OK, kind of a complicated question here...

I have an old installation 14x14 bedroom, 1/2 in pex under sub-floor, conduction plates, on 16" centers. Yes it does not provide adequate Btu's because I was poorly advised about 10 years ago. Should have been on 8" centers. That being said, plus the fact that I can not fix it this season, I was wondering if I could help maximize the heat transfer with pump speed. I have a Grudfos UPS 15-42F pump with approx speeds of 1900, 2200, and 2500 RPM. I also do not have a delta t number because I don't have a thermometer. If I do get a thermometer, would I adjust the speed for an optimal delta t? Is there a general philosophy on pump speed?

Please advise, thanks in advance!!

The heat load analysis determines all radiant floor design parameters.

Minimum water flow is critical to the output of any radiant panel, but the least of the several factors that matter.

First is the heat transfer area, followed by water temperature.

Single tube installations (with or without plates) are unfortunately very common and often promoted by those who would take advantage of the naive, trying to fit radiant floors into the budget or find a "better" deal.

They are a black eye for the industry and should be lumped in with the sub-standard "open" systems.

A couple of ideas: How about adding radiators to the circuit to get more heat into the room. How about adding a radiant panel to a wall? Drywall's not too difficult. Could you add such a panel to your circuit - or add a new circuit?

as morgan says, pumps speed is the smallest factor on output. that said, you might as well turn it up, it'll help, but maybe not enough to make you happy.

I just ordered a non contact thermometer, I'll post the temps when I can. I believe I also have the heat loss numbers somewhere. It seems to me that if I have the water temp and heat loss numbers, along with the dimensions of the room and tube size, I'll be able to(with the help from you posters) determine how far off this system is from a properly designed system. Anything else needed that I am missing?

Oh yes I did max the pump speed out. If I can get 1 0r 2 degree heat rise, I'll take it at this point. Like I mentioned in the original post, I can not address the issue properly this year unfortunately. I will wind up taking down the ceiling, and will re-do the pex on 8" centers next year.