High efficiency oil boiler.

Mike4484

I am looking into buying a new oil boiler for my 150yo 2500sf house. There is minimal insulation but the windows and doors are newer. I have installed new ecostyle radiators throughout. I was figuring on 90k btu, what would you recommend? What is the highest efficiency I can get in an oil boiler? There is no natural gas service in the area and I don't want a propane tank in my yard.

Thanks

pecmsg

you need a heat load/loss calculation. aka Manual “J”

EBEBRATT-Ed

Do a heat loss to get the sizing right. All the oil boiler have about the same efficiency. Mid 80s efficiency

Mike4484

How do I do a heat loss calculation if I don't currently have a working heating/cooling system? I am renovating a 150yo house and nearing the end of the project. Currently there is a 40yo HS Tarm multi fuel boiler but it is not hooked up because the house had been foreclosed and wasn't winterized. All of the existing pipes had burst on the second floor so I ran new pex throughout

Steamhead

You need a proper calc program. Slant/Fin had a very simple one called Hydronic Explorer, but unfortunately that company is out of business. You might be able to find it online for download, however.

EBEBRATT-Ed

A heat loss calculation is based on the buildings insulation (type and thickness) windows & doors (single paine, double paine size and efficiency and area of walls, floors and ceilings. And the design conditions of the location the house is located in. 70 deg indoor temp and 0 deg outdoor temp??

It has nothing to do with any existing system which may or may not be the correct size.

KC_Jones

How did you properly size the brand new radiation if you didn’t do the room by room heatloss calculations? Those calculations should have been done already and then the boiler size would be known from that.

Mike4484

I just added together the btu's of all of the radiators combined and rounded up. I used the calculator on the manufacturer's site for the radiators when I purchased them. Wasn't sure if that would accout for system heat loss since it didn't ask about the size of the boiler or number of radiators being supplied.

leonz

Concentrate on getting the HS TARM boiler ready for the coming winter first. You need to have the existing oil burner serviced or replaced and oil tank checked and cleaned as the oil is bad after all this time and it needs to be pumped out.

The chimney needs to be cleaned and a cap or chimney extension installed if it does not have a cap already and the flue pipes most likely need to be replaced. Your HS Tarm boiler has a massive amount of water to create thermal mass and heat your home.

The oil side of the firebox has a massive amount of water over it and a domestic hot water coil as well. The oil burner fire box is wide open and the oil fire also passes 3 sets of baffles filled with water and a wet base as well so you have plenty of water to use. You can always add a 490 gallon fully insulated rectangular hot water storage tank from New Horizons to increase the amount of useable thermal mass as well.

The OT 28S has 73.5 gallons of water in it, the OT35S has 76 gallons of water in it, the OT50S has 91 gallons of water in it, The OT70S has 130 gallons of water in it.

HSTARM OT-Series-Manual.pdf

HSTARM OT-Brochure.pdf