coaledsweat wrote: IIRC, that was why he decided he had to have an Axeman.
jim d wrote:w/ steam you should only fire the load , radaition fan coils ect., then add 15 to 20 % for piping & pick up, thats it nuff said andif you can afford it i would go w/ the efm
Pacowy wrote:I don't really follow how having an idle fire the size of a basketball is an advantage - it seems like you'd be burning a lot of fuel even when you have no call for heat. I've run steam systems in 2 houses with EFM's and have 0 complaints. Other boilers and stoker designs might work equally well, but unless they have real advantages I don't know about, I don't want to trade.
coaledsweat wrote:Axemans don't burn at idle, they basically choke off the fire.
jim d wrote:mike why would youhave a boiler that isn't performing properly , fix it , it's more likely that the boiler mfgrs overrate their boilers ,that fomular for sizing steam boilers has served me well for 50 years
Pacowy wrote:jim d wrote:mike why would youhave a boiler that isn't performing properly , fix it , it's more likely that the boiler mfgrs overrate their boilers ,that fomular for sizing steam boilers has served me well for 50 years
I think we're at least partly agreeing here. I see people measuring their installed radiation, adding a small pick-up factor and then deciding what boiler to buy based on the ratings on the manufacturer websites. I agree with you that many of those ratings are higher than the unit is actually likely to perform, and that's part of why I'd be more comfortable with specifying more excess capacity. I've seen all kind of weird stuff happen when stokers of different designs get pushed close to their maximum output. For example, I had a flat plate stoker that picked a deep cold spell to let me know my recent coal delivery was more prone to clinker formation - due to plowing, etc., I had to baby it when I needed it to really go. Likewise, even EFM's can come up short at the top end if your coal has too large of a % of undersized pieces, but you may not find that out until you need that output. Making steam by coal, I'm much more comfortable building in excess capacity to provide protection against such factors, not to mention the boiler needs cleaning/DHW needs/future expansion/etc. factors that might lead you want to keep some capacity in reserve. And I know I'm repeating myself, but I believe I'd get the same heat with less coal using a bigger boiler running at 2/3 of its capacity vs. a smaller boiler running flat out (at least if the bigger boiler has a bigger heat exchanger). If someone has more info on that theory I'd be happy to hear it.
P.S. The older EFM literature I've seen seems to call for pickup factors of 1.33-1.35.
Pacowy wrote:coaledsweat wrote:Axemans don't burn at idle, they basically choke off the fire.
This was bugging me at breakfast this morning. I think the earlier posts said the Axemans tend to maintain a high boiler water temp because the idle fire is the size of a basketball. If it's giving off enough heat to maintain high boiler water temps (relative to a stoker with a smaller idle fire), it seems like it has to be taking in air and burning fuel to do so?