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Circulating Pump

Rob_22-2 Member Posts: 10
We are replacing a boiler for a 2600 sq. ft environment. This was a gravity based system build circa 1923. The old boiler specs showed a BTU min at 110k and a max at 400k. While sizing the boiler is still a little tricky, we're thinking 150k to 200k @ about 83% efficiency should do the job ( I am staying away from high efficiency boilers due to price and what I've heard about several brands).

Is it safe to install a circulating pump on an old gravity based system? I'm familiarizing myself with the GPM formulae that will be in play (starting out at 4 inch then reducing). Also is it true that the circulator will live on the *return* side?



  • CMadatMe
    CMadatMe Member Posts: 3,086
    May I ask

    How did you come up with the 150/200K? That's like 60 btus a foot plus.  Do you live on the North Pole with no insulation and single pane windows? 

    Price? Is this nat gas or lp? Fed Credit is 1,500.00 plus any local utility rebates puts you just about in the price range of a boiler that you plan on choosing that will be obsolete in 2012. Sounds like a bad investment to me.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Rob_22-2
    Rob_22-2 Member Posts: 10
    Circulating Pump added info


    Thanks for replying...... Well not exactly the North Pole.... North Carolina to be exact. The estimate on size came from several vendors who sized the job based on the antiquated system that was there. They probably built the house around it back then. Very modern for 1923! It is a Craftsman style house. Two level with 11 rooms and 2 full baths. The sun porch is unheated. There are 14 radiators ranging from about 20 to 35 sections. All 5 column. There is heat loss as the cold crawl space is uninsulated.This is a NatGas setup. Bear in mind the rooms are graciously laid out size wise.

    We purchased the home through foreclosure knowing the heating system did not work. We tried in vain to get a boiler man to get it working but the best we could do was have one tell us that they wouldn't guarantee the repair for a week and we would be throwing money out the window.

    This is our 2nd home, soon to become a primary residence this year. I have a great steam system in NJ and I love radiant heat. Everyone in NC (at least this town) has tried to encourage me to switch to forced hot air. I am resisting.

    Without complicating this do you believe that a standard efficiency boiler can do the job? OK, I'll push to 87% efficiency. I just distrust the high efficiency units with computer boards that many owners (including at least one HVAC tech) say are a problem child.

    Just as a footnote, my sweethearts cousin (versed in homebuilding) said 150k BTU should be all we need and has agreed to do the job with me.

    Your advice is truly welcome, but the first question still stands as to wheather it's OK to add a circulating pump on a gravity based system.

  • Rob_22-2
    Rob_22-2 Member Posts: 10
    OK, I'll Take A Step Back


    After looking at so many of your posts it's obvious that High Efficiency is your thing. Help me change my mind here. I do have serious doubts in respect to computer boards and their programming (Toyota anyone?). In that respect it may boil (no pun intended) down to the dampness in the "basement" (a sprawling crawl space with a very large pit for the boiler). Subject to this environment in the summer when the system is not running will the system be at the mercy of this dampness? Are these High Efficiency units air tight around the boards? I'm flexible but steer me over these bumps.

  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    electronics in high efficiency boilers

    I am not a heating professional, but I did do a lot of electronic engineering when I was gainfully employed. In my experience, if an electronics board lasts 3 to 6 months, it is likely to last 20 years provided it does not get a screw-driver dropped on it, or a bad transient coming in the power input. Electronics are more susceptible to this kind of thing that are plain switches and relays.

    So first thing I would suggest would be to have a qualified electrician (there are knuckleheads in that profession too) go over your electric power to be sure the grounding is properly done, and to install a whole-house transient voltage surge protector in your power panel. I have a Square D QO series power panel, so I had a QO2175SB unit put in there. Since we cannot discuss prices here, suffice it to say that the cost of a TVSS installed by a professional electrician was quite modest compared to the price of the boiler. Of course, if you have a different power panel, you will need a different TVSS.

    From the panel, I have a dedicated circuit breaker that powers only the boiler system. One of the ground wires from the power panel goes to a water pipe right where the supply to the boiler picks it up. The code around here requires an additional ground wire to two stakes located elsewhere.

    The TVSS will take the worst of the spikes off the incoming power, but you can still get 1000 volt spikes past it. Thus, you may wish an additional surge protector close to your boiler. If this is for your own use, you might consider putting a fairly large UPS in there to provide both surge protection and to coast over short-term power interruptions. I have not done this.

