How do I connect a coal boiler to an oil boiler?

Ok, I am looking to place a Losch 475 in my garage and circulate the boiler water into my ThermoDynamics oil furnace. It is approx. 35 feet from my basement wall to my garage wall. My garage is approx 36L x 42W. I plan to place the Losch in the back of the furthest bay from the house due to stairway to second floor and other things that would be in the way. This makes the total run about 80 to 90 feet.
Questions:
What do I use for piping? I see preinsulated pipe but cant I get uninsulated and insulate it for less $$$?
Do I run the pipe underground from the house to the garage (shortest route) and then go accross the garage inside or stay underground and trench around to the location of the Losch?
What controls are needed to do this the "right way" as in not have the circulator always running between boilers? Do I run a temp sensor from the oil furnace out to the aquastat on the Losch?
What is the best aquastat to use with a coal boiler?
Where do I get a mercury timer to maintain the fire? I am told these are better then other timers. Is this true?

vwgtiman wrote:Questions:
What do I use for piping? I see preinsulated pipe but cant I get uninsulated and insulate it for less $$$?
Do I run the pipe underground from the house to the garage (shortest route) and then go accross the garage inside or stay underground and trench around to the location of the Losch?
What controls are needed to do this the "right way" as in not have the circulator always running between boilers? Do I run a temp sensor from the oil furnace out to the aquastat on the Losch?
What is the best aquastat to use with a coal boiler?
Where do I get a mercury timer to maintain the fire? I am told these are better then other timers. Is this true?

I would use what you have already in your home, if copper, copper. If iron pipe use iron pipe. I would not buy pre-insulated, too expensive. You can shop around for the stuff to bury between the house and garage, there are a few types to choose from. I would go the shortest route underground to keep the cost down unless you have some issues in the garage with plumbing. For controls generally a temp switch and relay will work. The boiler should come with the aquastat it needs. I don't think you need a timer.

Thanks for the reply. My oil furnace is piped with 3/4 copper to 3 zones in my home. Are you saying use copper from the oil furnace to the point where I would use PEX underground to the shortest distance to the garage and then go copper again? I am thinking that it may be less $$$ to go with PEX all the way from furnace to furnace.
Is it cheaper and still effective to insulate on your own instead of buying pre-insulated?
What is the best method to insulate on your own pipe?
How bad is it to use a non-oxy barrier PEX product? It looks like the oxy barrier PEX is 3x the price. Not sure its worth the up front cost is it?
I also see that 1" may not be good enough in some posts... Wont 1" PEX with fittings be much less then 1" inside diameter?
Will an Taco 007 be good?
Is speed of water better then volume for limiting loss of heat between buildings?
I plan to heat my garage also or at least part of it.

Also, I was told by a few Losh users that a mercury timer is the best way to keep the fire in a Losh. Is there any other Losh users out there that could tell me how their stokers are set up? The aquastat, timer, and temp/pressure guages were destroyed when it was yanked out of its home.

I would say it is cheaper to insulate yourself, you may want to leave it uninsulated in the basement to warm it up. The buried plumbing must be insulated very well. There is a lot of info here on the forum for a project like this. Lsfarm Freddy and a bunch of others have done this type of install with great success. I think you really need 1 1/4" between the boilers, 1" @ minimum. I don't know much about PEX, there are a few experts here, I hope they chime in. I would not use it without the O2 barrier. I don't know what to tell you about the mercury switch other than Losh still has parts and if that is what they came with I would use it. The Taco 007 should be up to the task.

Oxygen barrier is a must with Pex pipe. I used 1" Pex al pex for an application similar to the install you are doing and have been very satisfied. Sizing for Pex al pex is approximately the same as copper while 1' pex is more nearly the inside diamer of 3/4 in copper. If you go with pex with an oxygen barrier--which I don't recommend -- you will probably need 1.25 inch.

