness is not covered by the
Bosch Thermotechnology Corp. Limited Warranty.
Residential Use Treatment Guidelines
Description Max. Levels
Total Hardness
1)
100 mg/L (6 gpg) or less
Aluminum 0.05 to 0.2 mg/L or less
Chloride 0.05 to 0.2 mg/L or less
Copper 1 mg/L or less
Iron 0.3 mg/L or less
Manganese 0.05 mg/L or less
pH 6.5 - 8.5
Total Dissolved Solids 500 mg/L or less
Table 4
Zinc 5 mg/L or less
Sulfate ion 250 mg/L or less
Residual chlorine 4 mg/L or less
1) Maximum limit suggested by Bosch.
i
When installing a water softener, consult
with the manufacturer for proper sizing
and installation guidelines; the below dia-
gram is for reference only.
Type of
Water
Hardness
Level
Treatment
Device
Flush
Frequency
1)
1) Install Bosch Isolation Valves to allow for flushing.
Soft 0-1 gpg
(0-17 mg/L)
None None
Slightly Hard 1-3 gpg
(17-51 mg/L)
None None
Moderately
Hard
3-6 gpg
(51-100 mg/L)
Water Softener Once a Year
Hard 6-10 gpg
(100-171 mg/L)
Water Softener Once a Year
Very hard 10-14 gpg
(171-239 mg/L)
Water Softener Softener
Required
Extremely Hard > 14 gpg
(> 239 mg/L)
Water Softener Softener
Required
Table 5
Description Max. Levels
Table 4