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High pressure piping for mod/con?

[Deleted User]
[Deleted User] Posts: 0
in THE MAIN WALL
of extremely stinky male bovine feces...

In a mono flow system, the fill pressure required is the same as it is for ANY closed loop hydronic heaitng system. 1/2 PSI per vertical foot of system elevation above the boiler, plus 5 PSI, typically a minimum of 12 PSI at the boiler.

Now, one thing I have learned over the years, is that the circulator required to move the water through the resistance values of all of the monoflow tees is a lot higher than one would think, and it WILL require a bigger circulator than normally used in other applications, but the operating pressure, it's the same.

As for pump sizing, it needs to be calculated. And it can be. You get the data, I'll crunch the numbers. I need the linear feet of main, the linear feet of each circuit of baseboard, whether it is up feed or down feed, and how many branch tees you're looking at. We'll assume for now that someone did a proper heat loss to size the BBR in the first place.

Your soldered joints will be fine... Your plumber, now thats a WHOLE nother problem...

ME

Comments

  • tonypete
    tonypete Member Posts: 24
    High pressure piping for mod/con?

    My pro performed my annual service yesterday on my 45 yr old American Standard boiler. All is well with my HW baseboard system and it has been running great. As the boiler is getting a bit long in the tooth, I asked him about the possibility of putting in a mod/con of some sort in the next few years. We discussed payback for the increased upfront costs, etc.

    Everything he said matched up with what I learned from lurking here for a few years except for one thing. He said that my current baseboard system would need to be repiped (not just the near boiler piping) due to the the higher water pressures in a mod/con system vs a standard atmospheric boiler. Huh?

    Currently, I have a one-pipe system with 1 1/4 in. black pipe 'main' with my baseboards fed with 3/4 in copper with monoflo tees. He said the soft solder joints in the copper would blow out and leak.

    Is this male bovine waste material?
  • tonypete
    tonypete Member Posts: 24
    I thought so. . .

    Thanks Mark - Specs you asked for:

    1) 180 linear ft of 1 1/4 black pipe (iron) main;
    2) Twelve BB mono flo branch circuits coming off of the main - all with 3/4 copper. Linear feet for each circuit 20, 10, 21, 10, 7, 18, 21, 8, 9, 6, 12, 21 = total 163 ft. I come up with 88 linear ft of finned BB radiators.;
    3) All branch circuits up fed

    Other - I used the Slant Fin heat loss calculator to ballpark my place at 40,000 BTU loss/hr. Seems about right - medium sized, brick ranch, new windows, decent insulation.
    Currently has a B&G Series 100 circ.
  • [Deleted User]
    [Deleted User] Posts: 0
    The results....

    TonyPete,

    I modeled your hydronic heating circuit using Siggys Super Hydronic Simulation Software. I doubled the number of elbows a square house with a one pipe system would have, and assumed half of the side branches would or could be closed off. I generated three different models, 1 with your current series 100 pump, one with a close match for Grundfos and one with a close matching Taco. You can now choose a common off shelf pump for replacement, and retire your oil can:-)

    Good luck, and send your plumber here to lurk if he wants to learn something new. If he hangs around long enough, he just might learn something.

    Be sure and tip (Buy a Brick) the bartender (Dan Holohan) on your way out the door. It's costing him good money to keep this bar room open.

    Let us know if there is anything else we can help you with.

    ME
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