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The great piping fiasco? Need help!

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by RowCropRenegade, Jan 4, 2010.

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  1. RowCropRenegade

    RowCropRenegade Feeling the Heat

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    Russ,

    My unions are not dielectric. Won't hit copper until 100 feet away in the oil boiler room. Probably right out of hx will be dielectric unions. I

    A question about your system... besides the taco delta pump, there is another pump on your old boiler loop? If so, where is it at?

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  2. deerhntr

    deerhntr Member

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    If you look at my diagram with the heat exchanger you will see a supply manifold on the top of the existing boiler. That supply manifold supplies 6 zones. Each zone has a pump, pumping away from the boiler into the load, and returns to the return manifold on the left side of the diagram. My existing boiler is plumbed with just the supply and return manifolds. No primary/secondary.

    Hope that helps.
  3. Gooserider

    Gooserider Mod Emeritus

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    Hopefully someone with more Garn expertise will tell me if I'm wrong, but my understanding of the reasoning behind return water temp protection and the way a Garn operates, is that a Garn really doesn't need that sort of protection, and you are going to get the best performance if your return water is as cold as you can get it (from using the BTU's to heat with, of course, not just running the water through a cooler...) In theory at least, and possibly in practice if your loads were mostly low temp radiant circuits, you could cycle the Garn tank down to around 90°F or so, well below the normal condensation temps, and get really high efficiency on the reheat burn...

    In a standard gasser or other cast iron boiler, the return water pretty much blasts against the inside wall of the firebox, and if it's cold, can cause concentrated flue gas condensation at that one point, with subsequent corrosion, and so forth. Thus protection is needed to ensure that the return water is above the condensation temp, about 140°F...

    With the Garn, the cold water just flows into the giant tank, where hopefully it stratifies and pushes the warmer water towards the top of the tank for use - when the entire tank is cold the unit is fired, and the firebox and exhaust tubes get heated, and are mostly surrounded by a layer of the water they are heating, which keeps them above condensation temperature... Any cold water returning to the tank during the firing still mixes into the bottom layer, and doesn't impinge on the firebox, so there is no condensation issue - if no condensation, no need for protection...

    Gooserider
  4. RowCropRenegade

    RowCropRenegade Feeling the Heat

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    This is the best I've had it explained to me. I didn't realize the protection was for the firebox itself. Low temp water is what we want at the bottom of the tank. This explanation helps me comfortable elminate the need to plan for a mixing valve on the primary loop. Thanks Gooserider!
  5. Scott from Canada

    Scott from Canada New Member

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    That is exactly what Ken from Garn told me. No mixing valve required on the return line at the Garn unit. Keep up the good work you guys, I am still in the planning stages as while my 1500 sits on my trailer.

    Scott
  6. Jim K in PA

    Jim K in PA Minister of Fire

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    Sorry Reed, I did not pick up on your intent of the mixing valve on the back of the GARN to be for low return temp protection. Goose is 100% correct, the GARN has such a large volume of water, and is configured to stratify nicely, that no low return temp protection is needed. The large tank is a buffer, and you can run it down as far as you want (and can get usable heat from).
  7. RowCropRenegade

    RowCropRenegade Feeling the Heat

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    Thanks for helping make my elimination of the mixing valve.

    Jim, I know you talked about moving your primary loop pump lower, did you ever move it? If so where to?
  8. Jim K in PA

    Jim K in PA Minister of Fire

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    I did not move the whole loop this year, as completely re-piping the house side was more of a priority, and took longer than I had planned. The house side was also more important than the GARN side to address. I did, however, move the pump about a foot lower by just swapping a pipe section. It is now about 12" lower than last year, and almost even with the bottom of the tank of the GARN. The secondary pump(s) are still at the same level, and I want to drop them too. I will revise the primary next year when I incorporate the propane backup loop. So far, I have not exceeded 200 more than once or twice, and have not detected any suction boiling.
  9. RowCropRenegade

    RowCropRenegade Feeling the Heat

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    Maybe I'm nit picking each detail but I dont want to have to go back and do it again.

    What I don't like about my planned system right now, is those pumps. I figured they would shut off when the delta T was below 20, not the case. They run at low speed. So basically when the zones aren't calling for heat, the primary and secondary pumps will be running at low speed, just siphoning btus out of the garn. Maybe its minimal enough to not worry about. Any thoughts?
  10. deerhntr

    deerhntr Member

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    Reed,

    The pumps will only be on if your TSTAT is calling for heat, Then the pump will adjust to deliver the BTUs required to meet you delta T setting. As long as your load needs BTUs, the circulator will operate and deliver BTUs. If the pump adjusts down to the minimum speed, and your TSTAT is still calling, the only wasted BTUs would be the difference between the amount required by the load,and the extra delivered at the minimum speed. If the speed required is the lowest trickle, then that is where the pump will operate. The pump does have an exercise mode that if it has not been run is 72 hours, it will run for 10 seconds.
  11. Jim K in PA

    Jim K in PA Minister of Fire

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    What he said :lol:

    Seriously - your pumps should be controlled by a relay with signal from the t-stat(s). My primary & secondary pumps only come on when there is a call for heat.

