Seeking advice on new Buderus oil heating system (Westchester NY)

lynewman

Hi, I am in Westchester County NY, and am considering upgrade the oil heating system in the old house we recently bought (built in 1950s, 2500sqft). The house has two zones for the 1st and 2nd floor, there are two radiators in the basement, and the water heater is connected to the propane tank.
For the new heating system, I prefer Buderus G115 WS, and replace the current water heater with an oil fired indirect water heater. One plumber recommended Heat Flo 50 gallon. I guess this will make it at least 3 zone system (1 for water heater), but I am not sure if the radiators in the basement need to be in another separate zone.
Another trouble I have is, none of the plumbers I contacted has done a heat loss calculation for the estimation of the size of the boiler, and very few of them seem to be very familiar with Buderus G115 boiler. Does anyone know a good installer in this area?
Thanks in advance for any suggestion.

doughess

The most accurate way to find actual boiler load is to log run time, degree days, oil/gas consumption over a period of days. 

Wire a elapsed time clock to boiler solenoid circuit.
https://www.ebay.com/itm/Hour-Meter-General-purpose-120-Volts-AC-rectangular-Without-line-Widiamond-Meter/110675262987?epid=858680470&hash=item19c4c27e0b:g:Gq8AAOxymmJTkKlH:rk:1:pf:0

Log the degree day count at start and end of period. Divide number of degree days by hours run to find degree days per hour. If your design temp is 0 F then that is 65 degree days. Divide that by your dd/hour to find run time required on design temp day. 

Many old homes with boilers sized years ago are oversized because of added insulation, new windows and other improvements.

By logging gallons used during time period, degree days per gallon can be determined. That is what oil companies use to schedule deliveries.

If boiler also supplies domestic hot water the dd/gallon will be slighly higher in colder weather. 

Clocking actual run time data is more accurate than using heat load calculations and boiler/nozzle rates. It is real data. Allows determining actual nozzle gph flow rate. Charts showing flow at different psi show calculated, not actual flow rate

mxfrank

Sloppy installers will just install the same spec boiler/burner rather than doing a heat loss calculation. it's the safe bet, but oversizing will cost you a lot of money over time.

Doing the calculation by measuring run time is very precise. But it usually yields a number well below the firing rate of the existing boiler. This is because the boiler was likely grossly oversized in the days where oil was less expensive. But also because the firing rate shouldn't be cut to close. You want to add a comfortable reserve to ensure setback recovery, and because heat loss isn't always linear with respect to outside temperature. (Cloud cover and high winds can add to the BTU requirement.)

Another question is whether you will have a separate heater for DHW, or whether you're going to use a storage tank. If the boiler will also be supplying DHW, you need to add that requirement to your heat loss calculation.

I'm also in Westchester, and I have a Buderus. I'd be interested if you turn up a good tech.

lynewman

doughess and mxfrank: thanks a lot to both of your great suggestion.
mxfrank: I tend to use the boiler for DHW, so yes that needs to go into the heat loss calculation. I'll let you know if I end up with a good tech.

HVACNUT

At the top of the page, theres "Click here to find a contractor in your area ".
Scrap the guys that came out because a heat loss calculation must be done.
And they're not familiar with the Buderus, so that's not good.
Do you plan on using the R2017 Logamatic?
And why not a matching Buderus indirect?
You can download the Slant/Fin heat loss calculator and do it yourself so you know where you stand but your going to need a competent contractor to not just install but service your boiler for years to come.

Robert_25

I would put the basement radiators on their own zone. Not difficult to do at the time of boiler replacement, and it will give you control of the temperature down there. Also, I suggest finding a good contractor and seeing what equipment they recommend, rather than picking Buderus and then trying to find someone familiar with it.

Robert O'Brien

The smallest G115 is 85k DOE and 74k IBR. I've never seen a relatively standard 2500 sqft home have a heat loss within 20% of that. If DHW can't be handled with that even with a larger indirect, go tankless, don't over size boiler.

KC_Jones

lynewman said:

doughess and mxfrank: thanks a lot to both of your great suggestion.
mxfrank: I tend to use the boiler for DHW, so yes that needs to go into the heat loss calculation. I'll let you know if I end up with a good tech.

No, no it doesn't. If someone does they will again oversize your boiler. I wish people would stop spreading this misinformation.

lynewman

Thanks for the great suggestion here!
It is just so strange only 2 contractors came out from the search engine here, one of them doesn't do residential, and the other is in NJ and wouldn't want to come. Oil boiler is very common in Westchester, and actually there are lots of plumbers out there, maybe most of them are trying to make money (nothing wrong with it) instead of spending a little time to catch up with the knowledge shared here, :-)

plumbbob

plumb rite inc 914 779 7900

rick in Alaska

"The smallest G115 is 85k DOE and 74k IBR. I've never seen a relatively standard 2500 sqft home have a heat loss within 20% of that."
That is why I don't waste time doing a heat loss calc. Unless I do a house that is more than about 2500 square feet, I know the smallest boiler I can get is still too big, so whats the point in doing a calc? It would be different if you were also putting in the baseboard, because then you would need to know how much per room. Or, if you lived in an area where houses are not built well and have no insulation, or very little. Which , now that I think about it, appears to be common in older homes on the East coast it seems. So, just because someone doesn't want to do a heat calc does not make them wrong.
Rick

lynewman

Thanks Rick. I am not sure if people tend to overestimate the boiler size, but when a plumber (who claims to be a "master plumber" ) came a few days ago, he told me that he is going to install a boiler of 150k BTUs after spending 10 minutes in the house without doing any measurement. I hope most plumbers don't do that.

doughess

Logging burner run time gives total, combined building heat and DHW total.

