I have a 4,000 sq ft Victorian home that built around 1900. I purchased it 2 years ago. It came with aluminum siding and a new roof with a ridge vent. I soon learned that it had no insulation in the attic or walls so contracted blow-in insulation and soffit and proper vents to make the ridge vent function properly. We also replaced 11 of the 43 windows and tightened up most of the drafts. However, my oil bill is still about $3,000 per heating season. I was going to update the hydronic hot water generator after last season but the oil company stuck me with a full tank in April. So here I am spending another 3K on oil.
My dilemma is this, the hot water system consists of a 4 inch supply header (around 60 feet long) with individual feeds to each radiator that go back through another 4 inch return header. I’m sure this is great for getting the same temperature water to all of the radiators but I’m concerned that the modern generators aren’t suited to Header type systems. I have a summer cottage at the shore that has a modern Weil McClain generator and noticed that there is no such header. It works great making all of the radiators quite hot and heats the house very quickly. If I go to a modern High Efficiency gas system, will I have to change the whole piping arrangement ?
I should also point out that I invested about $600 on piping insulation and insulated both supply and return headers as well as the accessible portions of the branches to the radiators in the basement and crawl spaces. I figure most of the energy I’m wasting is heating up this large volume of water in both the generator (probably built in the 40′s -General motors, Delco heat) and headers.
Thanks for your help.
Sounds like you have a real problem.
You first need to decide if you want to stick with oil or switch to gas. I assume your existing oil boiler is very old and past time to replace. Many boilers designed for gas firing can be converted to oil or even use both, but if it is over 20 years old it is time to replace. Your piping headers and piping distribution layout is a function of the heating system design, not the boiler.
You did not say if your system has a pump, but most systems using large headers in residential systems are designed to operate without any pumping, so most likely this is a very old system which did not use pumps. If the radiators are OK, I would scrap the boiler, headers, and replace with new high efficiency boiler, zone valves, and circulating pump. With a pump your piping will be in the 1″ TO 1-1/2″ size range at the boiler, and most likely 1/2 to 3/4″ run-outs from the mains to the radiation. With a pump system, you can have several zone valves and wall thermostats to allow having different temperatures in different rooms to save energy. Finally, decide if oil or gas in your area will be your best long term best choice and go with that fuel type boiler.
Thanks for your input. Here are some more specifics about my system that should clarify things:
Yes, there is a large circulator pump on the return side of the boiler. It apparently forces hot water out and into the main supply header. The supply header runs the length of the house 4 inch most of the way and then 3 inch for the last 15 feet. Then 1 ” and 1 1/2″ branches go to each individual radiator. I have to say, this seems like a good system to evenly distribute the hot water to all of the radiators. And I have to ask, without a header, how is this accomplished ? Do modern systems run like a daisy chain, with each successive radiator downstream from the next ? Doesn’t that make the radiators early in the chain too hot and those at the end too cold ? What I was hoping to hear from you is to be able to just replace my boiler with a new Modern (I have gas service in my house now) gas high efficiency boiler and still use the header system for distribution. Especially since the piping is now freshly insulated. I also can’t replace the run-outs to the radiators with smaller piping because those pipes are mostly buried in the walls. Thanks again for your help.
I was trying to say that most of today’s systems do not require large header piping which saves pipe and insulation costs. For most residential hydronic heating systems, a 1-1/2 to 2″ main piping header is more than large enough to handle any water flow a typical residential circulating pump can handle. You will never see a 4″ main header pipe today unless the facility is a school or large office with much larger boilers and circulating pumps.
I still bet this system was originally designed to operate by gravity flow (heat rises, cold falls) without a pump. Many of these older systems worked this way by using over-sized piping. If this piping is in good condition, the only real problem is the higher heat losses due to the larger pipe surface area and related higher pipe insulation costs. If this piping is in good condition, you can use almost any size pump and boiler without any heat distribution problem. However, if it is old, you better hope you never have a leak as this old piping is almost impossible to repair due to thinning pipe walls or corrosion. Once you try to un-screw a fitting something else will break or leak and it never ends.