"Jmagerl" wrote in message
...
The pump runs continuous but the burner cycles on and off (the water gets
to 190). The thermostat may be old (an old honeywell dial type) but seems
to be working correctly.

You can probably go a few more degrees.


If the heater is struggling, it may just not have the capacity of the system
to do the job.
Since it does cycle off, it is able to get the water hot, but you may not
have enough radiator surface area. Or you don' t have enough insulation, or
you have drafts, etc.
Close off the radiators in unused rooms (if you have any) to get more heat
to the used ones.

Since it will be very cold this week, consider some temporary supplemental
heat. It won't take much for a kerosene or propane heater to kick it up
another five degrees.

Did you post if it saw gas or oil? If oil, the burner may need a cleaning.
If the spray nozzle is not right, you don't get the proper heat. If the
heat exchanger is sooted up, you don't get the proper heat