Need to put a dip in the S and R lines. Need air trap/vent?

tractorfarmer

Old house with oil furnace and water radiators. All the pipe work was done very well with every pipe slightly angled up towards the radiators to allow air to be released through each radiator. There is also a air trap/vent/expansion tank by the boiler. We had a steel beam installed and need to put a 1 foot dip in the supply and return lines going to 2 readiators. Is an air trap and air vent needed since those high spots can trap air? A big problem is the pipes are only a few inches from the floor boards, so there isn't much space. The guy doing the work seems to know how to do pipe work, but kind of shrugged when I asked about putting in a vent. He said something like, "I can put one in if you want." From what I have been reading, an air bubble in the system will make those radiators not function. Will the circulator just force the air through, or will the radiators on that branch not work if air is trapped there?

I am in a bind since the plumber is working with the contractor of the renovation, so the plumber is really working for him and I am not the customer (even though I am paying both of them).

Thanks in advance for any help!

Bondo

Ayuh,... So long as there's bleeders in higher points beyond, 'n an air scoop at the boiler, I'd think the air will purge out normally...

tractorfarmer

There's a scoop and vent at the boiler and each radiator has air bleeders, but doesn't the highpoint in the line leave room for air to get trapped? Would there be enough flow to push any air through a dip in the line?

bobinphx

common sense tells me that if you think air could get trapped there, it would. maybe think outside the box on this one??? Not really sure without a picture or two. There maybe another solution that will not trap air. The idea, as you have presented it is that the original plumbing design was to be sure that there was always an incline towards the air bleed valves. I would suggest trying however you can to maintain this design.

tractorfarmer

I don't have many other options. And cutting two 2 inch holes in the steel beam will upset the engineer. I know pics might help. Maybe I'll add some.

Bondo

Ayuh,... It shouldn't....

There's literally NO loss of strength from it...

REP

I might lower the boiler side piping so that it has a rise to the other side of the beam instead of a dip .You could use Pex to bridge the beam.That way you would not have any angles to trap the air.
If air is a problem I would definetely change the air scoop to a Spirotherm and you will never have a problem again.you will never have to bleed your system again.

tractorfarmer

Thanks for the input and ideas guys. Cutting the steel beam is one of the last things I want to try. And lowering the piping in the entire system won't be happening soon. If I did that, they would be more head banging then they are now. I am trying to keep the pipes up as far as they can be.

Regardless of what type of air trap I put on close to the boiler, there still needs to be a way to get the air out of the dip in the system. Right? Even filling it up initially won't let the water get by the air bubble. Am I thinking too much?

beenthere

Bleeder ells can be installed on the boiler side of the piping to those rads where the dip will be. Then coin vents or standard radiator vents can be installed to get the air out of the dip.

tractorfarmer

beenthere - So I only need to worry about venting the supply line where the dip is?

beenthere

Supply and return line. Circulators can't move air.

tractorfarmer

That's what I thought.