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Looking for Advice on new boiler system

mdk0420mdk0420 Posts: 5Member
Hello all. New to the forums. I've been researching boilers for the last couple of months. I had some gas lines ran to the home to switch from oil heat to gas heat. I have to make a decision this year or I have to pay for the credit UGI gave me for the line install.

I've been looking at all sorts of boiler types, and I am having a hard time making up my mind on some things... I definitely want a direct vent. By the time I get a chimney vent with the lining of the chimney, it'll cost about the same or even more then just getting a high efficiency boiler.

I was researching condensing combo boilers but I don't like the idea of how I have to drain out the condensation, and being in the basement I would need a pump to pump it up and out. Then I have to worry about the drain pipe freezing. My least likely option, but the prices are cheap and I could sell my hot water heater to get back even more of my money.

Are there non condensing combo boilers? I found a NRCB180DV 180,000 BTU Combi Boiler and no where in the description does it mention being a condensing boiler. But it looks small compared to a heat only boiler. Are they a good option? I would hope that I could take a shower and not experience cold water if the heating system had to kick on lol.

The other option is just getting a heat only HE gas boiler. I had there boilers I was looking at:

PVG3, 52,000 BTU Output High Efficiency Cast Iron Boiler
GV90+3 56,000 BTU Output High Efficiency Gas Boiler
GV90+4 84,000 BTU High Efficiency Gas Boiler

I really don't think I would need 84k BTUs with the Well Mclain. I live in one of my units of a multi unit home, and this apartment is only around 650-700 SQ FT minus the basement. I think 52-56k would be enough for such a small home. The current system is 120k but it used to supply more units before I cut those lines off.

I really like the idea of a combo boiler that doesn't condensate. But again, not sure if the one I posted condensates or not, if it doesn't then I think I might go with that one. But with domestic hot water heating, how many BTUs should you have to be able to take a shower while the boiler also heats your heating water? I thought 180k would be more then enough but I saw some reviews about combo boilers not being good for more then 1 hot water line at a time. Suggestions? Thanks!


  • ratioratio Posts: 1,380Member
    The best boiler to install is the one the installer has the most experience with & has ready access to repair parts.

    Has a heat loss been done yet? You can do a quick reality check with the Slant/Fin app, but at 35 BTU/ft2, which is A LOT, you're looking at around 25k BTUh.

    You really should take the time to do the legwork ahead of the install. Reading reviews is important, but if you have properly sized equipment installed by a competent contractor, you'll be miles ahead in efficiency, reliability, and satisfaction.

  • HVACNUTHVACNUT Posts: 1,073Member
    edited April 16
    700 sq ft @ 52K BTU's is more than 74 BTU per sq ft. You don't need nearly the much. You might need less than 20 per depending on the heat loss calc. Your only going to get those numbers with a mod con and a high turn down ratio.

    How many rooms? Open floor plan? Have you looked into ductless systems and a hybrid water heater?
  • mdk0420mdk0420 Posts: 5Member
    Haven't don't a heat loss calc. I'm doing the install. I don't have the equipment to do a heat loss calc though. Couldn't really find anything that was smaller then what I posted. It seems like all the gas boilers are right around 50k-120k BTUs. I figured it was over kill for such a small apartment. But the 120k unit used to run for 2 units. The upstairs unit is probably around 1000 sq ft or so. Seemed like a lot but that's what was installed back probably 30 years ago lol.
  • ratioratio Posts: 1,380Member
    All you need with the Slant/Fin app is a phone and a tape measurer. Talk to your supplier & see what kind of spare parts he has on the shelf. Spares on hand, big turndown (minimum firing rate), small size is what i'd look for, in that order.

    Do the heat loss so you know what you're up against. There're lots of good people here who can help you overcome the problems that crop up running an over-sized boiler, which you are most certainly going to have, but it's so much easier & cheaper to work around it now as opposed to later.

  • RichRich Posts: 2,446Member
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC 732-751-1560
    Serving most of New Jersey , Eastern Pa .
    Consultation , Design & Installation
    Rich McGrath 732-581-3833
  • bob eckbob eck Posts: 696Member
    UGI in some of their areas have rebates of $1800 combi boiler and $1500 condensing boiler only.
    I believe you can run boiler condensate into sewer if you are using an neutralizer before going into sewer. Check local code.
    Where are you located at.
  • mdk0420mdk0420 Posts: 5Member
    Pennsylvania. I'll give UGI a call about that. I already have a credit from them for doing the gas line. Wonder if they would stack that up. I was doing some research and it looked like all high efficiency boilers are condensing boilers. Is this true? It didn't look like some of the boilers were condensing yet they had an AFUE of 92% or higher, and could be vented with PVC. Like the Well Mclain boiler doens't mention anything about condensing.

    I did the heat loss calculation and it only says I need about 9k BTUs... that sounds a bit far fetched to be honest. My AC is a 12k unit and cannot keep more then the bedroom and partially the living room cool. It starts to fade away and pretty much none existent in the kitchen. I do feel as though even 50k BTUs would be a bit much for such a small unit considering my other home is about twice the sq ft and has a 50k BTU forced air heater that works beautifully to keep the home warm. What furnaces are out there that would fit my needs? I just can't find such low BTU heating systems lol
  • ratioratio Posts: 1,380Member
    9k isn't outside the realm of possibilities; and heating and cooling loads are not necessary the same. Also, the consensus is that the Slant/Fin app runs a little on the strong side.

    That said, oversized equipment is something that happens very frequently, but it needs to be though about during the planning stages (i.e. right now) rather than as an afterthought when things just don't work right. Start a new thread in Radiant Heating titled something like "help with boiler piping for 9k total heat loss". Give details on what you're planning on doing, then ask them to point out all your mistakes. :)

  • mdk0420mdk0420 Posts: 5Member
    I'm trying to keep the same setup I have now. It already has everything setup from the current boiler system. The new parts to the boiler would be determined if a high efficiency boiler doesn't have to be a condensing unit. It's nice knowing I can get pretty much the smallest unit to give me the heat I need, but I still want a high efficiency unit. Just hoping it doesn't have to be condensing so I don't need to run a pump to drain the water out.
  • the_donutthe_donut Posts: 333Member
    If you are good with your cardinal directions, works fine as a sanity check.
  • flat_twinflat_twin Posts: 125Member
    Sounds like you've been reading early modcon horror stories. Don't get hung up on whether or not it's a condensing boiler. Condensate pumps are inexpensive. Freezing condensate lines don't happen when you neutralize the condensate and route them to a waste pipe. The ones that are incorrectly piped outside have the potential to freeze and shut down the boiler.
    The type and amount of baseboard emitters or radiators vs your heat loss will determine whether or not your boiler will even operate in a range that takes advantage of condensing. So what kind of emitters do you have?
  • mdk0420mdk0420 Posts: 5Member
    3/4" copper/aluminum radiator piping. Not sure the total length. I have 5 radiators total. One in the bedroom, 2 in the kitchen/dining area, 1 in the bathroom, and 1 in the living room. Bedroom is fairly long as it wraps around the room probably arounnd 15 feet, living room one is pretty small, maybe about 10 feet, bathroom is about 10 feet, one in the dinning room is about 10 feet and the other one in the dinning room is more like 5 feet. So if I gave a rough estimate I would say about 50 feet plus the return comes from the bathroom so it'll run about the length of the house back (Around 25-30 feet)
  • Jamie HallJamie Hall Posts: 8,021Member
    Thermodynamics 101 -- if the efficiency is over 85%, it's condensing, and it is so well matched to the load and the controls and pumping and all are installed and adjusted so that it really is condensing most of the time.

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
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