outdoor boiler hookup?

[mjs97]

need some advice guys. i have a built a outdoor boiler that holds around 200 gal. with forced air draft optional. i have put it about 20 ft. outside my garage and ready to start plumbing. my house is 1500 sq.ft. and garage is 1100 attached, also want to hook side arm into water heater. i am thinking of buying line from central boiler dealer ($11 per ft.) to run to garage. then installing pump on supply line there and then running regular pex line to sidearm in house(inside garage) then to acoil in furnace then back out to garage thur acoil then back to boiler. pump is 8 gal per min. house and garage are well insulated.

can i heat this much with one zone?
should i insulate lines in garage running to house and back, if so with what?
do i need anti freeze in boiler?
does it really take that much more wood with antifreeze?
what if pump dies and water quits circulating?

thanks,
matt

 

[MS-310]

You should be ok with that size of pump unless your going up a grade or up in the walls far. I have seen those pumps do some stuff that I would never think it would work and so on.
Yes if your pump stops working and you dont put wood in it and its so freaking cold it mite freeze, you will know when your pump stops working.
Plus anti freeze for a boiler is not cheap at all.
Do not use auto grade anti freeze, it will hurt the boiler in time, seen it done not cool.
I would but some black pipe foam on the pex line in the house and garage to prevent sweating in the summer and to help keep the heat where you want the heat.
That stuff from cental boiler is sweet but 11 bucks a foot is alot, but worth it.
DId you get that love control working, sorry I didnt call you back matt.
Jack

 

[mjs97]

yes that love control is sweet. especially for the price. i can't thankyou enough for your help.

i just get nervous thinking that something could happen and have that boiler freeze and crack. that would really suck.

i can heat that much stuff with one zone though you think. really don't want to have to run more lines to garage.

thanks,
matt

 

[MS-310]

You will be fine with that much load on the one set of lines.
It will work just fine, I wouldnt be worried about frezing the stove.
Jack

 

[lilpig]

You built it?!

I've been looking into these things and they cost an arm, leg and several other parts. You said you built one? Did you do it from scrach (really hard to build anything from scraching) or was it a kit?

 

[shalx]

Keep in mind "regular" pex will allow oxygen to infiltrate system and corrode everything from inside. So only non ferrous components or oxygen barrier pex. Good heat systems should be done once. With only one loop zone you run the risk of not being able to keep the heat where you want it, warm house cold garage best case warm garage cold house possible as well. With one big zone you start looking at large temperature differences (delta T) from supply to return good for efficiencies but condensing a boiler not meant to condense leads to very short lives for equipment. With a 200 gallon capacity you should not have to worry about thermal shocking as much. As for your domestic water separate priority zone and largest pump you want bigger here is MUCH better. Faster recovery times and no downsides to efficiency.

 

[mjs97]

i biult it by scratch pretty much. looked at several and took the features i liked from each and incorporated it in mine.

i am thinking of leaving trench open for a while and get everything running under load first. then if i have any problems i can add another zone (another set of pipes) without having to dig up lines. i am told that more than 40 degree temp. drop is the max. more than 40 need another zone and pump coming off stove.

thanks,
matt

 

[MS-310]

Keep in mind "regular" pex will allow oxygen to infiltrate system and corrode everything from inside. So only non ferrous components or oxygen barrier pex. Good heat systems should be done once. With only one loop zone you run the risk of not being able to keep the heat where you want it, warm house cold garage best case warm garage cold house possible as well. With one big zone you start looking at large temperature differences (delta T) from supply to return good for efficiencies but condensing a boiler not meant to condense leads to very short lives for equipment. With a 200 gallon capacity you should not have to worry about thermal shocking as much. As for your domestic water separate priority zone and largest pump you want bigger here is MUCH better. Faster recovery times and no downsides to efficiency.

If its an open system o2 pipe wont do a dam thing for him.
He will be fine with one zone.

 

[windthrown]

Some feedback...

I installed our Central Boiler unit here last year with std. one inch PEX. CB does not recommend Ox barrier PEX, nor does anyone else that I talked to around here. CB has an open system boiler (non-pressurized) so Ox will get in there anyway. CB gives you corrosion inhibitor with the boiler to add to the water to protect the steel in the boiler. One gallon of that stuff lasts over 3 years.

I would not use antifreeze in your boiler water for several reasons. One is that with 200 gallons the boiler is not apt to freeze becasue of the thermal mass. Another reason is that if you run the boiler loop into the house and your water heater, the HX on the heater will reverse and contribute heat to the boiler lines, keeping them from freezing. Lastly, antifreeze will reduce the thermal heat transfer of the water. In other words, antifreeze makes the water a worse heat conductor. I do not know how much worse, percentage wise. So I cannot say how much more wood you would have to burn if you used it. As some others here said, do NOT use ethelyne glycol (automotive antifreeze). It is poisonous. If you must use antifreeze, use propylene glycol in a 50/50 mix with water.

As for zoning, I have a one zone system here. It is expandable to two zones if I want. I heat the water heater HX first, and then the floor heating HX. The pressurized floor heat loop has a mixing valve to keep the hydronic floor temp at 100 degrees, so the temperature of that can be lower. Hence the water heater HX before the floor loop HX. I am thinking of adding a water-air HX in the garage after the floor loop HX on the return line to the boiler to squeeze out some more heat. All from one zone.

As for a pump failing, or a boiler-over... depends on the design of the boiler. With a CB, the system is open. Also if there is a power failure, the damper will close automatically (solenoid pulls the damper up and open, gravity will close it if the juice is shut off). Same with pump failure. Water will get hot, damper will close. No biggie. You will notice the problem when the house gets c-c-c-cold though. Even if the boiler boils over, it is an open system and the water just bubbles out of the top, taking the excess heat with it. Main reason I went with an open system boiler is the safety factor. We have 2 Taco pumps here. A 700 drives the boiler loop and a 900 drives the pressurized floor loop.
:rockn:

 

[windthrown]

Ps...

Oh yah, and about your question about insulating the PEX lines in the garage? I used slip-on pipe insalation that comes in 10 ft lengths for that. You should insulate all the PEX lines inside (and outside) the house. On the PEX run outside the house/garage to the boiler I shoved the insulated PEX lines into a 4 inch drain pipe to waterproof the lines. Most people say thet the real heat losses in buried PEX lines is from groundwater. Keep the water away from the buried and exposed lines and you will be fine.