About to crack into the oil burner - questions and help.

[MrEd]

OK, I am just about to do the part of the install that has me the most nervous, that is cracking into my existing heating system to pipe in the flow and return from storage and the Tarm.

In the attached picture, the top graphic shows the top of my existing (and old) oil burner. My plan is to break into the supply from the oil burner where I have put the yellow arrow. Besides getting in a 1.25x1.25x1.25 tee into where I have put the arrow, should I be putting in a flow check of some sort? My guess would be yes as I don't want the tarm circ to push water backwards thru the oil burner..

On the bottom graphic I need help determining where the "T" for the return should go, I am thinking to the right(before) the circ...what I am not sure about is what is do I also need some sort of flow-check at this point?

On both connections I plan on putting 1.25 ball values so I can essentially tap-off the complete wood boiler from the rest of the system if needed (i.e. for maintenace). Would you also recommend purging/draining valves at those connection points as well?

Last question - any of you guys that have cracked into pipes that have problem remained in place for 20 or more years - how much fun am I in for? I have 2 24" pipe wrenches, and a few "persuader pipes" if I need more leverare, but is there a trick to getting old pipes to open up without breaking anything?

BTW: I am using a modified version of the "Simplest pressure storage setup" that nofossil created.

 

[steam man]

With the info we have I do this-remove the elbow at the top of the oil boiler and install a tee with the Tarm flow going straight through. You have a union there you can loosen and reuse the same threaded nipple. At the return side I would go before the pump just below the union that is already there. I presume the Tarm will have its own pump either with an internal check valve or have a separate one to prevent back flow. It looks like the oil boiler will need a check valve. Does its pump have one installed? That being said take note that when I start a big project on a weekend I always need something I can't get. You may need heat to help get those fittings/pipes apart.

Have fun.

Mike

 

[MrEd]

The Tarm does have(will have) its own circ with IFC, the old boiler does not. Would the appropriate place to put this new check valve be the same place as you suggested to cut in the return for the tarm?

You may need heat to help get those fittings/pipes apart.

You mean help as in more muscle? or help as in someone that knows what they are doing?? Conceptually it doesn't seem that hard, what I really worry about is cracking something.

 

[hossthehermit]

Hi, just browsing here, hang on pellet forum more. MrEd, I'm not a pipefitter or boilermaker, but based on what I do know, I would talk to a pro about the wisdom of using ball valves in this setup rather than boiler (gate) valves. Just an observation, sounds like a well designed setup, but it's the little things that will getcha. Good luck, stay warm

 

[steam man]

Sorry about the delay responding. I wouldn't be concerned about using ball valves. That's about all I use. They are rated for the temp and pressure. Just use full port ones.

You don't seem to have a lot of space for adding a check valve in a required positon. If your oil boiler circ doesn't have an internal flow check you could consider replacing it with one that does. Barring that you could re-pipe the return side to kind of " loop around" to add enough length to the return side to add a check valve. Before or after the pump shouldn't matter though I would probably use the discharge side.

In your pictures I don't see an expansion tank-where is it? You'll need to add expansion capacity because of the increased volume of water with the wood stove.

What I meant by "heat" was maybe an oxy-acetylene to heat the fittngs/threads to help break the corrosion bond. Since that isn't probably available, you have to at least be able to get the fittings apart at the boiler with no damage to the boiler. After that, if a fitting was impossible to separate, I would just go back to wherever the first fitting would loosen and replace everything from there to save time.

First rule of thumb-"Do no harm".

Let us know how it goes.

Mike



Mike

 

[MrEd]

Sorry, mis-read your post - I thought you said I would need "help" to loosen the joints, not "heat to help"....in any case I do have a small torch I have put into use, but didn't seem to help much.

I did get the pipes cracked open at both places. I loosen up the union on the top of the boiler and got the approximately 6" nipple out, but can't see anyway of getting that elbow off. Just not in a place where I can get any real leverage (I used a 5 foot bar on my 24" pipe wrench just to get the nipple out; so, even thought I like the idea of piping the flow from the tarm straight thru, I may add a "T" where the 6" nipple was, and plumb the feed in that way. Think that will cause any problems, or problems bad enough to justify struggling trying to get that elbow off, or worse breaking something?

On the return side I open up the union where you suggested (on the bottom picture the higher of the two blue painted joints).

Here is the flow-check I was considering using:
http://www.pexsupply.com/product_dtl.asp?pID=4&brand=Matco-Norca&cID=3

Doesn't seem that big to fit in, but I am also considering just replacing the pump with one with an IFC to - good suggestion.

The existing expansion tank is mounted in the rafters above the boiler - its the old fashioned steel kind w/out a bladder. The tarm will have a new modern exp tank, and when storage comes on line it also will have a seperate expansion tank.

 

[steam man]

Don't break anything. The tee could go where the elbow was. It would look a little odd and it will restrict flow a little but it will work. Fittings that size need alot of heat and a small torch won't do it. You really need to be dull red at least and that is hard to get without O2. The 5' cheater sounds dangerous. A pipe wrench breaking is not a pretty picture. The swing check you noted would have to be in a horizontal position though I like the IFC idea the best.

Mike