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Old house; old boiler

Just bought a house this summer with a Weil-McLain P566HE-W boiler; supposedly it's 32 years old. It appears to have a Weil-McClain WM-HS-66 oil burner on it (set to settings from manual). In addition, there's some sort of Honeywell box attached to the radiator as well that has a dial that you can set anywhere from 180 degrees to 240 degrees. I'm not sure what this Honeywell box is, but the dial was set at 200 degrees. Am I assuming correctly that this is the water temperature of the system? I turned it down to 180 degrees today, but is there any way to turn it down lower than that? We burn about 100 gallons of oil a month and keep the house set at 58 degrees at night/while at work and 66-68 while we're awake at home. It's starting to get ridiculously expensive--is there any way to save some more money by changing the settings differently? The burner has a "gun adjustment", "primary air setting", and "off cycle damper" settings, but they're basically just number settings and I have no idea what changing them will do. I've seen people talking about "low" and "high" settings for boilers in some of the other posts on this site and can't figure out if my old radiator has that capability or something similar. Any advice on how to save some oil this winter?

Also, based on how much we get in our tax return, we're thinking of getting a new boiler that burns gas. The above WM boiler says it has DOE Heating Capacity of 173,000 BTUs/hr and Net IBR Rating for water of 150,400 BTUs/hr. We have a mixture of column, tube, and baseboard radiators throughout the house. Figured out the BTUs for the column & tube radiators and estimated the baseboards at 500 BTUs/ft and came out to 88,000 BTUs. Used the SlantFin Heat Loss Calculator (to the best of my ability) and got 58,000 BTUs needed for the house overall. Seems to me like the boiler we have is way too big. Took a look at the Energy Star list of certified boilers and it seems like gas is the way to go (most efficient oil boiler is only 93% AFUE). But a lot of those boilers are like 200,000 BTUs! Any recommendations for the upgrade? We want to save as much money as possible on heating costs in the future.

<a href="http://www.energystar.gov/productfinder/product/certified-boilers/results">http://www.energystar.gov/productfinder/product/certified-boilers/results</a>


  • SWEI
    SWEI Member Posts: 7,356
    New boiler

    if you have natural gas available is a good bet.  It must be sized according to a heat loss calculation, which also needs to consider the various types and sizes of radiation in each room.  Where are you located?  We might have someone competent nearby.