Steel,copper or plastic pex, for 30 ft run between oil and coal

Joe.G

What temps can pex handle?

Joe.G

Hi, I am going to be hooking them up parrael, There is about a 30 FT run between the 2 boilers so there will be about 60 ft of pipe, should I use steel "Black pipe",copper or pex? what size? I was thinking 1 1/4 in.
The run of pipe is going to be in the basement under neith 2 of my childrens rooms, how can I keep the heat from the pipes cooking there room and the basement in the summer? Thanks

Ted Robinson

Caution with PEX

I suggest you look very carefully at the maximum, maximum possible temperature that the PEX could be subject to, especially from some unusual operating conditions.

Joe.G

Can anyone help me with sizeing?

World Plumber

primary seconday zone

Have you considered using your oil boiler as a zone off your coal boiler. Heat you oil boiler with the coal, set you triple aquastate down for second stage use aquastates to control a pump that will circulate the coal boiler water through the Oil boiler, or you could use constant circulation with temp control on the coal boiler when the coal boiler is hot and the temp in the oil boiler is below the desired operating temp. Your home heating system remains intact. You want to use some control ie: the aquastate mentioned above so you don't circulate water when the coal boiler is off.
As per sizing how many BTU's does your home require to heat it. We have been using 1" pex with the outdoor wood burners connected this way.
Why would you have the boiler on in the summer. If your heating demestic hot water then insulate the piping well

Joe.G

I was planning on useing it to heat domestic hot water, but I may just use the oil boiler for that this way I can leave the pipes unisulated and it will heat that section of the basement.

I plan haveing a circulator run constant between the 2 boilers. I will set teh coal boiler at 180/160 and set the oil boiler at 150/130 an dhopefully never have the oil boiler come on. You are saying that I can get the circulator ( the one that just circulates water between the 2 boilers) to shut off at some point how? thanks

World Plumber

Stop circulator

To have the circulator go off you need to install aquastates. Probe tyoe is best but strap on's close to the boiler will work Use one that opens on low temp on the coal boiler to break the power and stop the circulator if the boiler is not hot. If you circulate water when the oil boiler is running you will be heating a lot of extra water.
If you want the circulator to stop when your oil boiler reaches a high temp install an aquastat there that opens on rise and wire in series. That way your circulator will only run when the oil boiler need to be heated and won't run if the coal boiler is cold. On constant circulation if your coal boiler goes out you oil boiler will be working to maintain temperature in your coal boiler. You really don't want that unless it's outside and in danger of freezing.

Mark

World Plumber

For domestic hot water if you want to spend the money up front you could take a secondary zone off the coal boiler and use an indirect water heater of a plate heat exchanger. That way you won't have hot lines running across the basement. You may have to run your water to get it hot if it's far away or recirculate your domestic hot water so it's always hot. There are a lot of options. I'm assuming you have a tankless coil in you oil boiler.

Joe.G

Both boilers have coiles, but I use a indirect water heater.

Joe.G

BTT