Replacing 17 year old oil fired boiler/need help

gmwoodstock

My boiler Peerless boiler, pretty inefficient I suspect, started leaking and needs to be replaced. I've received wide ranging advice from local installers. One is suggesting Carrier/Dunkirk BW4 w/ Honeywell basic control, or for a very large upcharge, a Honeywell AQ control that measures outside weather and increases efficiency. This guy does not also sell oil.

The other is suggesting, for lower price, Crown Tobago TWB 150k BTU and says that not much can be done to increase efficiency with a controller. This guy sells oil/may not be invested in helping customers increase efficiency.

I'm willing to spend more now to save long term, but do not know if I'm being miseld. Any help would be appreciated.

mattmia2

Is this hot water and not steam?

gmwoodstock

hot water

mattmia2

Those are decent but low end boilers, they are perfectly fine but not the most efficient. The more efficient boilers that are available in oil are Energy Kinetics, Viessman, and I think certain Peerless models. There may be a few more but the more efficient models have a multi pass HX design of one form or another. You might gain something like 5% to 10% over your old boiler assuming the old and new boilers are set up to not short cycle. If the old boiler was oversized or set up improperly you might gain more efficiency if you size the new boiler more closely to the loss of the house.

The modulating, condensing boilers are only available in gas so the most efficient boilers are not available in oil.

What kind of emitters do you have? Are they cast iron radiators or fin tube baseboard, or convector cabinets or radiant tubing or what?

Jamie Hall

Has either of these folks done the basics? Step one. determine the actual heating demand of the structure. How many BTUh do you actually need in the coldest weather. Step two: measure the size of the radiators or baseboards in the house.

Step one will give you the size of boiler, in terms of BTUh, you actually need. It may not be as much as you think. Or as much as you have…

Step two will tell you what temperature the boiler needs to run at.

Until those two steps are done there's no point in trying to determine what boiler you might find useful…

mattmia2

https://forum.heatinghelp.com/discussion/comment/1859813#Comment_1859813

Except if you want to use oil you are limited to conventional boilers of some flavor.

gmwoodstock

Thanks for these quick comments. We have 40-year-old baseboard emitters with the metal fins.

Neither determined how many BTUs needed or looked at the baseboards. These are local, family HVAC operators who seem to be offering what they want to sell (which I assume they get at bulk discount from their corresponding usual manufacturer) as opposed to right-sizing the boiler to the house.

That doesn't bother me that much. I don't need to squeeze out every efficiency percentage available, and I'm ok with a lower end boiler (at a lower price). Just don't want to overspend to get something lower end.

Also, any chance that a computerized controller on the Carrier/Dunkirk could substantially reduce inefficiency — 30-40%? That's what the first guy said to try to get us to go for his upcharge item.

hot_rod

what does effect efficiency is an over sized boiler!

An 87.% boiler could run in the 70% range if it is too large and short cycles

Knowing the amount of fin tube is useful, but a heat load calculation gives you the best answer

HVACNUT

You want either a cast iron 3 pass boiler, or a System 2000 by Energy Kinetics. Outdoor reset is useless on an oil fired system that isn't piped for it, with a buffer tank or high mass piping and emitters. Which you dont have. And oil fired boilers use an operating control that doesn't modulate, but fires to limit, whatever that limit may be.

You should have a heat loss calculation done, even though the smallest oil fired boiler is too big for most homes up to 3,000 sq. ft. if you consider a 75K BTU net. That gives you 25 BTU per sq. ft. For 95% of the heating season, that's too much. Unless you see sub zero temperatures often.

Honeywell, Hydrostat, and Beckett all have operating controls with economy settings that work well without using Outdoor Reset.

I don't recommend either of the boilers offered unless there's space or cost issues. They're both pin HX boilers. If space is the concern, Buderus offers a stackable G115 over their indirect water heater, and System 2000 offers the Frontier on a pedestal with their water heater underneath.

mattmia2

you can also usually downfire an oil boiler a bit to help with the smallest boiler being too big.

EBEBRATT-Ed

If its oil most boilers are around 84-85% no matter which one you pick.

I would say EK is top of the line. The rest of them don't differ much.

If someone told you a control would save you 40% that's salesmen talk which is good for 0

You need a heat loss done.

Then find the best installer you can and let him pick the boiler

EdTheHeaterMan

How does an oil fired, cast iron boiler end up needing to be replaced in 17 years?  Someone made a big mistake when it was installed in order to have it go bad so soon.  If the old boiler has a tankless coil for DHW, then the gasket bolts were never torqued after the first 500 hours of operation.  That can cause the gasket to start to leak within the first 4 years of operation.  Once that rust starts to build up then there is no going back at year 17.    

Make sure you read the I/O manual when you get your new boiler to see if anything was overlooked by the installers.  Also, get the combustion test numbers in writing from the mechanic/technician that does the initial start up. 

I also like Energy Kinetics for the best overall operating efficiency of an oil fired boiler system. Their gas boilers are also pretty good too.  there may be some sticker shock from the EK installer, but that will wear off quickly when you see the fuel usage drop.

Robertw

All great advice, thank you everyone. I would like to remind you of the ascent plus side wall vented oil gas or lp fired combi boiler we offer. Its low mass (3 gallons) and can deliver up to 4 gpm of hot water at 67° rise. We offer this as low as 86k btu's to 123k btu's for oil and 73 k btu's to 135K btu's for gas or lp.

Small footprint no tank, Great efficiency and lower cost.

Feel free to reach out to our national sales manager to get more info as well as in touch with some factory trained dealers in your area. 570-872-6997

gmwoodstock

You have all been very helpful. Thanks. The local installer who initially recommended the Crown Tobago TWB 150k BTU, when I asked about 3-pass option, says his supplier has a New Yorker CI-HGS-123E-LBBH. I did not see New Yorker mentioned in the comments above — does anyone know if this is a good one?

Thanks!

EBEBRATT-Ed

Crown, New Yorker, Burnham and Force are all the same. Made by US Boiler Company which is Burnham

Steamhead

https://forum.heatinghelp.com/discussion/comment/1860027#Comment_1860027

Same block as the Burnham MPO, which is a nice boiler.

rick in Alaska

You better have a very large house if they think you need 125-150k btu. Or no insulation. Do your own heat loss before doing anything. As an example, I put a 175 k btu in an older six plex apartment building, and it is also feeding a 100 gallon water tank. Do not oversize your boiler!

Rick