A.O. Smith TWI 35-130, Инструкция по установке, эксплуатации и обслуживанию

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14 Instruction manual TWI 35-130 G/TWI 45-190 G
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2.5 Safety of the installation Apart from the standard security of the device, the installation shall further be
protected using an expansion vessel, an expansion valve, a pressure reducing
valve, a non-return valve and a T&P valve.
The use of an expansion vessel, expansion valve and/or pressure reducing
valve is dependent on the type of installation: unvented or vented.
2.5.1 Unvented installation
With an unvented installation an expansion valve and an expansion vessel
avoid a too high pressure in the tank. This prevents damage to the tank.
A non-return valve avoids a too high pressure on the water piping. This valve
also avoids water from the tank flowing into the water piping. The pressure
reducing valve protects the installation against a too high water piping pressure
(> 8 bars). The parts are mounted into the cold water system (3.6.1 “Cold water
side”) .
2.5.2 Vented installation
With a vented installation the open water tank absorbs the overpressure. The
height of the water tank determines the maximum operating pressure in the
tank. The maximum operating pressure is 8 bars. The installation shall also be
equipped with an expansion valve of the hot water piping that flows out into the
water tank. In the ideal situation this should flow out in a separate discharge
channel, otherwise in the open water tank. The device shall also have a stop
valve on the water side (3.6.2 “Hot water side”) .
2.5.3 T&P valve
A T&P valve is only obligatory with unvented installations. However, A.O.
Smith recommends using a T&P valve with vented installations as well. A
T&P valve (Temperature & Pressure valve) monitors the pressure in the tank
and the water temperature at the upper part of the tank. The valve will open
when the pressure in the tank becomes too high (> 10 bars) or when the water
temperature gets too high (> 97°C). The hot water can now flow out of the
tank. As the device is under water piping pressure, cold water will automatically
flow into the tank. The valve remains open until the unsafe situation has been
removed. The device typically has a connecting point for a T&P valve (3.6.2
“Hot water side”) .
Operation of the device