BTUs

Mattera

I've started to discuss replacing my less than dependable boiler with a local oil heating company. My current boiler (Burnham RS111, Becknett Burner R4184 D1027 and 2 Taco Circulators 007-F5 was installed at least 25 years ago when there were much fewer baseboard heating units. The house has been through major renovations in the past 20 years which increased the baseboard heating to approximately 225 feet which includes the addition of the 3rd floor. How do I determine how many BTUs are needed? So far it was suggested that I use the existing number of BTUs (unknown to me) on my current boiler and the increase in baseboard heating will not affect the BTUs as all three zones will not be calling for heat at the same time. Is this correct? The thinking is that the house has adequate heat but I rarely heated both and the 1st and 2nd floor unless it was very cold in the northeast and now I've added a 3rd floor. The 3rd floor heat would not be used daily. I It had also been recommended that I install a Williamson boiler as opposed to a Weil-McLain, 1 circulator and zone values. I had thought I would be installing 3 circulators and can't help but wonder if 1 circulator for all 3 zones would wear out quicker and be more susceptible to breakdowns. Please help, all and any information is greatly appreciated. I would like to purchase and install no later than next month. Thanks.

Robert O'Brien

You need a heat loss calculation.

Mattera

Thank you, Robert, this was discussed briefly when accessing the needed replacement and the installer felt it was more than what is necessary due to cost and time involved. He has been installing heating systems for 30 years and doubted that I had 200 feet nor did I need it but I measured after the meeting and I definitely have the 200 ft. I have replace all windows and exterior doors. The windows on the 2nd and 3rd floor are about 15 years old now, certainly not as efficient as the newer windows on 1st floor. Thanks again.

Paul S_3

you can download the Slant Fin app on your smart phone and do a room by room heat loss calculation like Mr.Obrien recommended. If you are worried about breakdowns a grossly oversized boiler would cycle itself to death.....you want to achieve long run cycles with a properly sized boiler. Where are you located? Have you used the "Find a contractor" section on this site? Theres some real professionals here.
P.S anyone that told you to pick your new boiler from the output of the old one, you shouldn't use them.

SWEI

How big is the house, and when was it built?

Mattera

The house was built in 1900 and is in Cape Cod. It has been renovated which included replacing the insulation and adding sheetrock in addition to new windows and exterior doors. The house is about 2200 to 2400 square feet. I found this website after my meeting yesterday with the oil replacement people so I didn't use the FIND A CONTRACTOR on this site... will check out... thanks. Will also check out the Slant Fin app today. Thank you, please keep ideas and thoughts flowing. Never replaced a heating system before... had electric heat.

JUGHNE

If you post a picture of the nameplate of the boiler and another of the nameplate of the burner, someone here will know more of your situation.
I don't do oil anymore, but usually there is a range of firing capabilities for burners by changing the oil nozzle size.
That size determines the actual capacity of the boiler. Service records may tell you the nozzle size. I used to find used ones left at the boiler/furnace....that would be an possible indicator.

I might go out on a limb here and say that most of us have seldom come across any boiler/furnace that is too small for the job.....especially if your additions were adding floors/stories upwards and if your thermal envelope has improved. IMO.

Mattera

I have the oil boiler manual and this information maybe helpful ...
Burnham Model - RS111
Bare Boiler Assembly - WV18-9A
DOE Heating Capacity BTU Hr. - 120,000
SBI Firing Rate, GHP - 1.05
SBI NET Rating, Water BTU/HR. 104.300
SBI NET Rating Water SQ. FT 695
Piping & Pickup Factor - 1.15
Standard Coil, Heating Boilers - #7524
Standard Coil Rating, GPM - 3.25
Optional Coils, Heating Boilers - #7530

If you need more information I have items such as tube diameter, chamber material, heating surface, value capacity, nozzle size and much more.

Beckett Oil Burner - Model AF
0.40 to 3.00 gallons per hour
56,000 to 420,000 BTU/HR input
Number 1 or 2 fuel
Standard Dimensions
Height 11 1/2" Width 12 7/8" Depth Chassis Only 6 9/16"
Electrical Power 115V/60 Hz 1 PH
Operating Load Max. 5.8 amps
Motor 1/7 HP, 3450 RPM, N.E.M.A. "M" Flange, manual reset Overload protection
Ignition 10,000 V/23 ma secondary. continuous-duty shielded, transformer of solid state ignition system
Fuel Unit - Sundstrand or Webster

Please let me know if you need additional information, I don't see much info on the face plate. If I'm looking at the correct plate. Thanks again.

SWEI

Hatterasguy said:

An insulated 2400 square foot house in Cape Cod won't have a heatloss above 70,000 BTUH on the coldest day of the year. It probably will be less if the infiltration loss is not horrendous.

Thus, for an oil-fueled boiler, you need the smallest size made regardless of brand. As Brian pointed out, downfiring the existing boiler may be your best bet. I would suggest an iSeries-R mixing valve and constant circulation as well.

