I have an office building that has hydronic baseboard along the exterior walls. We just installed a high efficiency gas boiler, and have a problem with one of the zones.

The zone calls continuoously, and only gets about 8-degrees F of drop across the loop.  Which is causing the boiler to drop the burner down to 20%, and then go into a lockout mode, because the retrun temp gets too close to the exit feed temp. 

Looking at the baseboard heaters there is only fin installed under windows, which is about 15% of the length of the run.  Which when I do the heat calcs is about half of what is actually needed. 

So, now the question:  Can I get just a wrap around fin to install in the existing baseboard housing, on the 1-inch copper that is already there? 

I think that would make a huge difference in the comfort of the occupants, and allow the boiler to run more efficiently.  We really can’t take down the system do do an upgrade untill spring, and I’d like to solve the problem sooner than that.