piping a second boiler to my primary loop

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Old 03-09-13, 05:55 PM
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piping a second boiler to my primary loop

I am in the process of adding a second boiler to my primary loop. My origional boiler is a Trianco-Heatmeker. The new (and primary) boiler is a Burnham RV4 gas fired. Below is a rough sketch of how I was planning on running the piping. Any recommendations would be appreciated. http://imageshack.us/a/img593/6620/scanqr.jpg
 
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Old 03-11-13, 06:13 AM
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Your not planning or need to have both boilers run at the same time ?
 
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Old 03-11-13, 12:03 PM
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No. They put a gas well on my property and there is no backup gas if they need to shut the well down to work on it. So the old oil boiler is just there as a backup
 
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Old 03-11-13, 02:36 PM
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Chip, I believe if it were mine, I would think about something different...

I would run a primary/secondary loop, with it's own pump...

The heating loops would be closely spaced tees off that primary loop, each with a mixer valve (since they are both radiant.

The two boilers I would probably cut into the P/S loop each on closely spaced tees, and each with it's own pump.

If I get time I guess I could scribble on your drawing later...
 
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Old 03-11-13, 04:15 PM
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NJ Trooper, any help would be appreciated. Ive been seeing the closely spaced tees in a lot of different places. I can't say I understand the concept, but i'm not going to argue with proven science. MY new boiler will run at 210 so i guess having a mixing valve on each zone will negate the need for another limit. I can do the work no problem, its just a matter of getting a schematic. Thanks for any help you could give me.
 
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Old 03-11-13, 04:32 PM
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MY new boiler will run at 210
WHAT? WHY?

No... your new boiler will run at 180.

210 is crazy hot, not necessary.
 
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Old 03-11-13, 04:52 PM
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It has a notice plastered right next to the aquastat that says "don't set below 210" The installation guide does say that if using a lower temp system I can add an L4006
 
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Old 03-11-13, 04:55 PM
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This is sorta what I had in mind... basic concept:

Yes, it's an extra couple pumps, but there are no valves to open/close, no margin for error... whichever boiler is powered up will run.

You would need some sort of switch to direct the heat demand to one or the other, but that's easy.

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Not 100% sure about which direction the pumps in/out of the boilers should be... maybe on supply and not return? TO? what say you?
 
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Old 03-11-13, 04:57 PM
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It has a notice plastered right next to the aquastat that says "don't set below 210" The installation guide does say that if using a lower temp system I can add an L4006
You have the boiler already?

Make/model?

Online install file location?

Wait... never mind... I see it's gonna be a Burnham RV4... I can find.
 
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Old 03-11-13, 05:05 PM
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The RV (Revolution) series isn't current production... is it new old stock maybe?
 
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Old 03-11-13, 05:34 PM
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The RV (Revolution) series isn't current production... is it new old stock maybe

I bought one of the last 8. I bought it because it has tha internal primary loop that I think will make it easier to hook up to my hydronic system. (thats what they claim)

You would need some sort of switch to direct the heat demand to one or the other, but that's easy.

Yea I got that part figured out
 
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Old 03-11-13, 05:38 PM
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I'd definitely do it primary/secondary. Maybe even toss in a buffer tank in the boiler loop if you have the room.
 
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Old 03-11-13, 05:43 PM
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Maybe even toss in a buffer tank in the boiler loop


one of those big steel tanks i sometimes see strapped between joists?
 
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Old 03-11-13, 06:01 PM
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No, that would be an expansion tank. A buffer tank is merely additional water heated to forestall "short cycling" of the boiler's burner. It also acts as an excellent "division point" between the boiler and the heating system proper. With two boilers, each piped separately to the buffer tank, you will be able to easily run either boiler to its maximum output with no other problems. In addition it makes it easy to have different (lower) temperatures for the heating loop with minimal controls for greater comfort. Since the primary fuel is going to be free, or very low cost, ultimate system economy is a lesser consideration.

The biggest concern is the added space in the equipment room it will require. There is also the capital cost of the tank and insulation.
 
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Old 03-11-13, 06:50 PM
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The biggest concern is the added space in the equipment room it will require.


How big of a tank are you talking? Space is very limited. I could take space from another room but would rather not.
 
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Old 03-11-13, 07:17 PM
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My background is commercial and industrial sized equipment, not residential, so I prefer big. My preference would be for nothing less than a 40 gallon buffer but even a ten gallon tank would be better than the closely spaced tees. But let some of the residential specialists help you make the final decision.
 
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Old 03-11-13, 07:20 PM
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so would that be to increase the thermal mass of the system?
 
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Old 03-11-13, 08:30 PM
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Yes, it increases the thermal mass of the system but it also makes a better connection arrangement for the two boilers to the system.
 
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Old 03-12-13, 05:22 AM
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Google up "Boiler Buddy" for a bit more info on buffer tank.
 
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Old 03-12-13, 11:46 AM
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The buffer tank is very interesting but I think I will opt out because 1) My new boiler is the same size as the old boiler and I didn't have a problem with short cycling (especially with the basement zone in concrete) 2) I am not worried about ease of piping 3) The old boiler will most likely never be used ( I have talked with folks in similar situation who took out the spare boiler after years of non use)

I have seen the bit about the use of closely spaced tees everywhere and dont understand the concept compared with the way my boiler is presently piped. Could anyone give a simple explanation in laymans terms?

http://imageshack.us/a/img833/1551/dscf3172w.jpg
http://imageshack.us/a/img259/8872/photo2233749515.jpg
http://imageshack.us/a/img62/4958/dscf3174v.jpg
http://imageshack.us/a/img32/889/photo3ykc.jpg
 
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Old 03-12-13, 12:42 PM
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I think I will go against everything here LOL.
The way you have drawn it is fine, as you do not need any automatic change over or 2 boilers to heat the place.
There is a ton of mass in the rev, no need for more storage IMHO.
I don't see any need to complicate things.
 
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Old 03-12-13, 11:00 PM
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Just a random thought or two on chip saying many removed the backup due to non use and the fact that his gas is on his own well not supplied by local utility. Looking at it from a back-up generator kind of view. Maybe a backup is a legit concern.

What are the options of keeping current setup and just installing a gas conversion head, clean up all settings on oil head and put safely in a box to convert back if needed. A couple bolts and wires and back to oil.Unless you want/need new boiler.

What about putting new boiler in and order the propane gas valve? Put a propane tank on the side of house for emergencies. Pipe both valves at the same time with a switch or does it need a whole different orifice/nozzle setup?

Get a CNG/LNG tank on the side somewhere with some shut off/isolation valves. Flip the valves work on well and go back.

Going on the "keeping oil for back up". How often will you flip those valves and run it? I'm thinking like my snowblower where all fuel needs to be drained or it gums up every year. My generator I run 15 minutes/month to make sure it works when needed. Looking seriously at a propane version so I don't need to worry about gummed up carb.

My cousin in MA has propane and has a huge propane tank buried that they fill twice/year. What is storage/shelf life on fuel oil/propane/CNG?
 
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