Pond Boss Forums AERATION Systems questions Manifold heating up

I was wondering if it normal for the manifold off the pump to heat up? I just switched out a manifold that was so hot you could not touch it! (It was a manifold used for radiant heat)the heat would brake down the black poly airlines causing leaks. I made a new one out of 1/2 inch copper still gets warm though. the pump is a gast 3/4 rotary vane.

How much pressure is in the system? The more you compress the air, the hotter it gets.

I have to purchase a new pressure gauge. The one i have no longer works so I am unsure on pressure.

Over heating can be due to too much pressure in the system. If you get a new gauge get a 15 to 30 psi model so you can accurately read lower pressures.

That is actually untrue. The more you compress a gas, the colder it gets.

The compressor itself may get hot because it only knows one thing to do, and that is run.

You may have some issues with flow and plumbing.

JKB, I thought compressing a gas raised it's temp and decompressing a gas lowered it's temp? (something about the molecules being closer together and bouncing off one another more frequently?)

Yes, the other piece to the puzzle is the kenetic energy that is used to compress the gas.

For instance take a diesel engine. When the fuel is injected into the cylinder it doesn't ignite. But, compress that air 18 to 22 times, and the diesel fuel ignites - no spark needed like a gas engine. Again, kenetic energy needs to be added to the equasion to start in the form of a starter motor. IIRC, if a diesel isn't turning at least 220 rpm, then there isn't enough rapid compression to ignite the diesel fuel.

Esshup - I'll side with your assertion that compression increases the temperature of a gas (solids and liquids too). But, I would guess mechanical friction within the rotary vane pump is the source of the excess heat being conducted to the manifold.

Kelly, I'll buy that.

My bad! I guess the nitrogen compressors at the blueberry farm had me tricked. Pretty darn cold coming out of there. I guess I never really looked into it that closely.

JKB, wait 'till you start messing with liquid nitrogen. That's a wee bit chilly.........

One place that I was at was using a tanker of it in 2 days. By the time we got done with the project that usage was down to every 2 weeks. (process and equipment improvements)

FYI: Engineers at GAST mfg tell me that rotary vane compressors normally operate at 205F. Problems such as confined spaces, lack of air circulation, or restricted air flow create higher operating temps. Water boils at 212F.

Maybe an expansion chamber type of manifold would help.

Manifold may be hot to the touch but is not operating hot, Manifolds that are aluminum and or galvinized normally have heat dissapating hoses attached.Gast 1023 models 3/4 HP with a 2-5 outlet manifold would need hoses 18-24 inches prior to poly or any type of sub melt point of 225F.205F is a common open flow exhaust temp for wob-l's and vanes from friction components. Keep in mind these are "oil less" pumps.The exhaust outlet on a model 1023 is .375 and expanding to a .5 inch manifold would help more to maintain a higher cfm availability than reducing the outlet heat.Its always going to "feel" too hot.

Thanks guys, My pump is a Gast 1023 3/4 hp running a 1/2" copper manifold with 4 ball valves. I will try to find some heat rated hose to add as a buffer between manifold & poly tubing.

just visit your local "auto zone" type store and get insulated auto heater hose, 5/8 is EZ to find.Then reduce to whatever your poly is.PVC glue the reducer if it is poly as poly to poly does not clamp well. Good luck.

Pullo, how do you like your Gast pump? How many stations are you using and what style diffuser are you using? How long are your runs?

Thats exactly what I have on the end of my pump. 15 inch heater hose. Works great!

DL, I like the gast pump, plus I picked it up for $20 bucks! I am running 4 dual 9 inch membrane diffusers, each diffuser is about 250 to 300 feet from pump at about 12 foot deep, the pump works great. I added high temp hose between ball valves & poly & this solved my issue. I had swicthed to a premade manifold with ball valves used in radiant flooring, but it caused too much air friction! I went back to the old set up.