Recirculation Application; Operation Instructions; For Your Safety Read Before Operating; Your Water Heater - Bosch 520-HN -L Manual

Fig. 15 Plumbing connections and pressure relief valve
4.9

Recirculation application

Since recirculation through the heater is not allowed, the
following drawing is provided to outline a recirculation
application using the Protankless water heater with an Ariston
mini tank water heater. This schematic is for illustration only
and must not be used for actual installation without appropriate
engineering and technical advice from a professional properly
licensed in locality where the installation is made.
5
1
Fig. 16 Recirculation application
[1] Full port shutoff valve
[2] Circulator
[3] Check valve
[4] PRV
[5] Expansion tank
520 HN
4
2
3
6720608030-19.4Av
A small electric mini tank water heater (4-6 gallon size) must be
used for this application and designed so the pump will
circulate the water through the mini-tank and the building's hot
water return loop only. A timed or thermostatically controlled
operation of the pump is commonly done. The 520 HN must be
plumbed in line before the mini-tank water heater. Contact
Bosch Water Heating if further instruction is needed.
5

Operation instructions

5.1 For your safety read before operating your
water heater
WARNING:
▶ If you do not follow these instructions
exactly, a fire or explosion may result
causing property damage, personal
injury or loss of life.
A. This appliance is equipped with electronic ignition for
lighting the pilot and main burners. When turning the heater on,
follow these instructions exactly.
B. Before operating the unit, set the On/Off button to the On
position. The On/Off button is located on the front panel.
Smell all around the appliance area for gas. Be sure to smell
next to the floor because some gas is heavier than air and will
settle on the floor.
WHAT TO DO IF YOU SMELL GAS
▶ Close gas valve. Open windows.
▶ Do not try to light any appliance.
▶ Do not touch any electric switch; do not use any phone in
your building.
▶ Immediately call your gas supplier from a neighbors phone.
Follow the gas supplier's instructions.
▶ If you cannot reach your gas supplier, call the fire
department.
C. Use only your hand to push in the on/off control button.
Never use tools. Follow these instructions exactly. If control
button is jammed, close the gas supply and call a qualified
service technician. Attempted forceful repair may result in a
fire or explosion.
D. Do not use this appliance if any part has been under water.
Immediately call a qualified service technician to inspect the
appliance and to replace any part of the control system and any
gas control which has been under water.
5.2

Lighting instructions

▶ STOP! Read the previous safety information.
Operation instructions | 21
6 720 644 942 (2014/11)