Filling And Draining; Filling - A.O. Smith ST-400 Installation, User And Service Manual

3
Legend
1. pressure relief valve
(mandatory if mains water
pressure is too high)
3. T&P-valve
4. stop valve (recommended)
5. non-return valve
(mandatory)
6. circulation pump (optional)
9. drain valve
11. service stop valve
12. temperature gauge
(optional)
14. draw-off points
15. expansion valve
(mandatory)
16. expansion vessel
(mandatory)
A. cold water supply
B. hot water supply
C. circulation pipe

3.1 Filling

0312731_ST_400-1000_NLENFR_V3.0, 2018-01-04

Filling and draining

Note
These products can be installed as vented and unvented. This manual only
discusses unvented installations. For information about vented installations please
contact A.O. Smith.
Installation Diagram
To fill the water heater, proceed as follows:
1. Open the stop valve (11) in the hot water pipe and, if present, the stop valves (4)
for the circulation pump (6).
2. Close the drain valve (9).
3. Open the nearest hot water draw-off point (14).
4. Open the stop valve (4) on the cold water side (A) so that cold water flows into
the water heater.
5. Completely fill the water heater. When a full water jet flows from the nearest
draw-off point, the water heater is full.
6. Bleed the entire installation of air, for example by opening all draw-off points.
7. The water heater is now under water supply pressure. There should now be no
water coming out of the inlet combination expansion valve or (if used) out of the
T&P valve (3). If there is, the cause might be:
- The water supply pressure is greater than the specified value (1.6 "General
specifications"). Rectify this by fitting a pressure reducing valve (1).
- The expansion valve in the protected cold supply set-up is defective or
incorrectly fitted.
IMD-0550 R1.0
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