Checking The Diaphragm Expansion Vessel And System Pressure; Check Functioning Of Safety Valves - Viessmann VITODENS 222-F Service Instructions Manual

Vitodens 222-F B2TA 19 and 35 Service

Checking the Diaphragm Expansion Vessel and System Pressure

Check Functioning of Safety Valves

Perform check with the system cold.
1. If the nitrogen pressure of the precharged expansion
tank is less than the static pressure of the system,
top up with nitrogen via connection A, until the
inlet pressure is 1.4 to 2.9 psi higher than the static
pressure of the system.
The static pressure required at the tank is based
upon the static height of the system. The system
fill pressure value must be equal to the expansion
tank pressure value at approximately 60º F (15.6º C).
Note: Static head of 33 ft. (10 m) (distance between
boiler and topmost heat emitter surface)
corresponds to a static pressure of 15 psig.
2. Drain boiler/system and reduce pressure until the
manometer reading is "0".
3. Top up with water until filling pressure is higher than
the inlet pressure of the diaphragm expansion tank.
Note: With the system cold, the filling pressure
must be 1.4 to 2.9 psi higher than the static
pressure.Maximum operating pressure: 45 psig
Minimum operating pressure: 14 psig
4. When starting up the system for the first time,
mark this value as the minimum filling pressure on
the manometer.
Note: A lower manometer reading usually indicates
loss of water due to leakage. All leaks must
be repaired.
Ensure proper operation of low water cut-off(s)
(if applicable), pressure relief valve, and pump(s).
Check pressure gage, air vent and pressure relief valve.
Ensure that pressure relief valve does not leak and that
it operates in accordance with information provided by
the manufacturer.
Refer to maintenance instructions supplied
with low water cut-offs, pumps, etc.
Flush float water type low water cut-offs (if used).
Follow local regulations with respect to backflow
preventers.
If oil-lubricated system pumps are used, ensure proper
lubrication.
If motorized zone valves are used, refer to maintenance
instructions provided with zone valves.
Service
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