Excessive Fuel Usage; Utica 175 MBTU Boiler Too Big?

NTL1991

Hello. I'm trying to help my parents out with their heating system. They claim they've been blowing through heating oil for some time now, and I'd like to find out why, and fix the problem once and for all.



They have a 2,134 square foot 2-story home here in Rhode Island. Their heating system is hot water with fin-tubed baseboards. When they purchased their home in the mid-1960's (the house was built in 1820), it was completely gutted, renovated, and insulated to the standards then. The only thing kept were the 4 exterior walls.



The first floor, about 900 square feet is on zone 1, the second floor, again, 900 square feet, is on zone 2, and their 29'x14' year-round attached patio room is on zone 3. The Boilermate is zone 4.



Their domestic hot water was supplied (until about October last year) through a hot water coil in the furnace. Now, they have a 41-gallon Boilermate indirect-fired hot water tank



I've been helping them out with their oil bills for a while now, and they burn about 150-175 gallons of #2 heating oil every month during theheating season. Every zone has a programmable thermostat. Zone 1, and Zone 3, the 1st floor and patio room, are kept at 67 degrees at night. The 2nd floor (Zone 2) is kept at 60 degrees, and never calls for heat. (The heat that rises up the staircase is just enough for them... They don't like warm bedrooms).



They said that they never had a problem with the boiler burning this much oil. The boiler sprung a leak about 12 years ago, and my brother, who services burners and installs boilers for a living, replaced it with a new Utica SFH-4150W. The DOE capacity is 175 MBTU. According to the inspection sheet that was filled out in 2001, the burner (a Beckett AFG) nozzle is a 1.10 at 80 degrees. (The plate says the nozzle furnished with the boiler was a 1.25 at 80 degrees) The Gross stack temp was 500 degrees, and the net stack temp was 450. There was 14% CO2 and 0% smoke. The overall efficiency was 83.75%. See attached image. They had a problem with their hot water. When you would open the faucet in the basement (or any hot fixture in the house), the burner would immediately kick on, run for about 5 minutes, and kick off. This would occur in the summertime too. My father would complain that in order to take a hot shower, he would have to turn up the temperature on a thermostat. If not, the shower would be boiling hot one minute and ice cold another. Th Boilermate solved most of their problems with hot water notkicking the boiler on, but the problem is that the tank gives off it's heat rapidly in the cold, unfinished basement, which kicks on the boiler to heat the water in the tank. All year round.



I did a quick heat loss calculation on their house, and assuming they have even very modest insulation (which they do), the total heat loss was 55,200 BTU/HR.



Also, it should be noted that a Beckett Heat Manager Fuel Economizer has been installed for about a year and a half.The house gets toasty warm, has enough radiant area for the amount of heat loss in each room, and is insulated. I just don't know why they have been burning so much oil with this new boiler.



On the tag, the breach draft was -.03",and the overfire was -.02". An interesting find, however, was the fact that the damper was forced open with a sheet metal screw through the bottom of the damper... Why would someone do this? The chimney is old, but it has a good draft... Without having a manometer, is there any safe setting I can adjust the damper to? I know it should be closed when the boiler is off, and it should flutter around on a windy say, correct? See picture.



The aquastat is set to 200* high (which seems quite high to me, considering the fact that every room has plenty of radiating area...), and 140 degrees low. The differential is set to 10 degrees. Perhaps someone bumped up the temperature of the boiler to compensate for the domestic hot water problems and never put it back down after the Boilermate was installed?



Just a side note, 95% of the exposed boiler piping is completely insulated. Some of the near-boiler piping isn't butthe horizontal runs throughout the basement are all insulated.



Is their anything I can do to reduce the fuel consumption? Can I drop the low limit on the boiler, or even convert it to a cold-start? Can the 200* high limit be reduced to a normal 180*? Would it be safe the adjust the barometric damper to -.02" without a manometer?



Thanks



<img src="http://i12.photobucket.com/albums/a212/NTL1991/Grove%20St%20Boiler/0223111437.jpg" width="480" height="640" alt="" />

<img src="http://i12.photobucket.com/albums/a212/NTL1991/Grove%20St%20Boiler/0223111440.jpg" width="480" height="640" alt="" />

<img src="http://i12.photobucket.com/albums/a212/NTL1991/Grove%20St%20Boiler/0223111437a.jpg" width="480" height="640" alt="" />

<img src="http://i12.photobucket.com/albums/a212/NTL1991/Grove%20St%20Boiler/0223111439.jpg" width="640" height="480" alt="" />

<img src="http://i12.photobucket.com/albums/a212/NTL1991/Grove%20St%20Boiler/0223111441.jpg" width="480" height="640" alt="" />

<img src="http://i12.photobucket.com/albums/a212/NTL1991/Grove%20St%20Boiler/0223111441a.jpg" width="480" height="640" alt="" />