    Also make sure your insurance is paid up, since a direct or very close lightning strike can only be protected against by insurance.
  • CMadatMe
    CMadatMe Member Posts: 3,086

    How far are you away from Charlottesville VA?

    I would strongly encourage you to get someone in their to do a heat loss for starters. The fact that you have all that cast radiation is a benefit so I encourage you to take advantage of it. I'm going to estimate that your heat loss is somewhere in the 100,000 btu range but probably more like 85,000 for the climate you are in.

    Now lets talk boilers. You could do a 87% gas boiler. It still has an electronic brain, is priced less than a mod/con but no federal tax credit. The tax credit alone on the mod/con will bring the price below that 87% boiler. If that is the road you want to take I would recommend the Burnham ES2 boiler with the outdoor reset card. Ooops those controls again.

    Here's my take. Contractors that are unfamiliar with certain products/controls tend to bash to justify their none use of them. Have their been problems with certain mod/con products, yes there have. There is no denying that. So find one that has no problems there are plenty of them. You using the Toyota analogy. Ok. So are you not going to purchase any car or just that brand of product?

    A mod/con is a homerun for this application. I would recommend a Viessmann Vitodens 200 but there are others that will also do the job. The control on the Viessmann is a software program not a MCBA board. there isn't that much in the boiler to fail. Attached is some info for you. With all that cast iron you would condense all year long providing you get that heat loss done, somone calculates all that radiation and comes up with the right heating curve.

    The comfort from constant circulation through those cast radiators will give you a combination of radiant and convective heat. Your rooms will be evenly heated. One last thing. Viessmann makes a phone module for the control. When your in NJ and are headed home you can call the boiler up and when you arrive comfort.

    I am in NY but we have branches in NJ if you need anyhelp or information. Drop me an e-mail if you'd like.

    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Charlie from wmass
    Charlie from wmass Member Posts: 4,314
    Faulty logic against high efficiency boilers

    Even that 83% efficient boiler has a computer board. All can be damaged by dampness and flooding. Running an indirect water heater will keep the boiler warmish and semi dry during the summer months.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Rob_22-2
    Rob_22-2 Member Posts: 10
    Time to travel

    Thanks all for comments, suggestions and ideas. Tomorrow is a travel day to NC. Minimal opportunity today for good research, etc., as I'm at Job2. I need to point out here that the proposed date to begin installation will be toward the end of May, 2010, giving ample time to get this nailed down fairly close.

    First, RadiantWizard, we're about 175 miles from Charlotte, Va. I'm inclined to give the heat/loss calcs a shot and post my numbers up here for starters when I get back. I'm not an Einstein but give me a tolerance of 8 to 10% and I think the next level will be in sight. If permissable some pictures may accompany this thread. The computer I was using today didn't have Adobe PDF reader software so some literature on the Viessman and the Burnham will get read during the week (but then again this is a HoneyDew work/vacation, besides the workload I have in mind already).

    JD, points well taken about boards! You've also pointed out that my panel situation is the Archilles heel here. Do you know there is still knob and tube in this house? Absolutely necessary is a dedicated, grounded line prior to installation. I still have to run a couple of lines to meet local code in the bedrooms and upgrade the panel. But don't get me wrong we *love* this palace. It just needs the right TLC.

    Charlie, Yeah but......... I really don't like a single point of failure. So I'm inclined to keep this separated. I haven't read enough to argue the pros and cons of indirect heating systems.


    Be back in a week
  • EricAune
    EricAune Member Posts: 432
    A change in thinking is what is needed

    These forced air systems everyone is trying to sell you, how do you think they operate?  Everything will utilize a computer board for operation. 

    Chris is right on about the cast iron being the perfect emitter for a high efficient boiler system.  You most likely have more radiation than you need, this will allow you to run at lower system temperatures and even further increase your efficiency. 

    Another question you might want to ask is:  Do I want my second home to cost me an arm and a leg to heat?    
    "If you don't like change, your going to like irrelevance even less"
  • Rob_22-2
    Rob_22-2 Member Posts: 10
    edited March 2010
    Some measurements & pix

    Well I'm finally back from the honeydew 'vacation'. Got everything else done except for what I wanted to do. Nothing new there. I've rounded up a few pix of the existing piping with measurements. The question is how to figure resizing any of the piping based on the GPM of whichever boiler we go with. This part of the art is the most tedious but most important. I still have to finish the measurements to come up with a satisfactory heat loss analysis.Header = 4.5" diameterRiser   =  3.5" diameterReturn (Main)= 2.5" diameterReturn (Sides) = 2" diameterI hope you can help lead to some good critical thinking here.Rob
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