Airlocked Radiant Heat Entran

HeatingHelp

This discussion was created from comments split from: Twintran tubing part of Entran II?.

Ellenmd

Radiant Heat Entran installed 1988 working smoothly until installed new boiler . 2nd year out the system seems airlocked can’t bleed to get it flowing . Now my heating guy wants to put clamps on each loop and bleed . Given the tenuous history i’m not loving the idea of clamping these 30 year old lines and expecting them to spring back. Is there a replacement hose of the same diameter out there now . I had one issue 10 years back w brittle line but it wa inches from the exhaust pipe and seemed it was the location error contributing to its demise. any suggestions on how to get airlock out ? 

hot_rod

If there are no leaks on the hose to manifold connections, no need to replace clamps. It used a special hose clamp that was smooth. If you use a typical hose clamp with the grooves in it that will cut through the jacket of the hose.

Often times those old small diameter tubes would sludge up. It behaves like an air bubble, but the hose is plugged.

If you can isolate the manifolds, sometimes you can connect a garden hose and blast them clear with 40- 60 psi water pressure.

If there are any strainers on the system, those should be cleaned also.

We would need pics of the entire piping to see if or where purge valves were installed.

Ellenmd

Ellenmd

the rappe points to a manifold which is hot - just above it the other pipe is cold .  we do a bleed and the return will get piping hot then not last. Here’s what is suggested to fix “

 when i totally drained that thing and all the flushing back n forth... it must of lost its prime and now is air bound. ive tried every which way to get it to work........and as much as i want to go with the theory that it was never a problem before.......there is no other reason it is not moving water through majority of tubes under the floor...ive ran this by others for opinion and they cant believe there were no valve/pet cocks on each return, as that is how they do it on headers now... aside from putting little ball valves in each return line going back to the main header.....i am going to see if i can come up about 24 vice grips or clamps to pinch off each line and flush each one , one at a time......as long as the return hoses are pliable , this should work......if i have to buy a bunch of vice grips it may weigh out better to get the 5/16 valves......but ill keep you posted as to what i find...... it is a great boiler set up you have...but water dont push air, thats why only the overhead piping is a problem......” 

just want to say we are having same issue in the slab. cold returns 

WMno57

Vise Grips
This is why I DIY.

WMno57

Ellen, if the tubing was pliable something like this could be used



I doubt the tubing is pliable.

Have you tried our find a contractor tool
https://heatinghelp.com/find-a-contractor/
If that does not list someone in your area, if you share your general location, we may be able to recommend someone.

@Erin Holohan Haskell , Ellen might need her own thread for this.

Erin Holohan Haskell

@Ellenmd, I've created a new discussion for you here.

Jamie Hall

You have to purge and blow out each individual line from the manifold. You simply can't do it with more than one line being worked on at a time -- the water, no matter how hard you pump, will go to the line with the easiest flow.

mattmia2

It was purged before somehow. It may be possible to get enough flow with a hose or a pump cart or the PRV that was on the old boiler to purge those well enough to get them to start flowing. Since that stuff may be somewhat fragile now more pressure also may damage something. A little soap can help the bubbles foam and be carried out too.

What sort of air elimination was on the old boiler and what is on the new boiler?

Am I reading right that they start out heating after it is purged but then some of them get air bound or are there parts you never got to heat?

hot_rod

Vice grip makes hose pinch off pliers, very handy for working on rubber tube systems. Pex also. A C clamp and two 1/2" wide strips of wood works also

You need to assure flow in each tube. That might involve removing each loop and blasting them clean with a garden hose and adapter to the Heatway.

Those are the correct clamps and should be reusable, blast them with WD-40

There was a handful of different Heatway barbed fittings made over the years, those were my least favorite. I think you needed to use rubber cement on them to get a good seal.
The problem is the ID or the tube varies a bit, and those copper barbs did not have enough taper to accommodate the tube ID tolerance.

Sludge in rubber is a not uncommon condition, even the most current version with all the O2 barriers in the braid. For some reason.

mattmia2

Ellenmd said:

the rappe points to a manifold which is hot - just above it the other pipe is cold .  we do a bleed and the return will get piping hot then not last.

Do the return tubes get hot or just the return main? If the tubes get hot that would suggest that they get purged enough to start flow but the air elimination at the boiler isn't good enough and as more air comes out of solution and is circulated out of the loops it gets circulated back in and airlocks the loops instead of being remove at the boiler.

hot_rod

When you bleed with the fill valve adding pressure, you have more pressure than the circ will deliver. What pressure are you purging with?
So fill water pressure drives hot water through the loop, but the small pressure differential the circ adds may not.
 Especially if flow resistance has gone up with partially plugged hose.