CMadatMe

Your not going to like it

Boiler is too big and you can do what ever you want to it and it won't do you any good. Best investment of your parents money is in a new boiler properly sized and of the 3-pass style. Viessmann Vitorond 100, Burnham MPO would be my boilers of choice for a baseboard application. Would also get the boiler running on outdoor reset.

billtwocase

also

you need to include the BTU's for your indirect. Yes it is too big, but you left out you load for domestic hot water. You can drop your limits down. 110 for your LO limit, 180 for your Hi limit. Also is the coil isolated from the system?  Looks like it, but can't tell. If it is open, and being used as a pre-heater, the burner may can and will fire off, as the cold water entering the coil will transfer to the control well.I would also calculate the degree days, and compare it to previous years. This has been a consistently cold winter this year, and you are not alone when it comes to higher than usual consumption. 

o311sta

I 'm not an oil man

But I would see about down firing it some more.

try setting the differential to 25 as well.

I am in Ma (not far) and 175 gallons from the new years to February doesn't sound out of whack.

Ohh yeah  if it hasn't been cleaned/serviced since 2001    you might want to do that as well!

icesailor

Utica too big:

HVECCA is right. It's too big.

On the other hand, if I was asked to look at it, and having an ancestral heritage from the northern end of the British Isles, I'd at least try to make it better than it is. And you can make it a lot better.

Turn the boiler controls down. Set the "HI" Hi Limit to 165 degrees. Set the "Low" Low Limit/operating control to 140 degrees. Don't make it a cold start, in my opinion. It will make a whole bowl of Kibbles and Bits and plug the boiler up. A warm start will stop condensation. Chances are, you have way too much radiation in the house and it was designed designed for 180 degree water but when you over radiate, it is the same as designing with lower system temperatures. Therefore, you can run the system at a lower temperature. You can always turn it up 10 degrees if you need to if you notice the rooms not heating up. Depending how careful the system designer was will determine if the system will be balanced. The fact that it is all zoned will help.

The screw in the draft damper is probably a mistake. You are supposed to use three screws in sheet metal. That screw is at 6 O'clock. There are probably two more, at 2 O'clock and 10 O'clock. The bottom one was put in instinctively and the installer may have not known that the damper would hang up on it. I never put a screw in the bottom because of hang ups. Any screws below the damper pivot can hang up. You can swap it out for a shorter screw.

The stack temperature is too high, So is the C02. When I set them that high, I usually end up sooting up. That's my preference. But I try to get it down to 450 gross, 400 being ideal. You are in RI. If you have a lot of wind, you may need a second RC to help out when the wind is blowing the rectal orifice out of a cow. And it (the boiler) may not be sealed up that much from cleaning. It may not be all that clean. It sounds to me like the flue ways are not all that clean. I don't know how that boiler cleans. I cleaned one the other day for the first time and the top had never been off. Only the side. There was over an inch of solid soot on top of the sections.  This boiler was one I had seen, I do the plumbing and a heater does the heat. The owner asked me to take it on. There were no holes in the stack. The heater guy doesn't do combustion tests. It was running at 70.5%. I got it up to 81.75%.

Or you can spend some serious cash to get it better with a new one.

When was the last time it was seriously cleaned and adjusted? If the numbers stay up, I'd be trying a 1.00 GPH nozzle 

Brad White

Like strapping a jet engine on a canary.

That said, your heat loss on a per SF basis is not bad, under 26 BTUH/SF.



If I take your calculated 55,200 BTUH heat loss, assume 5500 heating degree days (Providence data, actually Warwick and an average), and an outdoor design temperature of 10 degrees with an indoor design temperature of 67, and 70% seasonal efficiency, I get an annual consumption figure of 783 gallons. How does that sound in total for a season? That is 4.5 months at 175 gallons per month.



Put another way, a typical January might have 1,100 heating degree days. A month like that would burn 156 gallons, right about in line with what you are estimating. This is heating only, so add in domestic usage (less than it was with a tankless coil before), and that might add another half gallon of oil per day, depending on usage.



You might be able to pair that down a bit, but overall, it does not sound horrendous. I mean, yes, the cost per gallon is up, but are you really using more of it? Or does the cost just make it seem so?

CMadatMe

Domestic

You don't add the indirect to the boiler load. This is oil so you could get a boiler that nets out in the 80's, mid 70's and still may be able to take care of the domestic need. If you need 2 back to back showers a 40 gal on 80K will do it. Also your domestic zone should be on a priority zone so if there no zone control was used then add one. By down firing the boiler and decreasing the high limit as Ice has said will provide you some relief but you can't get away with the fact that the boiler is making 3 times and possibly 2-1/2 times if downfired the btu's that are needed to heat the home. Never mind the small zone loads.



