Amateur Piping Diagram - Critical Input Requested!

David_24

Paul's drawing is certainly close to what I am doing. And when Hot Rod asked if I had a true primary loop, I now understand his question. Like you said, the only boiler firing will be the cheapest available at any given time. My drawing is probably what you might call using a boiler loop as a primary loop. The 3 sources are basically feeding that loop in parallel through check valves. Pehhaps you can tell me why this isn't as good as having a true primary loop, which will require yet another circulator - I can't see a whole lot of difference, if only one boiler is used at a time. ?? Other questions - since I am plumbing the indirectDWH first-off in the primary loop, is it really necessary to set the water up electrically as priority? Also - the house is a very open plan - I'm tempted to run it from one zone and just balance the flows carefully - the thought is, that if I put a bedroom on a separate zone, then there would potentially be so many more boiler firings if the bedroom zone calls at different times than the main zone - perhaps there would technically be no extra energy use, but perhaps someone could comment on that... One fear is - if someone turned the thermostat in that bedroom up, then left the door open, the boiler would just keep firing trying to heat that zone, only to have the heat bleed through the door to the rest of the house. It seems like in certain cases - extra zones might not be desirable?? Dave

David_24

Amateur Piping Diagram - Critical Input Requested

I have the boiler piping schematic roughed out for a house I built for myself. The house is 1500 sq.ft on 3 levels - the SlantFin software says about 18,000 BTU/hr loss. I attached the diagram which was drawn to be a physical placement diagram of the components in the mechanical area - scale is 3"/square - the actual area is just over 9' wide. There are still some items to ad, such as taps for purging and draining - trying to understand where they should go. The system uses 3 boilers (electric dual fuel, propane, and future outside wood boiler connected with heat exchanger). Domestic hot water is by indirect water heater, fired from any of the boilers. The lowest level concrete floor has Wirsbo PEX tubing within (slab insulated from ground), and the upstairs baseboard radiation will be fed with Pex-Al-Pex tubing on a "home run" layout. The outside wood boiler will use a heat exchanger, allowing the water supplies from both systems to be isolated, although water supplies in both systems will be closed-loop antifreeze loaded. Darker lines are 1" pipe. Anyone not familiar with "Dual Fuel Electric Rates" in MN - 3.7c/kwh on a radio meter, but only turned off at breakfast hour and dinner hour - otherwise on all day and night. I think propane would have to drop to 60c/gal to be a better deal.
SO - I hope a few of you pros will take a look - don't be nice - if you see problems, I'd surely like to know before I do it in copper !!! I included a photo of the place I built here, too.

David

hr

I'm not sure

you have a true primary loop there? Hard to tell which pipes cross and which connect.

This is one method. Build a loop all by itself. Then take off with closely spaced tees. Take off the highest temperature loads first. I'd go to the indirect first, although prioritize it anyways. Then the baseboard, then the radiant. Spare tees for an additional buffer when you add a wood boiler.

With this method, any or all boilers could fire at any time, same for the loads. Although it sounds like you will only fire the one with the best energy rates?

The primary pump needs to run when any load, or any boiler input is needed. The 3 way thermostatic needs flow across the closely spaced tees to mix properly, of course.

One downside of series PS boiler piping is.. if more than one boiler is running the downstream boiler will see a higher temperature.

If you plan on running several boilers at the same time the lower drawing would be a better approch (boilers piped in parallel). I left out all the loads for simplification

Any boiler, even non condensing types are most efficient when they see the coolest possible return temperature. It drives the delta t up in the HX, hense the efficiency. The Seisco and GV are both protected from low return temperatures. The GV has this built in.

You may need to protect the wood fired against low return temperatures. This is easily done with a variable speed pump as the boilers circ, or better yet the flat plate HX interface pump. Turns it into a mini injection system, with boiler return protection! Sounds like that is down the road, however.

Control logic will be a bit challanging without experience An assortment of Taco ZV and SR boxes could make it all happen.

hot rod

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David_24

Thanks Hot Rod..

