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TECHNICAL
Q – How does an Anti-Freeze Valve work ?
By Patrick Gordon of Calafrica ( technical @ calafrica . co . za )
Patrick Gordon continues with his series on valves , this month on the topic of Anti-Freeze Valves .
As we are approaching winter , we will again be faced with freezing conditions . The question often asked is what we can do to protect the plumbing system from freezing .
There is a nifty product called an Anti-Freeze Valve that will help protect the pipes and fittings from the effects of freezing conditions .
So how does it work ? The anti-freeze safety device prevents ice build-up in domestic water circuits , avoiding possible damage to water storages and pipes in hydraulic , solar and irrigation systems .
When the minimum ambient operating temperature is reached , it automatically opens so that a minimum quantity of water may flow toward the drain , enabling a small continuous inflow of water ; this prevents water from freezing inside the pipe .
When the ambient temperature increases or in the event of contact with warmer water , the opposite action occurs , causing the device to shut off and circuit normal operating conditions to be restored .
A thermostatic element ( 1 ) in contact with the ambient air controls a shut-off spindle fitted to a passage seat in contact with the water contained in the pipe ( 2 ). When the ambient temperature drops to the minimum intervention value , the thermostat contracts . This causes the shut-off spindle to move and open a tiny passage so that water can drain out , allowing a small amount of water to flow in continuously ; this prevents water from freezing inside the pipe .
All images supplied by Patrick Gordon
For optimal system operation without the risk of freezing , it is recommended that the part of the circuit in which the safety device is installed is not connected to a dead leg but to the water supply network and a suitable pressure level is maintained .
While the anti-freeze device is in operation , the drain outlet will drip because of the cyclical opening and closing phases taking place correctly . The amount of water drained out varies in accordance with the outdoor temperature , the temperature of the water in the pipe and the length of piping exposed to the air . As a general guide , in the worstcase conditions , the amount of water drained out is less than 500ml .
Before installing the device , make sure that the system has been flushed and cleaned to remove any traces of dirt that may have accumulated during installation . The device must only be installed in a vertical position , as shown in the diagram , to permit a free and unrestricted downward flow of the water as it drains out . The device must be installed at the points of the circuit at risk of freezing so that the water may flow freely and to prevent pipes , storages or components located upstream of the device from freezing .
Water from the supply network , which is usually warmer than the air temperature up to the intervention value , laps the thermostat and causes the opposite action : the channel closes again and normal circuit operating conditions are restored .
For any further information regarding this topic please feel free to contact Patrick Gordon at + 27 ( 0 ) 83 303 1437 . PA
www . plumbingafrica . co . za @ plumbingonline @ plumbingonline @ PlumbingAfricaOnline April 2023 Volume 29 I Number 2