steam boiler and tankless coil

bh

I had a new steam boiler installed a year ago (peerless) with a tankless coil for domestic hot water. I also have a woodstove which I use for heat during the winter. When I use the woodstove I can sometimes go for several days without the boiler kicking on for heat. But because I get my DHW of it and it is in an unheated basement, it cycles quite frequently to maintain temp. THe situation is the same, of course, in the summer when it is making DHW but not heating. So it strikes me as very inefficent-- and this is confirmed by my heating oil bills.

So I am trying to decide what to do. I am considering installing an electric hot water heater (with a .95 energy factor) and piping the cold inlet through the tankeless coil so that in the winter when heating and DHW usage happen to coincide I get the benefit of the preheated water without all the wasted cycling to maintain temp. But I of course understand that electric DHW is quite inefficent. Gas is not an option. So any input on whether this makes sense to do, whether I just better off as is, or whether it would be work the extra 1k or so to get an indirect tank system put in? Remember, though, this is a steam system. My understanding is that because of the relatively larger volume of water in a steam boiler, an indirect system is less efficient than it would be in a hot water heat set-up as more gets wasted on the boiler water itself and then is disipated. thanks very much for any input

Big Ed

Another Option

You can install a aquabooster which uses the coil and a bronze circulator to build a storage of heated water.This way you don't have to deal with the solids in te boiler water.....

With the Peerless I recommend mataining a minimal standby temperature .So I would use a triple aquastat. Which would mantain low temperature,have a higher hot water producing temperature setting and a relay for switching on the pump......

mark schofield

Carlin Aquabank

I recently replaced a 30 year old New Yorker hot water steel boiler with tankless coil with a WM WTGO3 boiler with tankless coil. The origional system had what Big Ed discribes. A packaged system by Carlin which included the circulator and tank (with temp sensor) which is connected to the tankless coil. It works well, although I would be interrested to know if an indirect would be more efficient. I presently feed the tankless coil with preheated hot water from solar, but when the season and sun dictate (december-january) I can turn a few valves and bring the Aquabank online. The boiler stays on year round at 140 low limit. Durring the summer months it ran about 20 minutes /day. Except for the week with no sun.