For the nice reply. The only pipes that connect in the schematic are the ones that dead-end into each other - but I should have drawn some little bridges or something to make that clear. Also - my schematic symbols for plumbing leave a lot to be desired - most are probably wrong - such as the check valves (CV)... I'll have logic wired so that only the cheapest available boiler source comes on - wood if on, dual-fuel electric if not, and propane of both are off. Actually, the electronics will be the easy part - I'm an electronic engineer - I can even design my own reset system for the electric boiler using PIC computer chips, and also have designed my own microprossor controller to adjust the thermostat anticipators based on outside temp - all the relay wiring, etc - is a piece of cake - priority for indirect water heater, etc - no problem. But had I plumbed this system without study - I'd have done it like a series electrical circuit and probably screwed up the new GV-3 in a couple years - the PS piping and other tricks are new concepts to us electronic types - looks like short circuits :-) Arrows on the flow paths are probably hard to see - but I did it as you suggected - Watermaker first, Wirsbo in concrete last..
Some questions I do have 1) Do circulators stop flow when they are not running 2)If you connect baseboards with Pex (I'm thinking PAP) - and you only had ONE job to do - would the $350 tool for crimps be worth it, or would compression connectors be the way to go 3) When putting together threaded connections in boiler systems - is teflon tape OK, or should it be the brush compound? 4) If watermaker connections are 3/4", should I pipe with 1" and step down at the inlet/outlet, or just run 3/4" all the way 5( What is the general rule of thumb on where to place drain valves for purging? That's enough for now... THANKS!!! Dave

Paul Rohrs_4

The same but different

This is an older drawing of a system we did a few years back. Again, this is only firing one heat-source at a time. The primary loop must be clearly defined as Hotrod suggests, then "plug-in" the secondary heat-sources (max 6" OC) then run highest temp and load down to low temp. This particular job did not have an electric boiler, but the HO later added snowmelt. Since the HO used an inexpensive CI boiler, he then also added a boiler protection control since it was not as fully automated as your plan. Hope this helps. The only other advise I can offer is not to skimp on isolation valves. (Ballvalves are my preference)

Regards,

PR


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hr

Nice drawing, Paul

send a copy to Mr. Bean He'll know what you are talking about.

David

1) Do circulators stop flow when they are not running 2)If you connect baseboards with Pex (I'm thinking PAP) - and you only had ONE job to do - would the $350 tool for crimps be worth it, or would compression connectors be the way to go 3) When putting together threaded connections in boiler systems - is teflon tape OK, or should it be the brush compound? 4) If watermaker connections are 3/4", should I pipe with 1" and step down at the inlet/outlet, or just run 3/4" all the way 5( What is the general rule of thumb on where to place drain valves for purging? That's enough for now... THANKS!!! Dave

1) yes and no. Be sure to use a circ like the Grundfos Super Brute for positive check protection. PS piping SHOULD prevent ghost flow, but not always. The check pumps are a positive stop.

2) Consider purchasing the tool then resell it here on the BUY and SELL feature. Pencil it out but the cost difference between compression and crimp fittings should work in your favor, even if you discount the tool for resell. Shop that price a little harder though The PAP crimp is a nicer looking fitting, I feel. Wholesalers in my area have loaners.

3) two wraps of "good" teflon tape and a smear of LeakLoc blue is what works for me. Don't overtighten, it's easy to do with slippery teflon. Limit wrench size to 14"

4) I'd use 1" to the indirect, the small pressure drop at the tank increaser won't hurt you too much.

5) I like to put the purge cock right at the PS take off. Webstone, and Watts make some nice valves for fast purge. They are both a ball and purge cock in one valve.

hot rod


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Al Corelli

Paul,

Where did you get that software? I have been looking for drawing software like that.
Thanks,
Al

Ed_13

WM GV series

The WM GV series boilers need to feed into closely spaced tees. Check out the GV manual on their website.