I just joined this forum today, but I have been reading it over the past month or two. It is a fantastic resource! Thanks to all who have posted, I have learned a lot. I have been heating with an oil boiler and a radiant coal stove. The oil boiler is 37 yrs old, and I am no longer willing to pay the high price for oil. So I have been looking at coal boilers (stokers in particular). I like the AHS-130, but not the price, bumping, or documentation!
I have read on this forum that the manual is not very good. I also read that they were improving it (year old thread). I didn’t see any manual on their website. I am concerned with a unique boiler, and the lack of good documentation, how I will service it (or get it serviced). I would like to have a good set of drawings, parts list, and schematics. If these last 30+ years, something is going to need fixed in that time! If I go with the AHS-130, I would like to consider some of the modifications that Yanche has suggested.
Specify more tapings
Is the AHS-130 controlled with an aquastat? Doesn’t that sense the boiler temp? I don’t understand why I would need to sense boiler temp in more than one place. If you don’t specify the DHW coil, but want to add one later, then I would need the large tapped hole for the coil, and a plug for it since it is not installed… is that correct?
Variable Speed fan motor
I like the idea, and would like to at the same time come up with a way to thermally isolate it from the boiler. Maybe a non-thermally conductive shaft coupling? Any ideas as to what parameters you would use to control the speed? Doesn’t the boiler as it is delivered from the factory, have only two states, full on, and idle? Would the variable speed fan provide a variable burn rate, and are you trying to keep the boiler at a constant burn rate? But… doesn’t this fan aid in creating a turbulent airflow inside the boiler, so the heat transfer in to the water is better?
I definitely would add an outdoor temp reset control. Is there a particular controller you would recommend?
Shaker / ash removal thermal sensor control
As I understand it, there is a thermal sensor in the as path, and based on the temperature of the ashes, the shaker turns on and off. Is there any more sophistication required? What controller would you suggest if not the Fuji?
This is starting to sound like a good microcontroller application. One controller for the fan motor, ash temp control, and outdoor temp reset. Inputs would be boiler temp, ash temp, outside temp, zone thermostats, outputs would be for the fan motor speed, and ash shaker control. You could also work in a DHW priority for an indirect DHW tank, and maybe even control the DHW zone to dump heat into when the call for heat is satisfied. It would be some work for sure, but ought to increase the efficiency for the lifetime of the boiler.
Any thoughts, or interest?