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Replacing Gas Boiler Questions

dcv2002dcv2002 Posts: 3Member
We are in the process of replacing a Weil Mclain CG-5 (140,000 BTU/hr) gas boiler. The cast-iron block has a small drip leak and my serviceman after contacting WM for me, believes that this will not be covered under WM's limited lifetime warranty repair since it only covers manufacturing defects and those are only usually found after 10 years and this is a lot older than 10 years. The amount of labor + cost of part would probably be better off to just replace the boiler.



Boiler is hooked up to a WM Indirect HW tank (Plus 60), it is the same age as the boiler.



We live in a 3000 sq. ft house with two-story foyer and family room. Long Island, NY. Have seen temps as low as -10 to -15F in January. 3 zone system. 1 for IHW and a zone to air handler in basement for 1st floor and to attic air handler for 2nd floor. We need to have a 20% glycol mixture in the system due to air handler in attic.



OK, our installer has recommended either replacing just the boiler (and everything around it) with a Peerless MI-05 for lets say $X (not sure if pricing is allowed here). This would hook up to the current WM IDW tank.



For $X + 4500, he suggests the NTI Trinity Ti200c which would do both the heat and HW, so get rid of both the WM boiler and tank. This would include new exhaust routing outside to the side of the house, outside temperature gauge, etc. Installer has said he has installed plenty of these in recent years with no problems.



My concerns are (Trinity):

1. New technology scares me a little, especially at the extra cost. Especially the electronics which are only covered for 16 months under warranty.

2. Having condensate drip from the boiler and have to be pumped outside also is a little worrisome as I have a finished basement.

3. I can't assume my serviceman is never going to retire, so I'm unsure if servicing will be readily available as with a typical cast-iron boiler.



There are some benefits that I can see such as replacing everything at probably an additional $2000 (Note: this takes into account that we probably will have to replace the WM IDW in a few years at a cost of $2000+) with a high-efficient boiler sounds like I could save money in the long run, but the payback seems to be far off. We plan to be in the house at least another 12 years. Also, I'm kind of a tech-geek so this stuff sounds cool.



However, I've seen through research that a boiler hooked up to a IDW is the most cost-effective way to heat water and house. Also, I am assuming that the Peerless boiler is standard fare and could be services by most heating contractors. One concern I have is about only changing the boiler and not the IDW, if I go the Peerless route. Should I do both at the same time?



Thanks in advance...

Comments

  • Chris_110Chris_110 Posts: 3,056Member
    edited March 2011
    Heat Loss

    Could you please provide the heat loss that was calculated to come up with the replacement boiler size. Please, if possible, break it down to each zone the air handlers are providing heat to.What size are the air handlers?



    Without this information, atleast for me, does not provide enough information to give you with a proper anwser. Condensing technology is not new to the industry. No matter which type of system you choose, whether cast iron or high efficiency, will only operate and be as reliable as the installation. As a consumer you should be more concerned with the installer then the piece of equipment.



    A typical home of your size in LI that is reasonably insulated with updated windows would only have a heat loss of 75,000 to 96,000. I would say the choices provided to you are for an oversized boiler. Oversized equipment leads to more maintenane, service and reduces the life span of the equipment. These among other reasons are why a heat loss of the home is necessary.  
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • dcv2002dcv2002 Posts: 3Member
    Heat Loss - First Run

    Ugh, I typed this whole post in and it asked me to log in and lost what I wrote...



    So I'll do it shorter this time:



    House is 2 story with concrete slab full basement.

    1. Basement: 156 ft perimeter, 1520 sq. ft. 90% finished. Just carpet on floor:

    Heat Loss: 22.37 MBH

    2. 1st floor: 156ft perimeter, 1520 sq. ft. (Does not include attached garage)

    Heat Loss: 23.17 MBH

    3. 2nd floor: 216ft perimeter, 2270 sq ft. (Master Bedroom over uninsulated garage)

    Heat Loss: 39.60 MBH



    Total Loss: 85.1 MBH. For a 80% efficient boiler = 106 MBH. Peerless MI-04 is only 105 MBH, MI-05 is 140 MBH. Current boiler is 140 MBH. I did not add anything for Indirect HW since it is on priority relay.



    Trinity Ti200c is 182 MBH @ 95%, so this would be oversized but it also produced hot water (4.8 GPM @ 120F). Current Indirect HW does 5.5-6.0 GPM. So sizing of this is probably to make sure enough HW to shower and run appliances.



    My concerns:



    1. If go with Peerless MI boiler, should we also changed the tank with it to match the ages? Would that be cost effective.

    2. Is the Trinity Ti200c overkill? Especially for Long Island? I can't access my gas bills right now, but we spend $2100/yr for gas delivery.

    3. I just want something that I don't have to worry about. Just have to get serviced regularly and will last the remainder of our time in the home (12-15 years).
  • Chris_110Chris_110 Posts: 3,056Member
    Take a Look

    At the Burnham ES2. I'd question the heat loss of the basement. If 4 ft of it is under ground no way it's loss can be at the 1st floors loss. Boiler should be sized for the heat loss. You don't deduct the efficiency of the boiler gross to match the heat loss. If you want to be conservative use the DOE rating if the boiler is in a conditioned space not the net..
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • RobbieDoRobbieDo Posts: 131Member
    Trinity NTI

    This is a modulating boiler. They also make a 150 in that model with domestic HW. It will produce approx. 5gpm with 45 degree incoming water temp. I haven't had any issues with the ones I've installed, I live in upstate NY where it gets pretty cold and is still cold.
    Rob
  • GordanGordan Posts: 891Member
    edited March 2011
    Are you unhappy with the indirect?

    If not, you don't need to replace it. The buffer capacity it provides will (most likely, you can calculate this) allow you to meet the peek DHW usage even with a boiler that's sized to your heat load.



    A combi boiler always costs more than the non-combi equivalent. If you've already invested in the indirect and it works fine, why toss it out? Whatever you replace it with will also have a finite lifetime; it would seem to make sense to get your money's worth out of it.
  • dcv2002dcv2002 Posts: 3Member
    Thanks

    Thank you for the responses.



    We are happy with the way the indirect HW heater works. We have a monthly gas budget of $173/month, which for the size of our house does not seem all that high. (We keep out house ~65-66F).



    However, the IHW is 15 years old and numerous people in our development (all the same systems) have replaced their tanks already due to leaks (leaky tank, leaky coil). With a finished basement, I'm wondering if waiting until the tank start to leak is a good idea?



    So do we ride the current indirect HW tank until it goes within 5 years, or just replace it now. Decisions, decisions.



    About the NTI Trinity, it looks cool and is seems to be very efficient. My concerns are:

    1. It's only been around for 7+ years, does anyone really know the true lifespan of it

    2. It needs to have a thorough service every 18 months. That means opening up the HX for cleaning, etc. Does this servicing add wear and tear to the boiler.

    3. My research has shown that a boiler + indirect HW is better than having a tankless boiler like the Ti200c. From memory, our gas bills were probably < $1 day from May-Sept.

    4. New exhaust piping sticking out the side of the house. Yes it is on the side of the house where no one will see, though.



    Right now we are most likely going to go ahead with the Peerless MI boiler. I will call the installer today, state that I don't think we've ever had a heat loss calc on our house, and ask for an official quote for price and what exactly will be done.
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