    Just for giggles, yesterday I went and checked the supply and return temps on the primary loop and the secondary loop for the house. It was in the mid 20s outside. Garn tank temp was ~172. ΔT on the primary was EXACTLY 10°F with the 43-44 set on low. ΔT on the secondary was within .1 degrees of 20°F with the 26-99 also set on low. I have a pair of Azel temp units in the garage with sensors strapped to the piping. Not too shabby, I think. :coolsmile:
  12. RowCropRenegade

    RowCropRenegade Feeling the Heat

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    Thanks Russ and Jim!

    ok, that makes a whole lot more sense. - adding the relays. They turn the pumps on and off depending what the tstat says. Glad I asked this question. Got backhoe fixed yesterday, digging a trench tomorrow. What type of wire does the tstat use to communicate with the relays?

    I was hoping to make it through this project without doing too much wiring. wrong again!
  13. deerhntr

    deerhntr Member

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    Reed,

    Thermostat wiring is usually 18 gauge, solid copper, multi-strand(Typical 4). I recall you mentioned that your house had one TSTAT that controlled you existing boiler. There should be some control wiring from that tstat to some type of relay on your boiler. From there the relay(or relays) switch on you boiler, and associated circulator. Check out the wiring that you already have.

    You may need to install a zone control board similar to a Taco SR-503. This is a 3 zone controller with priority for example. Taco has a very nice guide, 95 pages long, at Taco Wiring Guide that has a number of examples, a glossary, and other useful information.

    You may want to locate you zone controller in the GARN room, then route control wiring to/from the loads. That may require additional single switching relays at the circulator locations like a Taco SR-501.

    Good luck, it will all seem simple when you look back this time next year!
  14. Gooserider

    Gooserider Mod Emeritus

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    What I suggest, and have seen many others do likewise is to drop a couple of 3/4" conduit runs in the trench along side the water pipes - either official PVC NMT, or I've heard of people using non-porous irrigation pipe, or equivalent - this better protects the wires, and allows easy modifications and changes in the future. What many folks do for wiring is use Cat5 or Cat5e computer Ethernet cabling - it's a little lighter weight, but you get 8 conductors per strand, and data wires don't normally carry any significant current, so it should work fine - if you do need to up the current capacity a little, just use two or more strands tied together...

    Note that if you will be running AC power lines as well, they may NOT be run in the same conduit as your data cables, and if possible the AC conduit and the data conduit should be kept as far apart as possible... This is for both safety and data-quality reasons...

    Gooserider
  15. RowCropRenegade

    RowCropRenegade Feeling the Heat

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    Russ, I was hoping to leave the old boiler controls alone. Set that thermostat lower at like, 60 degrees. I'm hoping that the only relays I will need will be for the main manifold and each secondary loop pumps. Still investigating the best route to go with the current boiler. I suspect I'll go ahead with the basics just to get the unit going, then go back and add all the relays, maybe outdoor reset. It's all so vague still. I'm sure you are right about it being simple next year. Unfortunately, I'm burning about 10 gals a day of diesel until then.

    I've hit a roadblock, though. Was trying to reply to these posts last nite, but my head was splitting so bad i can't concrentrate. My filling came out and the tooth is unsavable. So instead of digging a trench tomorrow, I'll be doped up and having a tooth removed. Vicoden goes great with backhoes, right? haha.

    Goose, I got 4 different conduit lines I'm running. 1 dedicated conduit for 10gauge electric wire - unknown use yet, 1 dedicated to be empty, 1 for network cable, 1 for tstat/pump wiring. I think I'll go to lowes or home depot and get some tstat wire, hate to waste good cat5 cable, probably double or triple the cost. Definately will keep the electric conduit away from the data cables.
  16. pybyr

    pybyr Minister of Fire

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    Nofossil has previously pointed out, and I agree, that black polyethylene water pipe makes an excellent low cost conduit for underground wiring.
  17. RowCropRenegade

    RowCropRenegade Feeling the Heat

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    That is an excellent idea. Too bad I bought all the conduit I needed 3 months ago. :(
  18. deerhntr

    deerhntr Member

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    I didn't mean for you to redo your existing boiler control wiring, I was just suggesting that you take a look at what you have, and use that as a baseline.

    As for the primary and secondary pump switching, you will still need at least a zone controller for your secondary loads, and a single SR-501 type relay for your primary pump switched off the end switch of your zone control board. Then of course you will need thermostats at you loads that are routed back to the zone control board. It will be cheaper to buy a multizone board, then to do it with individual SR-501, or equivalent. Most of Taco's have expansion slots for add-ons like your "outdoor reset" control.

