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[RSI]

You can get close going by length and size of pipe (total round trip) number and type of heat exchangers and number of fittings and elbows.
If you list what you have we can try getting a close estimate.

[tbone]

You can get close going by length and size of pipe (total round trip) number and type of heat exchangers and number of fittings and elbows.
If you list what you have we can try getting a close estimate.

8 is pretty close, used a drain valve on my supply line about 20' from my pump to fill 4 gal jugs in 30 secs. While running the pump.  Low tech but it worked...credit willieg.  Thanks for the reply rsi...I was going crazy googlen gpm calculations.

[RSI]

You need really accurate temperature readings to get a good estimate on heat loss. How far is it from the boiler to the house?

[tbone]

100'....taking several readings from each side to get an average

[mw10737]

Im going 150ft. and i didnt use the expensive insulated pex.  I simply used 1" foam insulation the wrapped with foil backed insulation then put inside a 4" sewer pipe. and buried it .  Im only 1 degree diffirent from my boiler to the end of my 150ft.   Seems like 15 deegrees over 100' is a bit high,  but alot of variables.  How is it heating? I have got a 20X28 HX in my furnace and a 12X12 in my garage and also a 20 plate on my hot water heater.  Boiler is set at 180 and with shower going/washing machine/ dishwasher/ aand both furnace running my return line temp is between 18-20 drop.  It works great... plenty of heat.  House is at 74-75, garage is at 70... and hot water never runs out.

[willieG]

your pump must be moving a lot of water

[mw10737]

Willie,  if your speaking in ref. to my post here are my pump specs... just a cheap pump.. but seems to be working great:

Three Speed High Performance Circulating Pump

•Removable Integrated Check Valve
•Built-in motor protection for longer life
•Quiet and low power consumption
•Prevents thermal siphoning
•Pump Housing: Cast Iron
•Voltage: 115 V, 60 HZ. Power: 100/70/55w. Motor: 2 Pole, Single Phase
•Min Fluid Temp: 36° F (2° C). Max Fluid Temp: 230° F (110° C). Max Flow: 21.9 (U.S. GPM). Max Head: 19 feet (head). Max Working Pressure: 145 PSI
•Insulation Class: H 356° F (180° C)


Vendor: Stiebel Eltron

[willieG]

you are heating your home...your garage and your hot water and when you say they are all running you lose only about 20 degrees, that equals good water flow

[martyinmi]

you are heating your home...your garage and your hot water and when you say they are all running you lose only about 20 degrees, that equals good water flow

.....Or very slow moving air handlers. I'm seeing close to 20* loss in my plenum and almost 7* from my gravity fed side arm.

[willieG]

you are heating your home...your garage and your hot water and when you say they are all running you lose only about 20 degrees, that equals good water flow

.....Or very slow moving air handlers. I'm seeing close to 20* loss in my plenum and almost 7* from my gravity fed side arm.

lets say the hot water is being used and it is going through the domestic side at 2 gpm and is only drawing down the water 20 degrees  first off lets say the water is 50 degrees goin into the exchanger and is coiming out at 150 that is 100 degree rise in temp and we know to raise 1 pound of water one degree is 1 btu so we are getting 2 gpm so we are getting (for easy figures) 16 pounds of water, so to raise 16 pounds of water 1 degree we need 16 btu to raise the same amount of pounds 100 degrees we need 1600 btu x 60 min. = 96,000 btu per hour ... to keep our heat loss at around 20 degrees in the delivery from the OWB to the return line we would need almost 10 gpm of 180 degree water, lets say we need another 10,000 btu per hour to heat the house and10,000 more for the shop .that would be another 2 gpm so we need 12 gpm to keep up. 12 gpm is about the max recomended for 1 inch pex

[willieG]

unless of course, it is late and my figuring is way off (can happen)

[mw10737]

Air handlers are running high speed fan( as if AC was on)  seem to have plenty of air movement with both.  pump is 3 speed and i have set on highest speed.  just looked at it again this morning.  Its 30 degrees outside and house is at 74 and garage at 71 and right now with no hot water being used and furnaces running it 12 degree drop.... but keep in mind when its 25-30 degrees out.  My furnaces may only lick on 3-4 times during the day.  If i dont turn my blower on in the garage it keeps it 60 just with heat radiationg of the coil.  House is same way.  It stays 68 with blower off.  Amazing how much radiant heat they put off without blowing air. 

[mw10737]

TBONE talks about his pump not running 24/7??  I think that would be a lot less efficiant  cycling the pump.  Isnt it better to keep that water moving and keep everything hot.  that way when blowers kick on or demand for DWH then you have instant heat?  I would think with it cycling like he is that just getting everything heated up would take alot of heat away.  I can fully understand why hes having such a temp drop.  He should try letting pump run 24/7.  Im guessing he will see a huge improvement.  Tbone.. what are the depth of your lines.  I know someone on here posted that it doesnt help to have lines real deep in ground but in my case im at 5 1/2 ft.  but im also inside a 4" PVC.  Just wondering.  anybody think running it 24/7 be better??

[Scott7m]

Yes running it 24/7 is best.  Many reasons for that.  Back in the old days before good insulated line they all wired the pumps to the inside thermostat so that they wouldn't lose heat to the ground all the time.

Did u get my email?  U can private message me on the board

[tbone]

TBONE talks about his pump not running 24/7??  I think that would be a lot less efficiant  cycling the pump.  Isnt it better to keep that water moving and keep everything hot.  that way when blowers kick on or demand for DWH then you have instant heat?  I would think with it cycling like he is that just getting everything heated up would take alot of heat away.  I can fully understand why hes having such a temp drop.  He should try letting pump run 24/7.  Im guessing he will see a huge improvement.  Tbone.. what are the depth of your lines.  I know someone on here posted that it doesnt help to have lines real deep in ground but in my case im at 5 1/2 ft.  but im also inside a 4" PVC.  Just wondering.  anybody think running it 24/7 be better??

I use a lot more wood running 24/7...maybe when I get new lines I will try it again.  I was off work yesterday and checking my temps.  I forgot to turn my pump off and and went to cut a load of wood.  I only had a few pieces of wood in my stove but plenty to get me through the day as the temps were mild here yesterday.  When I returned home, I checked my stove and It was out of wood.. Then I figured out what had happened.