Water Heater Question

[joshuaviktor]

Ok, a bit of a weird question. I have an oil burner with an indirect coil to heat my hot water. Sort of an endless heater system.

I intend to do quite a few things to my house, which I have been discussing extensively here, and picking lots of brain bits as well (thanks!).

However, if I manage to seriously reduce the amount of oil I burn to heat the house, I would be reducing the amount of time the burner runs, thereby cutting my hot water supply short. If it runs to heat water, I'm negating my savings, yes? Even if it doesn't run to heat the house?

I did see a heat storage system from Tarm, which claims to let you run the sucker once, and have hot water for days, without running it again.

It seems like a camp hot water heater for showers I once built for Pennsic. It was a copper coil in a tub, over a fire. This is the copper coil in an insulated tub, warmed by a fire, then stored.

Anyone's Ideas? And any idea on price and quality?

Thanks,

Joshua

 

[Mike Wilson]

A boiler fired hot water system is more efficient than a separate hot water heater, however you must have a storage tank to get your efficiency. Most oil burners run at 1.25-1.5 gal/hr, and you don't want it cycling too often. Several manufacturers make storage tanks, and they are very, very well insulated. A few short firings a day from the boiler and you are set. I have one here, however the boiler is secondary to my solar hot water panels. The tank is about 4' high and 3' wide in total, and is surrounded with hard insulation. I have a separate insulation blanket over that. Boiler is a Buderus, with a Riello burner.

 

[begreen]

However, if I manage to seriously reduce the amount of oil I burn to heat the house, I would be reducing the amount of time the burner runs, thereby cutting my hot water supply short. If it runs to heat water, I'm negating my savings, yes? Even if it doesn't run to heat the house?

The domestic hotwater response of the boiler is triggered by a separate aquastat. This is how one gets hot water in the summer. If the boiler is a newer modern and efficient design, then the oil consumption shouldn't be too bad for dom. HW. You could add a small insulated tank on the output as a buffer if desired. The big tanks shown on the Tarm website are to buffer the times between wood firings for hot water heating systems. They would be overkill for domestic hotwater.

PS: Mike, how do you like the Buderus?

 

[zogboy]

I have a burdreris with a tank that is stainlell steel inside carbon steel water jacket it demands its on heat but is very effiecent compared to electric.
We seem to have an endless supply but now pay 2.50 a gal for oil.
For electric to be cheaper oil would need to cost over $15 a gal
John

 

[elkimmeg]

Depends upon your burner its age and how much sediment has collected in your hot water heating coil
Many builder's specials are steel boilers with a life expectancy of 10+ years Next step up is a cast iron boiler life expectancy 30 to 50 years including some major repairs on the way ( changing the hot water heating coil the mixing vavle, circulators, Zone valves, ect)
Most burners have either Becket burners or Carlins Right now I think the Carlins are better,Next step up the foreign Euorpean boilers like Viseman and Buderus Lot of feaures higher effeciencies great boilers if one can afford the extra grand.

What the oil companies and manufactures don't tell the consumers is that high effeciency is short lived. Once the carbon resides on the boiler firing head and flue effeciency drops. Even the yearly tune up and cleanout, never gets it back to the day it first fired. An example, common effeciencies of cast iron boilers peak at between 80 to 84.5%, A lot better than 20 years ago at 68%. The next year testing is 76 to 80%. Same proportional results for the Viseman and Buderus, Some can be setup to obtain up to 86.5% realistically only a few percentage points above a good Weld McClain, add the Carlin burner head and the difference can be reduced to 1%. Like the BTU ratings and lenght of burns the yellow EPA sticker claims up to 88%+. I have never inspected one single oil burner attaing optium effeciency. One factor explaining this, is the oil purity or lack of it. Your tank filter does only so much to remove impurities. This also explains part of the carbonization I mentioned earlier. If we could get a better quality of oil it would burn better. I am reporting real world conditions gathered for hundreds of inspections. I check the effeciency ratings and actual field test results. A new Viseman
should not test out at 81.5%, I witnessed two weeks back. What was found, was the wrong flow rate head and also the wrong angle. Once the replaced with the correct injector it tested 84.5 Some older boilers effeciency can be increased by changing the injector heads using different flow, spray, or angle. The electrode gap can also be tweaked to squeeze a little more out.

Back to the main Question, Tankless hot water: Lots of variations, one setup an aqua bost system run off a zone valve. ( usually added for extra capacity if the thankess cannot keep up with the demand). Today newer boilers have increased the effeciency and vollume delivering Hot water. Instead of the 2 to 3 gal per minute some can deliver 4.5. Actually in winter if the boiler cycles for heat the fire box is already warm and producing hot water is cheap . Another option increasing in popularity, is oil fired hot water tanks. All the advantages of gas rapid recovery storage tank uses only the oil for hot water, The burner does not have to cycle in summer. So much cheaper to produce hot water than the electric models but Electric still is an option. Like Gas heaters, the oil fired hot water heater can be tied into the existing burner flue. No separate flue is required. Down side of oil hot water heaters are much more expensive than electric or gas hot water tanks. but usually of higher quality construction and lasting many years longer.

 

[babalu87]

You guys are essentially talking about a boilermate right?

(broken link removed to http://www.amtrol.com/pdf/classic.pdf)

I know I can build something that will work, now I just have to finish everything else I have going on

Havent burned a drop of oil for heat this season though

 

[joshuaviktor]

Yes, I have the amtrol boilermate. Should I insulate it?

 

[babalu87]

It can only help
I know they are insulated but more = better

 

[Mike Wilson]

Per hour, Dylan, per hour.

BeGreen: I love the Buderus. It was the most efficient boiler I could find, and matched with the Riello burner, which is a triple pass burner, I've noticed significant savings over my former Weil-McLain and Beckett combination. Its plumbed into a 3 zone oil fired hydronic hot air system. As for Elk's argument that they aren't as efficient once you use them, its probably true. I also think that a new Weil McLain loses efficiency once I turn it on, as does any burner. So, if one starts at 87% efficiency and the other starts at 78% efficiency, they probably both lose a few percent as they age. I'm glad I am starting from a higher efficiency.

-- Mike

 

[fbelec]

josh the boiler mate is only suppose to lose 1 degree every 24 hours. insulating it would be more of a pain than it is worth. i help install the buderus boilers. they are right now the most eff. oil burner at 87 %. a install we did 3 years ago that has been cleaned and tuned every year is checked with a bacarac tester. this is a test for temp, carbon manox, eff. at three years old the eff last month was 86.5 %. not bad for three years old. this person has a very big house. it had one weil mclean boiler with two boilermates. she was using 1 tank of oil every week. we put in two g215 buderus boilers to the two boilermates and a tekmar computer controller with outside temp sensor. she now burns 1 tank of oil every three weeks. back to the buderus, great boiler. just a little loud. even with the riello burner.

btw a company here in mass makes a wall hung boiler that is 99% eff. the company name is heat transfer products. the same company that makes superstore tanks and another great boiler called the munchkin. a friend of mine has this 99%eff boiler and so far over the same time last year it's dropped 1/3 0ff the usage of gas.

just a little info if anybody cares