Looking for a good tech or professional is a crap shoot/lottery. Even if they calculate heat load it is still a guestimate.

As other posts mention most boilers are very over sized. Typical run tine time is 20% to 25 % per day, less than 6 hours. If outdoor temp is 30 F, the run time doubled would represent zero degree F design temp.

Spend $!5 and wire a hour meter to burner motor leads.
https://www.ebay.com/itm/Hour-Meter-General-purpose-120-Volts-AC-rectangular-Without-line-Widiamond-Meter/110675262987?epid=858680470&hash=item19c4c27e0b:g:Gq8AAOxymmJTkKlH:rk:1:pf:0

GW

I’m always amazed. So someone spends and hour measuring and quotes you a boiler that’s size A. The next guy walks around and doesn’t scratch one note and then quotes size B... you automatically go with A because he measured? Its like a magic trick. I’ve done hundreds of calculations but now rarely do. I downsize systems routinely. Too big is dumb

Advancedplumbing

Another way to easily size a boiler is to add up the btu load of your heat emitters. If you only have 50,000 btus of baseboard in the house, then it doesn't matter how big you size the boiler. Standard baseboard is roughly 550 to 600 btus per foot when running 180 degree water. I use this method a lot with smaller oil systems as the the G115 only comes in three sizes so you just have to get close. Keep in mind that these boilers are sized for the coldest day of the year. 99 percent of the time they will be over sized anyway.

As far as adding on btus for an indirect, this can be avoided if you run the indirect with priority so that it only runs by itself.

Hope this helps.

HVACNUT

> @Advancedplumbing said:
> Another way to easily size a boiler is to add up the btu load of your heat emitters. If you only have 50,000 btus of baseboard in the house, then it doesn't matter how big you size the boiler.

Yes, the G115-3 would work for most, but the "measure the emmiters" process is not correct.
How is it known if theres too much or too little?
What temp does the boiler need to be at on a design day based on the emitters?

SuperTech

Your best bet is to do the heat loss calculation yourself so you know what size boiler you need. I used to work in Westchester county, I know the quality of work that is usually seen. You will have hard time finding a good company. Download the slant fin app and give it a try.

GW

I've seen homes with twice the required baseboard

When in wide world of sports would a 2500 sq ft home need a 4 section?

D107

HO from Westchester. I'd recommend Anthony Pici Plumbing and Heating http://www.ap-ph.com/ Met him a few times, seems to know his stuff. Been doing this for many years.

lynewman

Happy New Year to all, and thanks for all the responses, they really helps me understand.

Some update. I got a quote from a plumber with the following:

"Existing house 1056sf semi finished basement, 240sf unfinished basement, 1296sf first floor, 1056sf cape second floor=2352sf living and 1296 basement. 2353sf x avg 35BTU/SF=82,320
BTU/HR required. Proposed 45 Gallon indirect boiler Superstor recommended size 141,000BTU/hr, Buderus
G215/4 boiler @ 149,000 BTU/HR net rated 86.2% AFUE."

I asked him two questions:
1) Any advantage of G215 over G115 model, which he didn't reply immediately yet;

2) If the boiler size is oversized, and his response is: "As far as the size, yes, boiler is a little larger than needed for the heat load, but meets the minimum recommended boiler size for maximum output of the indirect water heater." Does this sound reasonable?

rick in Alaska

No! First of all, a heat loss will tell you the actual heat load, not an arbitrary 35 btu/square foot, which sounds way high to me anyway. Second, you do not size the boiler for the hot water load, just to the heat load. Typically, you figure how much your hot water usage needs to be, and size the tank to it. What usually happens is you have, say, a 45 gallon tank with a mixing valve on it. However if you have a bigger load, you might go for a bigger tank, or even run your 45 gallon tank at a hotter storage temperature and then just mix it down to 120 degrees. This will make the smaller tank act like a bigger tank.
I believe the model number for the Buderus you probably need is a G115/3. Which is still usually too big, but I believe is the smallest they make.
For reference, I have a 175,000 btu boiler heating an older 6 plex apartment building which is also heating a 120 gallon water heater. This has been working fine for quite a few years now with no issues. So, do not let them put in a 141,000 btu boiler! Unless of course, your house is not insulated well and the heat loss calculations support it.
Rick

lynewman

Thanks a lot for your suggestion, Rick!

GW

OK now this is getting out of control- a G215 in a normal-sized cape? Get some more quotes.

