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Using a manufactured heating manifold

I own a 4 unit building with a 7 year old Weil Mclain mid efficiency boiler (86.5%). Currently I have 4 zones with circulaters and two separate standard hot water tanks. I would like to replace with a 5 zone setup that also provides dhw. I could probably add a connection to existing system, but it was put together by someone who didn't believe in maintenance. No way to do any maintenance without draining the entire building. This is my chance to clean up the mess and plan for the future replacement of the boiler with a high efficiency.

To save time and cost (maybe??) I am leaning towards a manufactured manifold that includes the pumps, air separator, thermometers, pressure tank, etc. Any pros or cons I should be thinking of ? Any recommendations ( I was looking at the moduheat's product line)? I have spec-ed systems for others, but I have never done a full install on my own, so I would appreciate expert opinions.




  • CMadatMe
    CMadatMe Member Posts: 3,086
    edited September 2010
    Keep it Simple

    I take it you pay for the fuel? Here's your shot at doing some outdoor reset. Do a heat loss, measure radation in each zone and find a heating curve. Rule of thumb for savings is, for every 3 degrees I can run a system with less than 180 degree water I save 1 percent of fuel. I would also zone with zone valves and use an "Alpha" pump as my system pump. Don't need any fancy prefab stuff. If you want to prepare for a mod/con could install a hydro seperator or pipe pri/sec now, especially if you are going to do outdoor reset. Will help protect the boiler.

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  • NY_ART
    NY_ART Member Posts: 4
    edited September 2010
    Next steps

    Thanks for the suggestions. I already have an outdoor reset control in place. Since the boiler is non condensing, I am limited to low end boiler return water temp of about 160F.

    I also appreciate the advice to go with the zone valves, but having seen them fail pretty regularly, I much prefer the more expensive but quieter and more durable circulator model. My friends who have zone valves are replacing a zone valve every two years or so. I know of ciruculator system that are going on their 10th winter with no problems. And they are quieter. Zone valves vs Circulators, probably another thread... (see heating help article "Banging Zone Valves")


    Anyway, my big issue is that I am looking at a complete re-piping of my boiler room. I need to add shutoffs/drain/isolation valves for each zone, replace failed flow checks (existing non IFC circulators), add a dhw new zone and rewire the existing system to allow for dhw priority (no zone controller in place, just hardwired from individual thermostats to the boiler control box and zone circulator). I need to know if it makes sense to simplify with a prefab manifold or if I would come out ahead by tackling all of this as individual custom tasks. Thanks again for any comments.
  • CMadatMe
    CMadatMe Member Posts: 3,086
    Reset the System

    Reset the system not the boiler. Put a heat manager of some type on the boiler. Pipe the boiler so it has protection. Simply pri/sec or like a said a hydro separator. Webstone makes isolation flanges with checks in them if you want to stay the circ route but you would significantly cut the electrical usage with using an Alpha pump and zone valves.You may want to read some of the articles at the below link. Full of helpful information.


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  • NY_ART
    NY_ART Member Posts: 4
    New idea...

    Good articles. This is a new idea for me, but it looks like it might be worth investigating.


  • Brad White
    Brad White Member Posts: 2,393
    160F Boiler Return Temperature

    BTW, you could use a modest amount of reset on that boiler or, at the very least, control the return water temperature lower than 160F. Normally 135F is fine for CI with gas or oil. Oil-fired can sometimes be lower, say 130, but why push it.

    Point being, you can set that a bit lower and save some more fuel for modest cost in the scheme of things.

    Using ODR though, you want your boiler supply water temperature to be at least ten degrees above our system supply temperature, to keep that mixing device, whatever you use, in control. Just another thought.

    Chris has your back though. The variable speed circulators, Grundfos Alpha or Wilo Stratos and soon the Taco Bumblebee, give great savings when used with good zone valves.
    "If you do not know the answer, say, "I do not know the answer", and you will be correct!"

    -Ernie White, my Dad
  • NRT_Rob
    NRT_Rob Member Posts: 1,013
    we used to be zone by pump

    as well because of poor zone valves.

    with alphas, or regular pumps and pressure bypasses, and good zone valves, you can have good results.

    we've been doing zone valves nearly exclusively for about 5 years now and have never, not once, ever had to replace a zone valve, on several hundred systems.

    I don't think anythings wrong with prefab panels, but if you know enough to specify the correct panel, and verify it is sized properly, you probably know enough to specify a custom panel that either better meets your needs or can save you some $$.
    Rob Brown
    Designer for Rockport Mechanical
    in beautiful Rockport Maine.
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