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[Ryan]

Hello everyone.  I am having problems with figuring out if my system is working correctly.  My outdoor wood boiler temp is set to approx 180-185 degrees and the gauge if correct never drops below 170.  My run from wood boiler to house is 160 ft and is 1 inch pex that is approx 4 years old.  Coming into the house the water is hot to where you cannot hold the pipe.  I have a 50 plate heat exchanger.  The pump from wood boiler to house is a B&G PL-36 the runs 24-7.  In the house I have a gas fired boiler with the gas turned off.  I have a wraparound pump that runs 24-7 to keep the gas boiler warm, that pump is a Taco 007-F5.  From there I have two zones, a baseboard hot water on the main level. Main level is 2000 sq ft with 16 baseboard units, each unit is approx 4 ft long. My second zone is my basement zone with radiant in floor 2000 sq ft.  I keep the mixing valve set low about 85 to keep from drawing the hot water supply down and just the keep the water moving all the time.  Both Zones run constantly and my gas boiler sensor reads under that load the water temp moving through the gas boiler is 118-122 degrees.  Under no load the water temp moving through the gas boiler is 150-160 degrees.  My domestic hot water zone is on priority so when i have a call for hot water it will turn the two zone pumps off and run the domestic zone only.  It takes about 45-60 minutes to satisfy my 53 gallon storage tank which is set at 115 degrees.  Under the domestic load gas boiler sensor reads 118-122 degrees.  My main level baseboard zone is pushed with a taco 007-f5 pump, basement in floor with a grundfos 15-58 3 speed, and domestic hot water with a taco 007-f5. Does this all seem right?  I wish i had temp gauges installed but i dont, I tried measuring temp with a heat gun and i am getting readings all over the place.  If the water coming in is 180 degrees, what should be going back? What should the supply and return temps be on the house side of the exchanger? Are my pumps the correct size? I took the heat gun readings on the same material at the 50 plate heat exchanger, the reading are: Wood boiler side supply 180, return 125. House side supply 145, return 120. I also took some reading on my baseboard zone same material supply 140-145 return 125-130. Any ideas or suggestions would be great! Thank you and sorry for the long story.

[mlappin]

Has it ever worked satisfactory or not? If it has worked well in the past but not now, have you ever flushed you flat plate HX?

[slimjim]

 It sure sounds to me that either your water from the outdoor boiler is not moving fast enough or you have some terrible heat loss in the underground piping!

[Ryan]

The piping is buried underground well and fairly new well insulated pex.  I have no snow melt around where the pipe is buried. I have never flushed the heat exchanger it is about 4 years old. The B&G pump is probably at least 8-10 years old, do they get weaker the older the get? I moved to the house in 2008 and replaced the pipe with triple insulated pex in corrugated tubing in 2011, i also put the new 50 plate exchanger in at the same time.  The previous owner had a 20 plate there. I would assume the pump was used prior to 2008 for a couple of years but not for sure. As far as past years go I am not completely sure. I think I was burning alot of propane in previous years.

[slimjim]

Is the ditch wet? Did you cut a drainage ditch? Have you checked the actual gallons per minute flow of your line set? You could very possibly have an obstruction somewhere, an air pocket in the line set or a damaged impeller on the circ.