The advantages of Pex al pex over pex with oxygen barrier are:
1. Pex al pex handles much like soft copper--you aren't constantly fighting the memory of the coil when installing;
2. Pex increases in length significantly when heated and this is factor you must take into account in the install. Pex al pex is very stable with changes in temperature; and
3. The oxygen barrier is internal with pex al pex so it is protected during handling and installation. The oxygen barrier with pex is an external coating that can be damaged during installation and can also be damaged by the expansion/contraction that occurs with temperature changes if the pipe rubs against something when expanding and contracting.

I did an underground installation. About 40 feet underground and another 35 to the oil boiler. I wanted pex al pex, but had to settle for O2 barrier. The 1" pex-al is larger inside than the 02 barrier. I don't think one loop of 02 would do the job. I ran two loops of it. I insulated it myself. Much cheaper and it seems to work OK. I cannot measure a temp loss from coal boiler to oil boiler. I covered each pipe with that 1/2'" thick black insulation, then bundled the four together and wrapped with that foil bubble wrap. They went inside 6" sched 20 PVC. One thing I knew, then one I discovered.... I knew that wet insulation losses ALL insulation value. I discovered that underground pipes eventually fill with water... from condensation! Luckily I left a clear plastic tube in the underground pipe in case it leaked. I never imagined I'd need to to remove condensation. After I realized what it was doing, I sealed both ends with foam in a can & the condensation dropped to almost zero. So....make sure your underground pipe tilts one way or another so water can drain out of it.

The next thing....pex is only rated 180 or 190*. I added mixing valves because often times the coal boiler would be way over 180*. Now the Pex never sees over 180.

I used the existing pumps to move the water. They only run when there's a call for heat.

I do not think you will find a mercury timer. It's been outlawed. The new timers are just fine.

Freddy wrote:The 1" pex-al is larger inside than the 02 barrier. I don't think one loop of 02 would do the job. I ran two loops of it. I insulated it myself.
The next thing....pex is only rated 180 or 190*..

Freddy, just curious.... Two questions for when I goto install a coal fired boiler:

1) Why didn't you go with a single loop of 1 1/2" or 2" dia pipe? Why two loops of 1"? I believe you have 3 or 4 times the volume in a 2" , with reduced restriction, than a 1".

2) If your worried about the pex overheating temp (190F), why not use copper? Expensive? Yes. But it solves the worry of overheating it.

Thanks.

Freddy

Thanks for the info. Can you tell me how you have the two systems tied togeather (coal and oil) as it sounds like this is what you are doing? Do you run any sensor lines between the two systems or do you circulate 24/7?

It really depends on what you want it to do, they can be connected in series or parallel.

Looking at a local persons outdoor woodburner setup I think I know what I will do. His setup is quite simple. He runs 1" feed and return lines (approx 200' total loop) with a Taco 007 running 24/7. The water circulates into his oil furnace boiler tank (in top, out bottom). According to him, electricity usage of 007 is minimal and oil never is needed. To further simplify the installation he does not have an expansion tank or water feed on the woodburner. Expansion is addressed and addition/regulation of feed water come from the existing oil furnace.

most out door wood boilers are open systems and your oil fired boiler is a closed system you should probably think about using a flat plate heat exchanger if this is the route you plan on taking

one inch pex will only carry 80,000 btu of energy in a trouble free design.

Are you sure that's enough to heat your load?

Remember I wrote --- "In a trouble free design"

Sting wrote:one inch pex will only carry 80,000 btu of energy in a trouble free design.

Are you sure that's enough to heat your load?

Remember I wrote --- "In a trouble free design"

Please explain? I know that the diameter of the pipe along with flow resistance and rate will decide the btu amount but are you saying 80k is tops or 80k is what to expect out of this?

Sounds like you need more help than a simple answer. That's not a bad thing.

Here is some suggested reading to get you up to speed.

http://www.heatinghelp.com//shopcart/pr ... gory=8-208

Kind Regards
Sting