Closing off Central Airline?

[Beanie Seagus]

Hi All, Sorry to cross post this, but I wasn't sure which forum it best belonged in...

So i'm in the final stages of planning my central air system, i'm going to be ordering the LPH 45 Linear Piston Air Compressor from Jehmco, and creating my own manifold out of pvc and a whole mess of their AV!E air valves.

I have three big questions though that i need answered before i can pull the trigger.

The first is, is there any problem placing the pvc manifold on the ground rather than bolting it to the wall or ceiling? Is this going to cause the manifold to move around due to the air pressure, or worse yet, cause problems for the air attempting to go from the manifold up,5+ feet into my top shelf tanks? I want it on the floor so it remains out of site, my "fish room" is actually my girlfriend and I's living room, and all but two of my tanks are up against a single wall, so i'm not sure there is a need to place the manifold on the wall.

My second question is, another path of least resistance question... for the two tanks that are on the other side of the room, I was thinking i might just use airline tubing to plug them into the manifold. These two tanks are 55 gallons though, that use two airstones each, so we are talking about the use of 8 outlets, each with airline tubing that will need to span about 26ft across the room (not to mention any length of tubing needed to actually reach the sponge filters in the bottom of the tanks). The question is, will this work out ok? I fear that the long distance, plus the number of long distance airlines, plus the fact that these two tanks are my largest and deepest, may cause insufficient air to travel into these sponge filters. What are your thoughts?

My last question is, even assuming the appropriate ammount of sponge filters, as well as extra airstones in each of my 17 tanks, I will still not be running my Linear Piston air compressor at anywhere near its capacity, so i need to know how to "close the pvc manifold air circuit." Do i do this simply by capping both sides of the pvc? Or do i need some kind of air bleeding device? I'm trying to find a cheap solution to this issue, as i'm already sparing no expense with the rest of this airline set up.

Thanks in advance for your help!

 

[jonclark96]

In my experience, a loop on your pvc will enhance air pressure versus a straight manifold. This keeps even pressure across the outlets, versus a manifold that will have higher pressure close to the pump and decreasing pressure the further you get away. I'm not sure if its feasible with your set up, but its what I ended up doing in my fish room and without the loop, I was having trouble getting pressure to some outlets.

I've never experimented with the loop being below the tanks, but one of the main reasons that folks keep the loop up is to prevent siphons if you were to lose pressure on your PVC. with the air lines running down, you have the possibility of draining your tanks through the air line. I know its possible, because I've done it on multiple occasions. You can put check valves on the air lines to prevent a leak, but those will impact the amount of air getting to the device.

I know I didn't really answer your questions, but thought I'd pass along some of my experiences.

 

[chriscoli]

You can put the manifold on the floor....just keep the pump above the tanks.

+1 on John's suggestion of a loop. Those LPH pumps from Jehmco are pretty strong....I've got the 45 even. How many tanks do you plan to run on it? They've got an automatic shutoff safety if there's too much back pressure on them so keep an extra valve available to be opened in case you need to bleed off some extra air.

 

[Frank Cowherd]

I used 3 inch PVC for my original manifold. With any size over an inch you really do not need a loop though it will not hurt. If you use 3/4 or 1/2 inch PVC you are probably better off with a loop.
Using reduction fittings I added to my manifold when I set up and again when I expanded my manifold. I used 2 inch PVC for that.
I like the larger PVC since it is a bit easier to add the metal valves to a large diameter pipe than a smaller diameter pipe, particularly when you are adding valves when the manifold is in place and in use.
Air line tubing is really too small to transfer sufficient air from one side of a room to another. You could use one inch PVC or get clear plastic 1 inch hose and the appropriate fittings to connect to manifolds at each end of the room.
The connection of the pump to the manifold is almost always flexible tubing of 1 inch or so. You should be able to find out what the pump comes with or what you need to connect it to your manifold before buying it. Talk to the people at JEHMCO. They can tell you.

Linear pumps do not need a bleed. They cannot be over pressured like the old style piston pumps. IF you add more valves, need more air they just pump more air until you reach their maximum output. Then you need a larger pump.

 

[chriscoli]

Linear pumps do need a bleed if you're not using a certain capacity of them. This is Specifically how Jehmco helped me set up my fish room. They recommended I add in a valve just for that until my room was built out and they gave me very specific instructions on how to determine how much to bleed.

 

[chriscoli]

Here's a pic of their recommended bleed setup.

 

[Beanie Seagus]

chriscoli did you buy the bleed valve set up from them? Or was it a DIY project? What are the parts involved called? Whats the red nob called?

 

[chriscoli]

Jehmco had all the parts. If you call them they'll help. Mine is larger than you'll need so you may want to use something different. Just keeping the option to have an extra valve open is probably fine. The valve is all plastic and the gray thing is an silencer so you don't hear the whoosh as loud.

They told me to leave it open a little, and locate it where I could see my tank with the air deepest in it. Then adjust it so that that tank (and all others presumably) were getting air. If I add tanks I adjust again if needed.

 

[Beanie Seagus]

As an update and new batch of questions. I went ahead and sprang for the Jemcho LPH 60 so I would have room to grow. Currently got 20 outlets on it, and will probably add a few more in the coming days.

My question is, should the rubber elbow, and other components of the tubing and mainfold be warm or hot? Cause mine are.

This would concern me more, but when I try to bleed off more air, to theoretically let the pump cool more, I can't even bleed off all that much before air stops flowing through the sponge filters i have in my two 55 gallons tanks... That tells me that the pump actually needs the bleed valve closer to closed to do its duty.

That said, i am a little concerned because this is day one, and if the rubber elbow stays warm/hot, won't it melt/warp over time?

Looking for advice from folks who've had the Jehmco LPHs for a while.

Thanks in advance!

 

[JLW]

I would suggest a couple of things. First off, do you have the line as a closed bar, or as a loop? A loop will get you much, much better circulation and pressure, and extend the life of your pump.

If you have 20 outlets operating, what happens if you open the ones on the 55s, close the ones on the other (smaller) tanks a bit, then open the bleed valve?

The parts around the pump definitely do get warm, though it shouldn't be super hot. I don't know what temperature is acceptable for them, or how to quantify it, just that it should be warm, not so hot you can't touch it for a minute or two. The rubber should survive the temperature without issue.