My water to air exchanger is at 175 degrees with the furnace blower off, but when the stat calls for heat and the blower comes on, the return side of the exchanger drops to about 125 degrees or less and the blower runs for hours trying to satisfy the t-stat. does anyone know what my problem is? Thanks in advance for the help.
you should be aiming for 8 to 10 gpm going through your exchanger. this would likley keep your return line at about 7 to 10 degrees cooler than the feed line.
like others have said, make sure you have no air lock in the rad (this could prevent your rad from filling all the way and cause your problem)
do you have a zone valve controlling the flow of water to yoru rad? if so, it may not be openingn all the way
how big of line is going to your rad can determine the flow of water also
how far you OWB is from teh house, the number of elbows and fittings and the size of your underground lines can all have an impact on how well your pump works, and the size of your pump needs to be matched to the piping system as well
your problem has many possable answers, air lock, bad control valve restricting flow,too low gpm being delivered by the pump
check the easiest things first, i would make sure there is no air lock. then if there were a valve controlling the flow of water to the rad i would bypas that to see if it helped, then i would check the flow rate at the return line of the OWB