A person named Nahsani recently posted the following on the alt.hvac
newsgroup:

"My two-year old Slantfin Boiler won't heat the house above 65 degrees, and
it's usually at 60 degrees. It'll come on and off randomly for short
periods of time (as short as one second) and over a long period of time,
it may bring up the temp to 65. As another example, I had the (new)
thermostat, which my oil company replaced saying that was the problem, up
to 72 overnight and into the day, and the temp in the house is still 60
degrees. I have also left the thermostat pegged on high for two days with
the same result. The company who installed the boiler doesn't, for some
reason, believe that this problem exists, because when they came, the
house was "warm" i.e. 65 degrees! and the gauges on the boiler were up to
the correct pressure. I have obviously severed business relations with
them, but I still have the problem. Any ideas what might be causing this?"

And, he later wrote:

"My old boiler was ancient - 50 year old, big. Then it puffed back and
wrecked my house. Anyway, I only replaced the boiler and the pipes leading
into it. It used to work fine (the new one). Although my ex-boiler guy
insisted that the on and off operation is normal, I really think it's
important. I would say the btu rating is less for the new boiler, but I
don't know and I don't know what the old one was. I've lived here for 13
years and it is a tiny house - 810 sq.ft. one floor. Mostly new windows
and insulation. The whole house is cold and I have no idea about the
piping. The weird thing is that it got my house up to 70 yesterday, for
the first time in a long while. Today, it won't get going."

I decided to also post it here in case anyone here has and ideas or
suggestions.