Coalpail.com Forum

Hi I am a newbie and just bought a EFM DF520. My question is the boiler outlet is 3" and returns are 2", what size piping are you guys useing? I got the boiler used and it was reduced down to 1". I was thinking about useing 2" out and the same for return. Any thoughts? Sorry if this was covered in an other thread. Also other than price, is stainless steel a good choice for the piping of the boiler?

Thanks for the help.

Take a look at every boiler you can find. If it was installed properly, both in and out fittings will have a reducer in it. There is a reason for that. 1 1/4" is more often the size used, this can change from a myriad of factors. Best bet is to size it with what the existing/replaced unit is using.

I am going from oil furnace forced air to radiant heat. Detached Garage is 40x60 insulated with 5/8 pex in the floor, that is where the boiler is located and will be running 1" pex to house to feed the manifolds for 1/2" pex in the floor. House is 2200sq ft new construction. Hope that helps answer any question. I did look at all the photos and see that some guy have reduced done to 1" and a couple of you ran larger pipe.

From what you are discribing, it doesn't sound like 1" pipe to heat the house is going to cut it. The pipe size is determined by, how long the pipe run is in that zone and how many BTU's you would like to deliver to that zone.

Read this http://s3.supplyhouse.com/manuals/1350570919940/8 ... D_FILE.pdf

It is the "Taco Radiant Made Easy Application Guide" The BTU output listed on your current oil furnace is a good number to use for the Q factor. You can plug different pipe sizes into the formula to see how it effects your pump size. Very generaly, you can use a smaller size pipe BUT, you then need a larger and more expensive pump to get the heat where it needs to go. The bigger pump also uses more electricity, therefore costing even more.

My guess would be that you need 1.25" or 1.5" pipe for the house zone. Don't forget the PEX pipe needs to be oxigen barrier pipe, you don't want oxygen in the boiler water, it will rust the innerds of your nice little EFM. The pipe also needs to be insulated, http://www.badgerinsulatedpipe.com/ is a good place to get pipe from, nice people and I think price wise are the best. Central Boiler also sells very good insulated PEX.

You should also think about heating domestic water with your EFM. If it doesn't have a domestic hot water coil, get one.

-Don

Thanks Don. I will take a look at that. I was planing on using the DHW coil.