You are probably better off placing a mains powered 24V DC supply at the far end for raw control power of solenoid valves etc and keep your data lines separated. 59. In your body of you "question" you say "...it says 230v 50hz 180w 1.27a Fuse T5 ah 24vdc 5a. If the thermostat says heat is required, it allows the 24vac to go back on the W wire. In some designs using external power adapters there’s the concept of the “idiot diode” - a diode connected across the power input such that it will be reverse-biased (and therefor not conduct current) when the power is the correct polarity. Many things are the same, but there are always exceptions where mill, factory, or mining equipment is concerned. However, you should be aware that because the sprinkler solenoid’s resistance is pretty low, the operating current under 12VDC will be relatively high, around 400 to 500 mA. The big question would be how much current has to flow over that distance. 1. safety: 24DC will not generate sparks. Inside the thermostat are three switches/relays. If cooling is needed, 24vac is sent back on the Y wire. A2A. Get it as soon as Mon, Mar 1. but if we go for a higher voltage, it may generate spark in case of a short circuit/loose contact. I got confused as to what sort of power the solenoid needed because the relay had AC and DC written on the case. So the difference I suppose would be: 1. so 24 VDC can even use in Zone 1, Ex'd areas & instruments. I don't know if I was right. I guessed and told him it was 24VDC. In a typical four-wire system the 24vac is supplied by the R wire. 24VDC @ 1A means 24 volts direct current delivered at 1 ampere. You can simply use a 24V voltage regulator. 24VDC is a standard. I can say that 24VAC means 24 volts alternating current. In contrast, 24VAC power circuits are more complex and you can’t use the same circuit to directly interface with DC devices. All you need to do is to incorporate it into a normal power supply circuit. Thanks Max and Expert I knew the supply to the relay was 24VAC but the output was the problem. Alternating current VS. $12.59 $ 12. Re: 24 vdc relay on 24 vac Yes, your relay wont function correctly, as it will continually open and close with the cycliing of the AC current. Get a 24vac relay or build a rectifier for the DC relay if you must use the one you have. 4.8 out of 5 stars 33. 24 vdc relay on 24 vac any problems. No! Amazon's Choice for 24vac to 24vdc converter. The title "What is the difference between 24 VDC and 24 VAC" says one thing but then the body says something else. If the fan should be running, 24vac is sent back on the G wire. there are some basic reasons for using 24VDC in industries. If you aren't clear, you can not substitute something that delivers 24VAC with something that requires 24VDC, or vice-versa. The circuit diagram - Buck Converter, Yeeco AC/DC to DC Step Down Converter AC 2.5-27V DC 3-40V 24V 36V to DC 1.5-27V 12V Voltage Regulator Board 3A Adjustable Volt Transformer Power Supply Module. Along that same line of thinking, I wonder what would happen if you were to apply 24VAC to where the battery is supposed to be.