Best investment is a new boiler sized properly and put on outdoor reset.

billtwocase

Why not?

Why wouldn't you factor in an indirect? 

CMadatMe

The Indirect

I don't add them because I put them on priority. A zone control w/priority cost miles less than an oversized boiler plus it's wasted fuel usage.

billtwocase

I'll agree

if they are on a priority zone yes. This case it isn't, No question the boiler is oversized, but less oversized if you factor in the indirect that is not on priority in this house. I would be firing the 1 GPH, correct the draft control install as Ice has mentioned, clean the thing, and set it up right. This will help some. Sounds like financially right now a properly sized boiler is not in the cards? I'd go EK-1

CMadatMe

I Kinda Disagree

I understand your thoughts and applying it to this application. The reason in my mind with doing it. Heavy demand domestic usage generally happens twice a day. In the morning and in the evening. Total usage give or take 1hr or so. So the other 23 hrs of the day your running an oversized boiler and we are talking heating season never mind April through September. That's alot of boiler firing up to make a domestic load.

add

when cleaning a utica boiler

yes i agree with ice, i also  come across a lot of them where no one ever boders to take off the top a clean it properly....

billtwocase

I kinda agree

but they are most likely home all day being elderly, so there may be more than just a morning and evening demand for hat water. No matter how you slice it, the boiler is twice the size it needs to be. Sad part is that the son installed it. Good deal on a 4 section with a coil. I would also say they need to insulate. The home was renovated in the 60's using the insulation that was required at that time. Needless to say it was like newspaper back then, so whatever heat is being generated, it is going thru the walls and ceilings. Energy audit would be a plus here

NTL1991

Thanks

Thanks for all the replies!



My brother cleans the boiler just about every heating season. He's a master pipe fitter and installs boilers for a living. (He did not select or install this boiler; my brother-in-law did...) If my parents were perfect strangers, he'd be right there to help them out, but for family members with heating problems, it seems like we end up on the back burner... (ESPECIALLY during the winter months, when he's most busy)



Because a new, smaller boiler is *definitely* not in the cards for my parents right now, I'll have to do the best I can getting this huge boiler more efficient.



The system has one circulator, on the return, and the four zone valves are just above the circulator. The Boilermate is piped exactly as the three other heating zones are piped; so I don't think it's on a priority zone.



I will start by lowering the HI limit. By taking the total BTU heat loss for each zone, and dividing it by the linear footage of baseboard in that zone, then I will get the required BTU per foot. By looking at the baseboard manufacturers spec sheet (I believe they have Slant-Fin throughout the house) and the temperature/btu chart, I can come up with the proper temperature of the boiler.By using the highest temperature required of the 3 zones, I can probably set the HI limit back significantly. I can also drop the low limit a bit, and perhaps, increase the differential some.



I will also need to remove the sheet metal screw which the damper is hanging up on. The draft regulator probably needs to be adjusted, and the stack temperature and CO2 levels both need to be lower.



I used Taco's FloPro software to calculate the heat loss. To make sure I was correct, I did it again, manually, using the R-values of all the building materials, etc. and came up with 57,000 BTU/hr heat loss, compared to FloPro's 52,000 BTU/hr, which in my opinion is quite close for an automatic calculation.



If anyone can think of anything else, I'd be more than happy to try it out...



Thanks Again

Bob Gagnon plumbing and heating

Utica

Clean the boiler, a little soot can really cuts down on efficiency. I recently looked at a boiler I put in ten years ago, the homeowner never had it cleaned and it was full of soot, still the oil usage doesn't seem that high for this area. Check with the oil company for usage history going back to the old boiler. Think about installing a mini zone in the living room and/or bathroom. You can save a lot of energy by putting heat right where you need it.Call MassSave 1-866-527-7283, if national grid is your electric co. They offer 75% off on insulation and weather sealing.



Thanks, Bob Gagnon

chapchap70

Unfortunately, I work on a lot of these

I see a lot of these boilers because our company installs them.  We usually install Riello's in these.  Since you have a Beckett AFG, you can fire it at 1 gph with a .8580B (Delavan) at 140 PSI with a F3 end cone.  The settings I gave you are for the 4100.  The 4150 should have a F6 end cone.  The first digit is the number of boiler sections.  So for the four section, the three model numbers are the 4100, 4125, and 4150 with the difference being the firing rates.  See attached manual.



The -02,-03 draft settings are about right because the boiler pins/passages are wide open so there is little restriction of the flue gases.  This leads to higher flue gas temps.  I usually get between 450 and 500 net stack temps after vacuuming.  The CO2 shouldn't be much above 12.  With the screw taken out of the draft regulator door, the draft may increase to -03,-04.

Robert O'Brien

Brad

I'm dying to know the formula you use back out the heat loss from consumption!