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Bosch Greenstar combi

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MikeG
MikeG Member Posts: 169
in THE MAIN WALL
It's been a while since I posted. Looking for some feedback on the Bosch Greenstar boiler. I'm in Ohio but my son lives in New Hampshire. His peerless boiler is shot and the installer he contacted recommends the Bosch floor mount 100K. This will be on LPG. His domestic water heater is still working fine. The installer said he could add the domestic part later. I don't know if he recommended the floor mount for ease of install or not. Right now they have no heat, wife, three girls, 9, 6 and one month old. Looking at 2-3 weeks if he says yes soon. I'm not that familiar with these. Trying to read over the manual. I put in a Munchkin with an indirect. Looking at the info it will go down to 24K. Hi s house is only 1100 sq ft with full basement that will be finished. Finned BB. This installer says he has installed a lot of them. Does this work like a tankless in DHW mode. Can an indirect be added? Just trying to get some info to help him decide. Thanks in advance. Mike

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  • kcopp
    kcopp Member Posts: 4,432
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    Where in NH?
  • MikeG
    MikeG Member Posts: 169
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    Lee NH
  • kcopp
    kcopp Member Posts: 4,432
    edited October 2019
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    I am 2 two towns over from Lee.
    Is the current Peerless boiler LP gas fired?
    Just about any boiler can have an indirect WH added to is.
    Most boilers have a combi version and a heat only version.
  • lchmb
    lchmb Member Posts: 2,997
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    I've installed a number of these.. Very easy to install, prepiped for primary/secondary. Easy to set up combustion. all and all an excellent unit. Most of mine have been in for a few years with no issues.. Maintenance is key to any condensing unit. Make sure it's cleaned and tested with an analyzer yearly.
  • GW
    GW Member Posts: 4,692
    edited October 2019
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    Don’t get why people love the combination, especially in a small home. The unit will cycle like a dog unless it’s 15 degrees or colder. Just get a heat only and add an indirect down the road. If you want cheap, then sure.

    Floor mount for faster labor—if you want a wall mount just say you want a wall mount—no prob.
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    gary@wilsonph.com
  • MikeG
    MikeG Member Posts: 169
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    Kcopp, yes the Peerless is on LP. The installer who came out to look at he Peerless, recommnded the combi. My concern is that the 100k is bigger than needed. Right now his existing LP dwh is working. I personally would go the indirect route later if needed. Some conflicting info I saw was a turn down of 4:1 and then I saw 5:1. I suppose the floor mount was pushed because of easier install. This installer indicated he had better experience with the floor model versus the wall mount. Space is not a real big factor. I don't want this thing to short cycle and negate the efficiency in the long run. LP isn't cheap in that part of the world. I pay $1.15 right now in NW Ohio. With the combi what is needed in the future for DHW? I am I understanding that it has a flat plate HE. So a circ and control package. Then would that just tie into the existing distribution system? So in effect in DHW mode it is like a tankless. I had an Aqua Star in my house for nearly 20 years, standing pilot 140K BTU back in the 80s. No real issues, but I like my indirect better. I track my LP and I don't use any more than before, and no issues with cold water sandwisch. The DHW output was only around 2.65 from the specs on the Greenstar. I wonder if a future indirect would be better.
  • kcopp
    kcopp Member Posts: 4,432
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    Where he has 3 young ones who will use A lot of hot water in the coming years then an indirect is the way to go. If the current tank is working then you have the time to squeeze as much life out of it as you can.
    I would do a LP gas boiler Heat only. Then do an indirect later. You need to see if the baseboard and heatloss to the house match up for a 94+ boiler. May or may not.
  • GW
    GW Member Posts: 4,692
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    He said 1100 sq ft. Probably 25000 btu.
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    gary@wilsonph.com
  • MikeG
    MikeG Member Posts: 169
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    I know an indirect specs a certain amount of horsepower to run it. I put the Munchkin M80 in my house with an Amtrol 40 gal indirect. I piped it as another zone. There are 4 other zones with circs . I sued close tees off the boiler. I have mostly BB with a zone off copper under a slab and some ceiling radiant. Of course there are only two of us now but we never have an issue of no hot water. I only run max 155* off the boiler for everything but the radiant. My concern is having something way too big. I could have gone smaller in my old farmhouse. I know my son syas his house needs windows and he feels the house is probably not as well insulated as i should be. I would be leaning toward a heat only boiler with an indirect for the future. How much different is that than a combi with a flat plate. The house may need the 180* water on the real cold days, but I'm not sure a 100K BTU is right.

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