Correcting pitch before insulating

malex

This discussion was started in another thread (<a href="http://www.heatinghelp.com/forum-thread/138976/Vents-woke-up-on-the-wrong-side">http://www.heatinghelp.com/forum-thread/138976/Vents-woke-up-on-the-wrong-side</a>) but I decided to start a new thread since this is really a different topic. It all started with loud vents on a cold morning and Ed and NBC among others helped me pin point the problem to large amounts of condensate causing the pressure and velocity to rise. Part of the solution was to not set back the tstat too much at night and insulate the pipes. Well, an assortment of 3' lenghts of 1" fiberglass and elbows an Ts arrived this morning.



Before I put on the crisp insulation I want to make sure the pitch in my mains is good as it will be hard to correct later without messing up the insulation job. I haven't had much issues with the pitch except occasional water hammer (one bang then quiet for a long time and not on a daily basis). But I am concerned because the way its pitched does not make sense to me.



Because the main makes a 45 over the centerhall beams it essentially is conterflow at first then the main is flat and resting on the beams and once it is passed the beams it turns into a parallel flow but the main is pitched the wrong way at first before it dips severely just before the wet return because of poor support. I have attached a diagram of the main, hope you can follow it.



My main questions are: is it OK that the main is flat in certain parts (or even pitched the wrong way) if no radiators are attached to those parts and condensate is limited to what is generated in those sections?



Should the main be resting directly on the beams?



How far apart should I put pipe hangers?



Should I try to 're-pitch' the pipes in some places?



Consider that the house is built in 39 and has settled somewhat and asbestos was removed and the pipe support put on may not have been adequate.

jpf321

section 4

as you well noted is probably a trouble spot. you say pitched toward the boiler but pitched toward the beam would be more telling .. how is water that settles in the 45 located at the right beam supposed to ever get out? can you drop it wet there somehow and drain the water from that section?

crash2009

Carjack and Hang em High!

Your question is well laid out.  I can see what you were talking about now.  The way you have it illistrated, it appears that the main has settled on the beams.  I think you could solve section 2 and 4, by simply, (yea right!) lifting section 3.  From the looks of pic 2,(in thread 1), you have the entire thickness of the floor joist, that the main could be lifted.  I think you would be surprised at how little you would have to move it, to change the pitch of 2 and 4.  After you get it up, it could be supported on both sides of the beam.  The 3 radiators runouts in section 2, would be my next concern.  Could they handle being raised a quarter or a half inch?  They might have been redone after the main settled and if so, the radiators might have to go up a quarter or half too, in order to maintain their slope.  Might be worth it to look into the radiators too.  As far as holding the main up, after you lift it, that depends on how much you want to put into it.  It could simply (there I go again!) be shimmed (not so good) between the beam and the main, or supported (very good) on both sides of the beam.  I have included a pic of a hanger system that I have used before, that will allow for future adjustments if nescesary.  You can get these hangers in larger sizes, and you can even get an insulated hanger at your local supply house.  Not the big box store, go to where the plumbers shop. 

malex

Pushing down pipe

So I have insulated near boiler (looks like a deformed storm trooper with all that white plastic), the short main that had good pitch and the beginning of the long main but have reached a stand still. It was easy enough to raise section 3 per my previous post by 1/4-1/2 inch and it does not appear to have affected the rads off section 2 as Crash feared. However, by raising section 3 I have only elevated the problem as the ends of sections 2 and 4 lifted up the same amount so the pitch remain pretty much unchanged (apparantly 2" black pipe is not very flexible).

To remedy, I am slowly "jacking down" the end with a jack between the joist and the pipe. Once I remove the jack I have a feeling the pipe will retain its old shape. Is there a better way (without re-piping) and is it advisable to try to 'bend' the pipe if gravity is not doing its job? 



Thanks

crash2009

Blocks

When you lift Section 3, the ends of 2 and 4 come up also.  I'm assuming you want the end of 2 and 4 to stay where they are.  Use some 2X4 or 4X4 blocking, at the ends of 2 and 4, between the pipe and the floor joist. 

malex

Eventually

Yes, I have been jacking down the sections and putting in blocks. When I insulate I will just have to work around the block or put some temporary insulation around it as gravity will eventually do its job and Im sure the ends will come down and the blocks will come loose. That is why I probably should install good hangers.

Hap_Hazzard

Hanger envy!

Damn, Crash! You find some of the coolest stuff! I want those hangers. I just finished replacing all the perforated straps that were supporting my mains with run-of-the-mill clevis hangers, and now I had to see these. Seriously thinking about starting over.