mtfallsmikey
Addicted to ArboristSite
The sizing table did not come out right
GPM 2-4 Pipe size 3/4"
GPM 4-8 Pipe size 1"
GPM 8-12 Pipe size 1 1/4"
GPM 12 -22 Pipe size 1 1/2"
Pumps, and PEX tubing?
- Thread starter Joesell
- Start date
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The sizing table did not come out right
GPM 2-4 Pipe size 3/4"
GPM 4-8 Pipe size 1"
GPM 8-12 Pipe size 1 1/4"
GPM 12 -22 Pipe size 1 1/2"
stihlcrazy20
ArboristSite Operative
I have a central boiler cl-40, use it to heat a 4200sf house and a 16x80 trailer house. trailer is a 65' run and the house is a 170' run one way. I used the stiebel eltron pumps from menards paid $83 for the small one and $160 for the big one, running them 24/7. For the pex I made my own and have it installed 2 1/2' below the ground. I used 1" Nibco pex from menards and the slip over pipe insulation from there as well. I pushed 2 lines through 4" corrigated tube for each line. My temp drop in my 170' run is a whooping 2 degrees. Total of pex, insulation, corrigated tube, fittings, pex crimper, pumps, and heat exchangers was $1300. Had I went with the central boiler pex and bought the fittings, pumps, and heat exchangers through them it would have cost me over $2500 without installation. Heck of a savings if you have the time and know how to do it yourself. Thought I would throw this information out there for anyone that wants to know how a homemade install works and the savings one can expect on it. Btw, both house and trailer stay at 80 degrees and the boiler gets 18hrs between fill ups.
THE PLUMMER
ArboristSite Member
Pump selection
Always goto a plumbing supply house that specializes in hydronic heating, why? because you want accurate info, unlike graingers. The TDL total developed length of pipe, pipe size and system requirements is required to select the correct pump. Pump selection is very often the biggest reason why systems don't perform properly. The most common requirement is to maintain a delta T of 20 degrees. This achieves optimum comfort and efficiency for air handlers and baseboard heat. Infloor heat requires 10 or 20 DT, depending on if its for warming or heating. The gpm and head specs for the pump have to match your installed systems layout. An easy way to size a pump and cover any discrepancies in measurements and restrictions is to use a delta T controlled pump like the Taco VDT variable delta T pump. You set it for 20 degrees or the desired DT and it will pump accordingly, meaning output will always be 20 deg more than return temp.( read from 2 easy to install sensors). Grundfos is also a good pump but does not have this feature, they have a similar one but it doesn't work like the Taco. You can get them in 007 up to 0013 which will cover any app. Each type of pipe and fittings have their own headloss charts to help calculate TDL for proper headloss. I prefer the Taco pumps, but a properly sized grundfos is just as good and reliable. There is alot to gain by maintaining system design DT. Unfortunately too many overlook this critical part because of laziness or lack of experience, thus compromising a systems efficiency and comfort. Taco is easily rebuilt with a simple cartridge change rather than entire pump. The worst thing for pumps are down time and cavitation. Some electronic controls integrate pump exercising chips , to prevent lock up from being off in the off season. Anything other than a Taco or Grundfos is asking for trouble. Its nothing to get 15-20+ years out of a properly selected pump.
As far as pex tubing goes, always stick with an ASTM approved product with oxygen barrier. Oxygen is the boilers worst enemy, it is what makes a 30 year boiler go in 10-15 years. If you have an open loop system then don't bother with the O2 barrier pipe. Double wall and closed cell insulated designs are the best. Calculating heatloss thru a home made loop is not something you can do in the field. Simply by increasing pump flow can show zero degree loss over 250'. What does it show at 5 gpm versus 20 gpm. Yours might very well be a good design( which can only be tested in the lab for accurate comparison) , but way too often I driveby jobs that have this line from the house to the OWB with no snow and soggy. Wet supply lines have high losses. and why I highly recommend not building your own, as this is a very important part of the system. I know its very expensive, but thankfully many more companies make these insul piping packages. Zurn, wirsbo, stadler-viega are well worth the money. Just find the right supplier. No longer do the OWB's have this market cornered and gouging customers. To high of flow can erode system components and create noise, they also cold shock components by heating too fast and not maintaining a 20 DT.
Always goto a plumbing supply house that specializes in hydronic heating, why? because you want accurate info, unlike graingers. The TDL total developed length of pipe, pipe size and system requirements is required to select the correct pump. Pump selection is very often the biggest reason why systems don't perform properly. The most common requirement is to maintain a delta T of 20 degrees. This achieves optimum comfort and efficiency for air handlers and baseboard heat. Infloor heat requires 10 or 20 DT, depending on if its for warming or heating. The gpm and head specs for the pump have to match your installed systems layout. An easy way to size a pump and cover any discrepancies in measurements and restrictions is to use a delta T controlled pump like the Taco VDT variable delta T pump. You set it for 20 degrees or the desired DT and it will pump accordingly, meaning output will always be 20 deg more than return temp.( read from 2 easy to install sensors). Grundfos is also a good pump but does not have this feature, they have a similar one but it doesn't work like the Taco. You can get them in 007 up to 0013 which will cover any app. Each type of pipe and fittings have their own headloss charts to help calculate TDL for proper headloss. I prefer the Taco pumps, but a properly sized grundfos is just as good and reliable. There is alot to gain by maintaining system design DT. Unfortunately too many overlook this critical part because of laziness or lack of experience, thus compromising a systems efficiency and comfort. Taco is easily rebuilt with a simple cartridge change rather than entire pump. The worst thing for pumps are down time and cavitation. Some electronic controls integrate pump exercising chips , to prevent lock up from being off in the off season. Anything other than a Taco or Grundfos is asking for trouble. Its nothing to get 15-20+ years out of a properly selected pump.
As far as pex tubing goes, always stick with an ASTM approved product with oxygen barrier. Oxygen is the boilers worst enemy, it is what makes a 30 year boiler go in 10-15 years. If you have an open loop system then don't bother with the O2 barrier pipe. Double wall and closed cell insulated designs are the best. Calculating heatloss thru a home made loop is not something you can do in the field. Simply by increasing pump flow can show zero degree loss over 250'. What does it show at 5 gpm versus 20 gpm. Yours might very well be a good design( which can only be tested in the lab for accurate comparison) , but way too often I driveby jobs that have this line from the house to the OWB with no snow and soggy. Wet supply lines have high losses. and why I highly recommend not building your own, as this is a very important part of the system. I know its very expensive, but thankfully many more companies make these insul piping packages. Zurn, wirsbo, stadler-viega are well worth the money. Just find the right supplier. No longer do the OWB's have this market cornered and gouging customers. To high of flow can erode system components and create noise, they also cold shock components by heating too fast and not maintaining a 20 DT.
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