Mattera

It has not been reliable since February. I have to hit the reset frequently and sometimes it will be OKAY for a few days and other times it will start up and run after hitting the reset for a few minutes only and that's all I can get out of it for 4 or 5 days. For some reason it is not recognizing the flame. I also had problems the winter previously to the last one but was able to get it repaired. My current oil company which is very expensive has been recommending a replacement for several years. I'm trying to get other opinions and quotes. Thanks for your advice and for sharing your thoughts regarding BTUs. This site was been very helpful. I also used the FIND A CONTRACTOR section and there are no recommendations within 100 miles.

SWEI

As long as the boiler castings are intact, it's probably saveable. @Robert O'Brien works out of Mt. Sinai and is more than qualified to do this right.

JUGHNE

Does the oil company offer "Free clean and check"? If so how long does it take them to do this?
It would be interesting to see the inside of the burner/boiler.
Remember if you sell the fuel, your interest is to just keep the burner running, regardless of efficiency. I think they would never recommend downsizing the nozzle size to burn less oil and give you a longer run time.
Changing the entire burner would insure no nuisance call backs for probably 3 years of neglected operation. (I would guess that the burner replacement is not part of the "Free clean & check") .

JUGHNE

I was very glad to replace the last oil burner furnace in my area with gas. Oil service took a minimum of 2 hours. Some neglected ones were almost an entire day of cleaning. I often felt I was the first one (the young fool) to clean the heat exchanger after 10-15 years.
15 minutes would get the air filter changed, look at belts, oil motors, maybe change oil filter. Look at nozzle....no way.

Mattera

Thank you for the information... I have a lot to consider after reading your thoughts and suggestions.

Steamhead

I'll second/third/fourth the above. If the installers won't do a heat-loss calculation, fire them. They don't know their business. Maybe you could get away with that in the pre-computer era, but there's no excuse for it now.

Robert O'Brien is one of the best, but if you're on Cape Cod the travel time might be a bit much. He's on Long Island. Here is our Find a Contractor listing for Massachusetts:

https://heatinghelp.com/find-a-contractor/state/MA

Paul48

Try Rhode Island

SWEI

Mea culpa. I don't know where Long Island came from.

Paul48

RI--Steamworks?

Mattera

I've continued to research and the most recent recommendation if I decide to replace as opposed to repair is to install a Williamson OWB - 4 85% AFUE, 145,000 BTUs, with a Beckett AFB burner and 3 TACO zone values. feed valves, air scoop, purge stations, relief value, smoke pipe, extrol tank, shut off values and update the oil line. Any thoughts? Thanks.

spoon22

Bill two case is on cape cod he is on here.Not all oil companies do crappy work I am in ct and my company uses efficiency equipment and are more interested in saving oil customers gallons because it is not all about gallons it is about how many customers you have. A 25 year old burnahm steel lived a good life a modern 3 pass boiler with odr will save alot of gallons over an rs111

Mattera

In reviewing the difference between the OWB-3 and 4 it has been pointed out to me that with 220 feet of baseboard, if all 3 thermostats/floors called for heat at the same time I would be better off with the OWB-4. Although I think that is unlikely it is possibl . The recommendation is to install a Williamson OWB/OWT Series 2 which works on demand. I thought all boilers worked on demand, is that not true? Thanks.

Robert O'Brien

The amount of baseboard is absolutely useless information in arriving at a properly sized boiler. The heat loss of the structure is the only thing that matters.

Robert O'Brien

This will put you within 10% of the number and in the oil boiler world that is all you need.

http://mechanical-hub.com/sites/hydronics/heat-loss-calculation-on-every-residential-boiler-replacement/

Robert O'Brien

And no, most oil boilers maintain temp 24/7 and do not run
"on demand". I wouldn't buy one of those.

Mattera

Can you please explain the difference between 24/7 and on-demand? It would seem that with ON DEMAND once the temp falls bellow the desire temp a call would be made for more heat. Isn't that basically the way it works... so how is 24/7 heat any different? What are the advantages and disadvantages between them? I've always had electric heat before moving here. I think you are right and the only way to determine the correct and efficient size of the boiler is to do a heat loss calc.

Robert O'Brien

Oil boilers with tankless coils must maintain temperature. Even when installed with an indirect they are commonly maintaining temperature although it most cases they don't have to. The alternative is called cold start which means the burner only runs on a demand from a thermostat or the indirect. This the preferred arrangement and allows the use of a triple pass boiler which are easier to maintain and have no coil gasket to fail as well as being available in smaller sizes
than pin type coil boilers.

Mattera

Earlier you said you would not go with ON DEMAND and now it seems like you are saying the cold start/on demand is the preferred arrangement. I'm confused... perhaps I misunderstood. Can you elaborate? Thanks.

Ironman

No, he said he would not go with a boiler that had a tankless coil because it stays hot 24/7. They're real energy hogs and I don't know of any pro on here that would recommend one.

Mattera

Thanks for clearing that up.