Ideas?? Dema Injector Issue

[MEP001]

I usually try not to ask the obvious questions, but you did restrict the DEMA to make it draw? I don't know what model you used, but the ones with a variable flow have to be trimmed to your flow or you'll never create a suction.

 

[traveler17]

I usually try not to ask the obvious questions, but you did restrict the DEMA to make it draw? I don't know what model you used, but the ones with a variable flow have to be trimmed to your flow or you'll never create a suction.

yeah these do not need a trimmin’

 

[Randy]

That's really odd. I've been using DEMA 203C injectors on my self serve equipment for well over 30 years, they still work fine. I should probably change out the internal nozzle.

 

[traveler17]

That's really odd. I've been using DEMA 203C injectors on my self serve equipment for well over 30 years, they still work fine. I should probably change out the internal nozzle.

I do have another on the way along w the hydra flex, which I use for the pre soaks but yeah I’ve never had an issue. Only thing I can guess is they are faulty. Gotta be it, I mean I hope that’s it

 

[JGinther]

I doubt they are faulty... It's about the flow rate. The dema has a wide flow rate range and the nozzle bushings are what narrow it down so that it can create a venturi (unless you are using a b model which has a bypass screw to adjust as mep said). Since you were able to get suction from a 5.5 injector, chances are you didn't have enough flow for the dema. A smaller dema should have worked, or more flow should have worked. As Hoskins mentioned, usually that's caused by a faulty open solenoid on another product plumbed in parallel to the one giving you problems. On a Belanger, the flow is pump speed adjustable. But on other equipment, usually the air pressure setting causes too much backpressure to maintain accurate injector flow rates.

 

[Greg Pack]

Yeah, I'm old school and kinda still like hydrominders. Any change in product flow rates (clogged nozzles, too much air, etc)can throw the injectors off.

 

[traveler17]

I doubt they are faulty... It's about the flow rate. The dema has a wide flow rate range and the nozzle bushings are what narrow it down so that it can create a venturi (unless you are using a b model which has a bypass screw to adjust as mep said). Since you were able to get suction from a 5.5 injector, chances are you didn't have enough flow for the dema. A smaller dema should have worked, or more flow should have worked. As Hoskins mentioned, usually that's caused by a faulty open solenoid on another product plumbed in parallel to the one giving you problems. On a Belanger, the flow is pump speed adjustable. But on other equipment, usually the air pressure setting causes too much backpressure to maintain accurate injector flow rates.

Agree w everything you said which is why I’m stumped. Put the exact 204 C on and the same bushing. Replaced 1 valve parallel to it that was leaking. I agree I’m losing the flow to create the draw but I’m just not sure where.

 

[JGinther]

Belanger units usually have ball valves under the solenoids. Have you tried turning off every one except the one with the injector? Does it appear to be putting out a full spray of water in the bay?

 

[traveler17]

Belanger units usually have ball valves under the solenoids. Have you tried turning off every one except the one with the injector? Does it appear to be putting out a full spray of water in the bay?

Actually I didn’t and I don’t know why. I’ll do that today and yeah the arms are putting out the normal psi I had prior to the problem. Thank you for the advice!

 

[traveler17]

Belanger units usually have ball valves under the solenoids. Have you tried turning off every one except the one with the injector? Does it appear to be putting out a full spray of water in the bay?

Hey J , just an update I closed the 3 ball valves and left the wax option open and still have no draw and same pressure I’ve always had in the arm manifolds. Very odd. Appreciate the try

 

[JGinther]

At a high enough flow, the injector has to work (if its plumbed in right). By work, I mean create vacuum - it just a matter of the fluid dynamics and the shape of the part. So, either there isn't suction because there isn't enough flow (a myriad of possibilities), or the injector ball/spring is stuck.

 

[traveler17]

At a high enough flow, the injector has to work (if its plumbed in right). By work, I mean create vacuum - it just a matter of the fluid dynamics and the shape of the part. So, either there isn't suction because there isn't enough flow (a myriad of possibilities), or the injector ball/spring is stuck.

Gotcha. I appreciate the input!!