Ironman

I've got a house that my sister in law owns that's 5 times the size of yours and it has a g215/4 heating that we put in it 12 years ago. Parts of the house date back to before the civil war and it leaks like a sieve. No insulation, old leaky Windows, solid brick walls 16" thick. That boiler heats it fine.

I have been doing load calcs for almost 40 years and I have never seen a house that needed more than 32 btus per sq. foot. Even that one.

The load on your house is probably less than 32k btus.

Get rid of the clown contractors.

lynewman

Thanks, Gary W and Bob B, and other responses.
Robert O'Brien and rick in Alaska and many others have mentioned earlier that 85k BTUs would be more than enough, and I am glad to have all your quick response/suggestion to help me interview the plumbers.
Another question I have is how to choose the right size of indirect water heater that is supplied by the boiler, and how it is matched to the boiler size. I know folks above suggested set the water heater as priority, and rick in Alaska's suggestion seems to indicate the water heater size doesn't matter much as long as you can adjust the temperature setting of the heater if I understand correctly.

Ironman

I honestly can't tell how many houses I've done with a 32 -40 gal. indirect and an 80k btu boiler and I've never had one complaint about a lack of hot water. Some have had large families like mine (6 girls + 1 boy).

A standard 40 gal. gas water heater usually has a 32k btu burner. You would have 2 1/2 times that much horsepower.

HVACNUT

I knew a guy who sized boilers by how many zones there are.
He inspected for an oil boiler replacement in a small dwelling on a church property.
The company I was with at the time had the techs, any tech, fill out the required survey sheet.
Existing boiler, firing rate, #zones, access, man hours, "bring the big wheels", etc.
Then the techs replacement boiler recommendation, pipe, controls needed, etc.
The place couldn't have been more than 1,000 sq ft. all on one level.
But, each of the 4 bedrooms had it's own zone, plus the main zone and indirect.
So obviously the place needs a WBV-4 Peerless, well, because its 6 zones and the old boiler was firing at 1.25.
So, duh.
Buderus was the other brand we offered so I had to ask, why not the G215/4?
If I mentioned micro zoning or ODR, his head would explode.
Sadly, the company didnt want anyone there long enough to do a proper heat loss on any survey. I talked to the Service Manager about it. It didnt go well. Shame.

lynewman

One more update from another plumber on the proposed work:
"Furnish and install a Buderus G115-4 boiler complete with a Riello F3 oil burner, tiger loop with spin on filter, #30 extrol expansion tank, 911S feeder backflow combo, (One) 1- 1/4" spirovent air eliminator, new flue pipe to chimney base, (Three) 007 F4ECM circulators with isolation flanges on supply and (Four) zone Argo relay panel. We will build supply and return manifold with isolation valves and common purge on return. Comes standard with Hydrostat 3250 plus. This proposal includes
a Vaughn 50 GAL Indirect Hot Water Heater and changing bleeder keys on radiators."

G115-4 might be over sized according to earlier replies from folks above. My other questions for experts on this forum are:

1) How is Hydrostat 3250 plus compared with Logamatic 2107 control? They offer this option with a significant premium.

2) How is the quality of Vaughn 50 GAL Indirect Hot Water Heater? I didn't see many reviews online, and most other plumbers recommended SuperStor 45 gal indirect water heater which is stainless steel.

GW

Yes that’s a prettty normal write up

The contractor may be fabulous or horrendous

Just look at their online reviews

2107 is a nice control but many people are absolutely clueless on how to set it up, I kid you not.

How big is your home? Most of our installs are 3 section

JohnNY

3 Years ago I started making an effort to transition out of contracting and into heating system consulting and design. It's mostly troubleshooting for residential buildings and creating repair and maintenance schedules for larger buildings in and around Manhattan. But once the phone started ringing, I realized most of my residential calls were coming from Westchester, NY. The work being done and the guidance being given in that area is oddly subpar. Everyone, one after the next, tells me they can't get anyone decent to work on their steam or hydronic heating system that seems to know what they're doing. Everyone wants to convert them to forced air.
There seems to be a flat spot of mechanical talent up there.

Consulting work alone is still somewhat seasonal, so I'm still contracting in the areas where I'm licensed (NYC) and carry a 10-million-dollar insurance policy to perform gas work and perform complete installations, but if you think I can help you, feel free to reach out.

JohnNY

GW said:

2107 is a nice control but many people are absolutely clueless on how to set it up, I kid you not.

Agreed. The only problem with the 2107 is that it's got a language all its own. There's an umbrella button. There's a suitcase button. Whaaaat?
Once you read the manual, though, it makes sense.

GW

yes reading is 1/2 the battle. We have a guy with a Viessmann WB2B (he wants 'more heat' in a certain zone) and setting up the 'external demand' is a bit of a pain. The manual is brutal. Once you can creep into the brain of the engineers that designed this stuff, you're all set.

Ironman

@lynewman

You won't find any better than johNY. I'd recommend that you contact him asap.

JohnNY

Ironman said:

@lynewman

You won't find any better than johNY. I'd recommend that you contact him asap.

Thank you for your confidence in me, Ironman.

lynewman

Thank you all. will reach out to @JohnNY.