whistlenut wrote:Remember guys, you might have a boiler online anyway, or if it is a brand new installation, why not consider the base LL boiler and have a separate oil or gas boiler?! You could buy an oil or gas boiler new or used for short money and not even have to think about the changeover of fuel types in an emergency. I know everyone wants this to all be in a sweet gift wrapped little package, but that has a price, one that would be far greater than a separate boiler. In the highly unlikely event that a coal unit would fail, having a plan 'B' is admirable, but understand that I have 3 260's running for over 35 years without any oil or gas backup (another coal boiler sits as a reserve) and people live in apts that require heat and hot water 24/7/365.
whistlenut, I know this topic has been beaten to death over the years. The biggest concern/issue is the lack of efficiency in one of the fuels in a dual fuel. Usually it's the oil. Since the oil is the backup or just for summer hot water, I would argue that the lack of efficiency in oil is not a huge concern. Coal would be the primary heat source & the unit was designed for coal.
I agree that having a backup boiler is nice (we are all engineers at heart and we love multiple redundancies), but as you stated the reality is that the probability of having to use the backup boiler oil boiler when you have a duel fuel boiler is highly unlikely.
What intrigued me about this design was the fact that this was an Axeman boiler originally designed for oil. And if it has Pete Axeman's & Matt's blessing on coal, I would think that it is pretty efficient on both the coal & oil side.
whistlenut wrote:One other thought, in wiring your controls, we ALWAYS bypass the circulator functions of a 8124 or whatever, and wire the pumps or zone valves to open or start on demand through a Taco controller, regardless or the temp of the boiler. If you lose fire for any reason, you still have circulation, and moving water will not freeze. This is not new, we have done it this way for 40 years. I know it gets just as cold where you live, and copper snaps in a heartbeat if it freezes there also.....just saves the 'emergency nature' of an outfire when it's 10 degrees out.
I never heard that mentioned before, but it is a great idea!!! I'm going to do that in my house & in my tenants apartments. I spent one Sat with my mechanical guy thawing out their entire apartment this winter, fixing breaks b/c they ran out of oil.
whistlenut wrote:There are other ways to make your dollar go further, and yes, Dave and Matt can engineer an auto changeover system for fuels, but it is not necessary IMO. It could double the price, and I see no reason for adding the complexity. KISS philosophy works every time. This is not rocket scienc
I agree that double the price would not be worth it. I would stick to the manual switchover on oil. But if they could do it for an additional $700. That's worth every penny in my opinion.