Solenoid not opening fully

[DaveSeattle]

Hi all,

I am trying to replace a motorized ball valve with a solenoid on my HLT, but the solenoid doesn't open properly: it only lets a tiny dribble of water through. Does anyone know what could cause this?

I verified:

• That the marked arrow points in the direction of flow
• That the solenoid expects and is getting 12v DC
• That the water flows at the expected rate from the HLT without the solenoid in place
• That it's not just a defective part, by trying multiple different units (of the same type).

Here is the interesting bit: the solenoid does open fully if I give it a good long suck (insert jokes here), as if it weren't getting enough water pressure to open the diaphragm. And I have others of these units on city water pressure lines that open properly. But they're sold as gravity-fed and rated for 0-0.8Pa.

Any ideas what the issue could be here?

David

 

[RiverCityBrewer]

I know you said it is getting a 12VDC source, but is it getting enough amperage to open the valve? Also your .8Pa rating confuses me... if my math is correct that is about .00014 psi. Is it only rated to that much or does it take at least that much to open the valve? A spec sheet to the valve might help.

Cheers,

Joe

 

[DaveSeattle]

It's drawing from a 5A supply through a relay that only had the control board pulling power when I tested it, so there should be plenty of current to spare.

I was doing the rating from memory - it may be 0.8MPa or kPa. Main point is that it goes to 0 on the low end, so it should open without any pressure. I've tested it with only a tiny bit of water in the tank so I'm sure it's not an overpressure problem either.

 

[Brumateur]

What exactly solenoid type/spec and what are you are using to power it?

 

[DaveSeattle]

Here are the specs: Pressure 0-0.8 MPa, power 4.8w, voltage 12v. No brand or model, I got two from oscsys and one from eBay. It's powered from a 5a 12v power supply, fed through a relay controlled by the Brewtroller. The relay is working properly, the dribble shuts off and turns on when instructed by the BT.

One thing I hadn't tried is hooking it up backwards, so the flow is against the arrow. I may try that tomorrow.

 

[Bill_in_VA]

I think these types of valves are pilot operated and require like 15psi to open. I don't believe it'll work in gravity (or even chugger/march pump) system. This fact probably got lost in the chinglish translation... Try hooking to supply water to test it.

 

[DaveSeattle]

I went to grab the specs for you all, and in the process figured it out: the valve is marked 0-0.8MPa, but actually the full spec says 0.02-0.8MPa. 0.02 MPa is 2.9 psi is 80" water column. So this valve ain't gonna open unless the HLT is really full . Anyone know of a true low pressure open solenoid at a reasonable price?

 

[RiverCityBrewer]

Check out valves4projects on ebay... they should have a good selection of gravity feed valves. Be sure to check the temp ratings if you are planning to use it with your HLT. I've used them for various projects over the years, if you have questions be sure to contact them, they are very helpful.