One-pipe counterflow project

Ross_24

I'm heading back to a client's home in a couple days to start preparing for a boiler replacement and just an overall system improvement.



It's a one-pipe counterflow system on a fairly large home (I thought these systems were typically for smaller houses).



I'm plenty experienced with near boiler piping, cleaning, etc. But I know you guys on here are WAY more experienced than little ol' me.



I'm curious as to what you think are the biggest obstacles with a counterflow system on a larger home? Will this require a dreaded higher system pressure because of the friction against the condensate draining back?



What should I be prepared for?

Jamie Hall

Really isn't a problem...

The biggest difference for the counterflow system -- once you get out into the system -- is that the pipes have to be big enough and have enough slope.  If the system doesn't bang, that's probably OK just as it is.  If it does, the solutions are the usual suspects -- sags in the pipes, that sort of thing.



Near boiler piping is a little more critical, but if you are generous and pipe the boiler properly (a drop header goes a long way here!) that shouldn't be a problem, either.



And no, you don't need higher pressure.  1 1/2 pounds should be ample.



Venting venting venting -- I'll bet you a coffee that you'll find that you could use more main venting...

Ross_24

thanks

Yes I'll be putting in a nice drop header for sure. I've got a quick sketch of the near boiler piping I drew up today.



(2) 2" risers coming up off the boiler to a 3" drop header. The (2) mains will then take off from there. I've included a hartford loop as well. Any thoughts?

Eric_32

You will...

You will also want to roll those 3" tees feeding the building on a 45° angle and add 45's to get back straight. That will keep the incoming condensate from raining down on the steam in the header.

Charlie from wmass

No hartford loop required

Increase equalizer to 2 inch. Header needs to be one pipe size larger than recommend.

Ross_24

I agree

the Hartford loop is not required, but I've chosen to include it because that's what our inspector looks for when he sees steam. Also, if the homeowner decides to hop online and do some research they may read about Hartford loops. A few fittings help us to avoid a headache down the road. Unless you think the Hartford loop would affect performance?

Charlie from wmass

What size of boiler are we talking here?

Also what make of boiler of boiler are we talking? A single 3 inch riser has lower velocity than two 2" risers. If you need a 3" header with parallel flow you need a 4" with counter flow. If you use the funds going into the drips to buy a larger header and equalizer. Make sure you use a drop header set up though, even if you use a single riser.

jumper

Adequately dripped counterflow are unfairly maligned. Bunch of ski lodges in Laurentians (Quebec) had them and they worked well for generations.

gerry gill

You should pipe into the Top of the mains like was done in this picture, and drip the rear of the mains.

Eric_32

gerry gill said:

You should pipe into the Top of the mains like was done in this picture, and drip the rear of the mains.

Now that is some slick piping there ^^^ Where are you getting your threaded wyes from?

gerry gill

Lakeside Supply in Cleveland has them.