Adding Radiator - Review Piping?

mroberts5

I will be adding a radiator, and would like a second set of eyes on my planned piping.

NOTE: This is all counter-flow - there are NO drips other than right before the boiler.

Below I show current setup and what I'm planning.

In summary:

• add tee to existing riser and runout through garage to relocated existing 42edr radiator.
  
• Add new 25 edr to top of existing riser.
  
• remove existing big mouth vent and add new venting to top of each riser (and maybe also end of runout)
  

EDIT: I do have the option of coming off the plugged line at the end of the 2.5" main. That is a 1.5" leg which used to serve a monster rad in the garage. But 30' of counter flow piping in the unheated garage makes me nervous.



Also - does anyone have any good reference material on proper swing joint design - Lost Art is quite light on this.

Thanks,
Matt

gfrbrookline

I would leave the big mouth where it is. You want to vent counter flow systems at the end of the mains. If you need to vent the riser you can tap it just below the top floor and install a Gorton D, but I don't think you will need it.

I am not an expert but I see red flag of 1.5 pipe draining into 1.25, I think this will cause a water hammer. I would think you need to reduce diameter as you go up.

acwagner

According to the tables, the pipe sizes you have are good.

How long is the run-out to the new 42 EDR rad location? You obviously want to figure out what kind of pitch you can get on that run.

Adding the tee to the riser may be a challenge. You'll probably end up redoing the whole riser.

What size is the plug at the end of line there? Is it big enough that you could add a new riser just for the new garage rad and not mess with the existing riser?

I've done swing joints using a normal 90 and a street 90. Keeps it compact. I don't like using two normal 90's and a close nipple--too hard to tell how much the close nipple has been threaded into one 90 vs the other. Seemed to be a source of leaks for me. I'm a homeowner, not a pro, so that's been my limited experience.

mroberts5

The run-out will be about 10 ft. I need to open the floor somewhere and confirm exactly what I'm working with. Will do today.

The plug looks it was for for a vent, but its so close to the riser with so little room above it it probably spit all over the place. So, no...too small.

acwagner

What's the plug at the end of the line in--a 90 or something? You could consider removing the whole fitting, extending the main some to get it out of the way of the other riser, and then building your new riser.

Just throwing some ideas out there.

With a tee off the riser, it will be hard to get any slope on the new run-out.

mroberts5

No room to expand, it's up against a foundation wall.

I was hoping to tee out to the side, then out in a 90 to get my pitch.

I'll redraw the riser detail later today after some more investigation on what's currently here.

I do have the option of coming off the plugged line at the end of the 2.5" main. That is a 1.5" lig which used to serve a monster rad in the garage. But 30' of counter flow piping in the unheated garage makes me nervous.

mroberts5

A little more info: The two first floor radiators (16edr & 25edr) in the rear come off the header at 90deg. The 35edr rad in the front and the plugged line come off at 45deg.

I already hear a bit of water in that line if my water level is high (wetter steam) - maybe going off the 2.5" main would be better and I just insulate the line very well.

If I do this, then the load on the one riser drops from 42 to 25.
And the new riser/runout comes off a tee on the main that used to service 60edr, will not only service 42.

Here is roughly how that would look

acwagner

I think both are viable. I would consider effective pipe length of the two options before going forward. I assume you're only depicting a portion of your overall system in your diagram. You might want to compare what your pipe length to the farthest rad currently is from boiler to rad, and compare that to the two options. You don't want the new rad over the garage to be so far compared to everything else it's a struggle to heat it during a normal call for heat.

With that in mind, I would consider upping the 1.25" riser on second option to 1.5". Not that it needs it for the EDR load, but smaller pipe has more friction.

mroberts5

good point on the effective pipe.

Half of the house I didn't show - there is 41' of 2" header (0.94 cuft of air) feeding 253 edr, piped parrallel flow. This has a big mouth vent.

There is also a 22.5 edr rad off the counter flow header I didn't show - thought I don't think that affects much.

If I run option 2, I'll have 1.07 cuft of main air before the farthest rad. Option 1 gives me 1.2

If I size the riser vents right I should be able to get there at the same time.

I'm torn between the two approaches. I think the first one (original post) will be much cleaner as all piping will stay in the walls, but I think the sizing of pitches required may make send second approach look better.

To confirm, - what pitch do I need on the runouts to that last radiator? Lost Art says 1in in 10 ft in general for counter flow, but in the section on upfeed risers, he talks about 0.5in per foot.

Thx

acwagner

The Lost Art seems to focus on the runout slopes between the main and the riser, but it doesn't specifically mention slopes from riser to radiator.

I assume the general 1" per 10' slope for riser to radiator section. Perhaps @DanHolohan can elaborate?

mroberts5

I could just slope the full height of a 2x8 joist and hope for the best

DanHolohan

@acwagner It would be the same as the runout slope between the main and the riser. 1" per 10'.

mroberts5

Dan, thanks for chiming in. To be clear: is there any downside to putting in MORE pitch?

DanHolohan

The more pitch there is the better.