beduanBrass Electric Solenoid Valve, 3/4" 24V Air Valve Normally Colsed for Water Air Gas Fuel Oil

Marche tres bien

Work excellent

This is verifiably a direct acting solenoid valve, meaning that all movement of the diaphragm is from the energized coil itself. It does NOT require a minimum operating pressure to fully open, which is a much more common design to find. However, that capability comes at a price: operation requires a very powerful coil. But powerful coils draw high CURRENTS and cannot sustain that full current for more than very short periods without OVERHEATING. If your application only requires that the valve be energized for 5 seconds every few minutes and NO MORE, you'll probably be fine using it as-is. Otherwise this MUST be driven using some form of active current/voltage control, i.e. PWM.The resistance of the coil for the 1/2" 12 VDC version measures 5.5 ohms, drawing just over two amps at 12 volts, dissipating 26 watts of heat, which is quite a lot in such a small space. The secret to success is understanding that full power is only needed for a brief time to initially open the valve but a MUCH smaller current will HOLD the valve open. In my case I've got an Arduino Mega driving an H-bridge motor controller that actually powers the coil. To open, full current is supplied for about 100 milliseconds after which it drops to a fraction of that by switching to PWM with around a 30% duty cycle to maintainin the open position. Using this scheme I've yet to have a failure to open or to stay open and the body of the valve never goes above ambient even after hours of being powered.The only other things to be aware of are that it makes a VERY loud click when activated and the threads are NOT NPT, they are not tapered - so expect to use a LOT of sealing tape if using conventional pipe fittings.

I bought this to turn on water for my outdoor sprinkler system. My goal was to attach it directly to the master port 24V outlet on my sprinkler controller so that I would turn on water only when watering. To make a long story short, it didnt work because the sprinkler controller could only handle 750 mA and this valve, by itself, requires 850 mA (950 mA during initial activation). I could of course use a relay, and I was prepared to do that, but then I discovered this thing also heats up way beyond a level I consider safe. It is operating at 20W and the water does not cool it enough when the drip lines are running. So I gave up and ordered a different valve (https://www.amazon.com/gp/product/B06XX6XYD8/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1) which uses a motor instead of a solenoid and pulls a fraction of the current and stays cool.This valve does work, however. If you can handle the heat and the current, it will work for you. But to put this in perspective, this valve pulls far too much current when compared to other solenoid valves. Most 24 V AC/DC solenoids pull about 600 mA during turn on and then quickly drop to 300 mA when the valve is open. That was what I was expecting.

I keep getting sucked into this quagmire, While these valves are advertised as 1/2 in. NPT ports in the details, (all sizes say NPT in details), these valves all are British BSPT straight threads and NPT nipples or male pipe will bottom out and not seal correctly. I had seen the feedback about the problem with less detail. I shot craps knowing that I was using very low pressure and could use an adapter if necessary. You can buy these. I have before when this happened. Your first hint of trouble is that the AC voltage is listed as 110 Vac - - and this is the Chinese AC line voltage when not 220V. I live in China part of the year. China uses mostly BSPT threads in their plumbing. This seller is trying to hawk Chinese valves in the USA and he knows better. By the way, if used with "ON" duty cycle that is high, these valves will run hot and not be reliable when run on USA 120 Vac line or even higher is worse. Most USA line voltage is now approaching 130 Vac,, Look out for that too. Safety, possible flood and fire issue.