The wife and I purchased an old "victorian" farmhouse about six years ago and have been slowly bringing it back to life.. lime mortar, shellac, K&T wiring,vapor barriers... what I didn't know six years ago! Greatly appreciate the knowledge and experience on this forum and looking for help/input on heating options for next summers upgrade.
- The House: 1860ish two story brick house with 2 and 3 brick thick exterior walls. ~ 1450 sq ft on the first floor (10 ft ceilings) is heated with hot water. 2nd floor is forced air
- Current boiler: 1978 252,000 BTU Adlrich L 25 W . At some point in the past, the oil burner in the orginal boiler was replaced with an Adams Speedflame natgas burner . Boiler has no protection/plumbing in place to prevent sub 130-140F from entering the heat exchanger. It routinely gets fed 60F water (how has it survived this long!?!)
- Plumbing: "U" shaped two zone. Supply starts with 2 1/2" black pipe for each zone, steps down at each radiator, 3/4" pipe at far end of each zone. Return water is piped the same (3/4-2 1/2"). Both return water pipes are combined, enter the 1/12 hp B&G series 100 pump, and the water is forced in the bottom of the boiler, heated and spilt into the two supply runs shortly after exiting the boiler. Typical delta T for ret/sup is ~15F
-Radiators: cast iron Weil McClain Cameo's. Typical winter day they do not exceed 120-125F...on the coldest winter days over the past 6 years, the have not needed to be above 140-145F to keep the house comfortable.
-Additional heat sources: Woodstock Progress hybrid wood stove (30-70,000 btu) and Mitsubishi 2ton mini split (MUZ/MSZ GE24NA) (~24,000 btu of heat)
- Slant fin Calc: with a -20F (worst case temp) is 191,9xx btu/hr
For all but the coldest 30-45 days of year, the woodstove and Mitsubishi heat pump will provide adequate heat for the house. However, for the very coldest 2-10 days of the year they will provide no heat, and the boiler will need to supply 100%
The current boiler/burner is not very efficient and I am not sure how long it will continue to function with the very cold return water. Moreover, as I have tighten up the air leaks in the attic, basement, crawlspace, etc. the pilot light/ burner will not ignite unless I open an exterior basement door...backdrafts. (no draft hood on the boiler, etc, etc....not very wife friendly)
I have two thoughts on how to address my upcoming boiler/heating issues:
1) Replace existing boiler with a ~85% cast iron power venting (low ceilings in the basement) or go with a more efficient mod/con boiler in the same physical location in the basement.
2) The dicey option...Leave the existing boiler in place, turned "off", and add a dedicated tankless hot water heater: 20 feet away from boiler on the west zone, I have two "abandoned" 1" ports on the 2 1/2" ret/sup pipe. What if the supply from the "cold" boiler is piped to the cold inlet of the tankless hot water heater, and 130F water is returned to the boiler to mixed and distributed through the system. I suspect the current B&G series 100 pump with 4' column of water above it and 20' away would deliver 8ish gpm to the hot water heater? Something like the Rheem RTGH-95DVLN might be a good fit? (if the water heater failed, etc. the main boiler could be put into service quickly)
Dana, I have read a few of your older posts regarding the efficiency/ benefits of low mass "boilers" combined with high mass/low temperature water returns. The second option I tried to outline above is my attempt (feeble?)to use the 26 gal of water in the existing boiler, piping, radiators, etc. to my benefit.
Would greatly appreciate any/all input.....even if it is negative!
Thanks,
Tim
- The House: 1860ish two story brick house with 2 and 3 brick thick exterior walls. ~ 1450 sq ft on the first floor (10 ft ceilings) is heated with hot water. 2nd floor is forced air
- Current boiler: 1978 252,000 BTU Adlrich L 25 W . At some point in the past, the oil burner in the orginal boiler was replaced with an Adams Speedflame natgas burner . Boiler has no protection/plumbing in place to prevent sub 130-140F from entering the heat exchanger. It routinely gets fed 60F water (how has it survived this long!?!)
- Plumbing: "U" shaped two zone. Supply starts with 2 1/2" black pipe for each zone, steps down at each radiator, 3/4" pipe at far end of each zone. Return water is piped the same (3/4-2 1/2"). Both return water pipes are combined, enter the 1/12 hp B&G series 100 pump, and the water is forced in the bottom of the boiler, heated and spilt into the two supply runs shortly after exiting the boiler. Typical delta T for ret/sup is ~15F
-Radiators: cast iron Weil McClain Cameo's. Typical winter day they do not exceed 120-125F...on the coldest winter days over the past 6 years, the have not needed to be above 140-145F to keep the house comfortable.
-Additional heat sources: Woodstock Progress hybrid wood stove (30-70,000 btu) and Mitsubishi 2ton mini split (MUZ/MSZ GE24NA) (~24,000 btu of heat)
- Slant fin Calc: with a -20F (worst case temp) is 191,9xx btu/hr
For all but the coldest 30-45 days of year, the woodstove and Mitsubishi heat pump will provide adequate heat for the house. However, for the very coldest 2-10 days of the year they will provide no heat, and the boiler will need to supply 100%
The current boiler/burner is not very efficient and I am not sure how long it will continue to function with the very cold return water. Moreover, as I have tighten up the air leaks in the attic, basement, crawlspace, etc. the pilot light/ burner will not ignite unless I open an exterior basement door...backdrafts. (no draft hood on the boiler, etc, etc....not very wife friendly)
I have two thoughts on how to address my upcoming boiler/heating issues:
1) Replace existing boiler with a ~85% cast iron power venting (low ceilings in the basement) or go with a more efficient mod/con boiler in the same physical location in the basement.
2) The dicey option...Leave the existing boiler in place, turned "off", and add a dedicated tankless hot water heater: 20 feet away from boiler on the west zone, I have two "abandoned" 1" ports on the 2 1/2" ret/sup pipe. What if the supply from the "cold" boiler is piped to the cold inlet of the tankless hot water heater, and 130F water is returned to the boiler to mixed and distributed through the system. I suspect the current B&G series 100 pump with 4' column of water above it and 20' away would deliver 8ish gpm to the hot water heater? Something like the Rheem RTGH-95DVLN might be a good fit? (if the water heater failed, etc. the main boiler could be put into service quickly)
Dana, I have read a few of your older posts regarding the efficiency/ benefits of low mass "boilers" combined with high mass/low temperature water returns. The second option I tried to outline above is my attempt (feeble?)to use the 26 gal of water in the existing boiler, piping, radiators, etc. to my benefit.
Would greatly appreciate any/all input.....even if it is negative!
Thanks,
Tim