HELP!! Cast Iron Baseboard problems!!

[KeepItNatural]

Hi All,
My father and I are having a problem with our heat. In his bedroom, the radiator is hot to the touch but it does not seem to be getting the heat out into the room. It is not triggering the thermostat causing the heater to run nearly constantly.
We are at a loss of what to do. Do we need to "bleed" the system? Does something inside the pipes in the baseboard sound like it isn't working?
My father checked all the pipes and said they were hot to the touch so that told us none of the pipes were frozen, since the room has three exterior walls.

The radiator is cast iron baseboard.

This is the first time we've had this problem. We have been in this house for 3 years. It seems strange that this would be happening all of a sudden.
Any and all help would be greatly appreciated. Full discloser- this is run off of an oil furnace, but I didn't know who else to ask.
Thanks guys.

 

[velvetfoot]

I'm no expert, but has it been really cold there?
Maybe the system is at capacity.

 

[peakbagger]

Here are some general things to check.

Are you running a setback thermostat? If the radiation was sized marginally, there may not be enough surface area to supply the extra heat required to bring the room back up to temp from the setback temp during cold weather. I take it that someone hasnt installed any new floor length drapes over the radiators? If they truly are baseboard type cast iron radiators, is there a chance that the room was carpeted or new flooring installed? I have seen several installations where the new flooring was installed in the return air slot on the bottom of the radiator, effectively reducing the amount of convection air passes the coils. The proper thing to do is to raise the radiator ,but most flooring companies dont.

You could have a marginal circulator pump on that zone. If you can get a good thermistor, thermocouple, or IR thermometer you could take the surface temps of the incoming and outgoing water and compare it to the inlet and outlet of the boiler. If you see more than a 40 degree temp drop across the radiators from begining to end you may not have enough flow. That could be a circulator or a partially air bound radiator. Normally a partially air bound raditor will be noisy with a lot of gurgling but cast iton may dampen the noise. If you access to the clamp on ampmeter, you could check the load on the circ pump, if its not drawing enough current, it means the pump is worn out.