Dayton water to air heat exchanger

Good morning i have a question for uses i have a dayton water to air heat exchanger instslled in my garage that is 60 feet away from house. The total pipe length is 240 feet return and supply, the 60 feet that is ran from the house to garage is installed in plastic electrical pvc that is not insulated, the total height of the modine is 7 feet, the fan is rated for 750 to 900 cfm and the water is rated for 49000 btus, i installed 3/4 pex oxygen barrier, it has a stat to turn on the pump and efm 350 stoker, the stoker temp on aqua stat is 170 low 190 high, i have a 007 circ on it, i have 140 at the coil supply and 130 at return with only 60 to 70 degrees of air, this modine was taking out of service bc it had two leaking passes that i repaired. It was feed with steam. Seeing what you guys think

I don't know what the math works out to, but it's not very likely you can deliver 49,000 BTU through 120 feet, one way, of 3/4" PEX. On top of that with no insulation, you are going to loose tons of heat to the ground and your return pipe.

Are you asking about this because the garage is not getting warm enough?

-Don

About your water to air heat exchanger; was it fed with wet steam or dry steam?
We have to get that question out of the way first.

Was there a steam rated air vent in the heater? did you remove it and replace with an air bleeder for hot water? Is the wet drain cap tight if the steam trap is still plumbed in?

Since you are losing so much heat you might as well lower the triple aquastat down to 160 high 140 low to save coal if the garage is uninsulated and invest in a small kerosene fired space heater if you do not spend a lot of time out there.

The uninsulated underground run is going to make this setup a coal hog.

Just trying to teach you how to fish to eat everyday...not just giving you a fish to eat for one day...

Okay, 60-70 degree air out of modine, what are the measured water temps in and out of same?
Also, what are measured water temps in and out back at the headers?

I actually think its the modine bc i had a hugh one in its place and i went smaller i think the modine is blocked

The hugh one worked but the fan was to strong so the fan would over come the heat i shoukd install the old modine and put this smaller fan on it i have 140degrees at the supply of modine and 130 degrees at return

The boiler dosent really run hard it just idles along

One more thing i only need like 30000btus for the garage