    Good Luck with that Tooth! ouch :snake:
  19. RowCropRenegade

    RowCropRenegade Feeling the Heat

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    Russ,

    I've been looking at NoFossil's controller for quite a while. It would be a very cool, flexible tool I can grow with. I need to be careful in what I purchase now, considering the barn project will start this summer. I probably won't put in any relays this year. Just let the pumps run on low. It isn't that far to spring. Need to get her up and running so I can go harvest a 150 year old black locust. :eek: Still trying to decide on what pump/zone valves I need inside the house. I've been reading alot about zone valves. Might be cheaper to go with small circulators instead. But tomorrow I'll put in the infrastructure I need to communicate with every building.

    That tooth is gone! I have regained my ability to concentrate. Though vicodin makes me itchy and sleepy. I got an operator for the backhoe, ill be probe/diggerman. Will feel like summer, 44 tomorrow.
  20. sbleiweiss

    sbleiweiss New Member

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    Reed,
    I think you will find that cat5 cable is cheaper per foot than thermostat wire, however I don't think it meets code to use cat5 in place of thermostat wire. The relays and zone valves should be wired with 18 gauge solid core thermostat wire. Even though they carry little current, I think this is required. Get the 3 conductor thermostat wire, that extra conductor can come in handy at times.

    Cat5 is excellent for extending temperature sensors. It is twisted pair which makes it pretty immune to noise. I am sure you will want a thermometer in the house that will show you what the temperature is out at the Garn.

    I am wondering why you are pursuing a primary / secondary piping scheme for this install. I would think that the Garn can handle any amount of water moving through it with little restriction. If this is the case, then you can have multiple pumps in parallel pulling heat out of it and they won't interfere with each-other. I am no expert in hydronics, but I do know that keeping it simple is usually better. I am curios if there is some other reason that pri/sec is needed?

    With regards to relays and controls. You need to add at least minimal control to the system with the initial install. Currently your oil boiler is cycled on and off to regulate the heat in the house. The Garn will not do that, it will just heat constantly. You will loose 5 lbs per night while you sleep. The relays are only $50 and pretty simple to wire up.
  21. RowCropRenegade

    RowCropRenegade Feeling the Heat

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    Scott,

    I went with primary secondary because of the simplicity of tying new systems into it. Originally I was going to pipe it straight to the house then jump out of there to the next point. There just isnt the room to do that in current oil boiler room. The big barn could need as much as 150,000 btus. Which is a number I can't pinpoint until I install insulation and such.

    I called the plumbing store, they carry 18-2, 18-5 thermostat wire. .09 versus .19. I'm planning on keeping the CAT5 cable as for internet/camera use only. Bumping up from 2 to 3 lines of it. One to supply house to barn connection. I probably should run 3 or 4 maybe 5 of tstat wire. 3 different thermstats inside the house, maybe more with addition of radiant systems plus current oil boiler tstat.

    You are right about the controls but I can't make that decision until I know what I'm doing in the house.
  22. deerhntr

    deerhntr Member

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    Reed,
    That is your call. But...... circulating your H2O, when there is no call for heat, will do nothing but over heat your load when the demand is not there, i.e. your house. If you design you system to meet the demand of your design day, that means even on a "low"(i'm guessing a 3 speed grundfos), you still will be pumping way more BTUs than required, and that will mean.....open the windows, it's gettin hot in here.

    As far as NoFossil's controller, you may want to check to be sure, but I think he does not really like switching high voltages in his box. I am not 100% certain, but I think he likes to switch low voltage with the relays in his box. For instance, if you want to do some unique control with your thermostat, you would route the thermostat signal to his controller, process that signal, then use the result to switch 24 volts, or dry contacts on a relay, and send THAT result to a zone controller(low voltage input) to finally switch the 120 volts that turn on/off the circulator. So really you can't get away from a relay to switch your high voltage, unless the circulator is designed with a "heat request" input that is, let's say 24 volts. Then the relay is in the pump!

    Have at it. It's fun.....
  23. Gooserider

    Gooserider Mod Emeritus

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    A couple comments in terms of cabling -

    1. Wire is relatively cheap...

    2. It is no harder to pull several wires at once than it is to pull one... Moral of story, it never hurts to pull extra pairs...

    3. Leave pull strings behind, it makes future expansion FAR easier... What I always do is put in a string about twice as long as the run, plus 4-5', and tie each end to a solid object at the end of the run. Then I fasten the wire bundle to the middle, and use the string as a "shuttle". I just bundle up the extra and leave it stuffed in the box or wall cavity... For the string itself, I use the nylon "masons twine" - low cost, easy to work with, and more than strong enough for the job.

    Gooserider
  24. RowCropRenegade

    RowCropRenegade Feeling the Heat

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    How about going to lunch for 5 mins and the backhoe operator decides against my orders to continue digging. Guess what he hit. My fuel oil line. 3/8 copper line, totally stretched out and screwed. Never been so upset in my life. Fired him on the spot. I finished the digging, vicodin and all. Tomorrow I'll run my new fuel oil line and get the boiler back going. Thank god its not going to be cold out tonite. Pissed til tomorrow.
  25. heaterman

    heaterman Minister of Fire

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    Reed............man this is making my head spin. But here's a couple quick comments after skimming over the whole thread. Some of these were probably covered already.

    In one of the pictures you have what looks like a valve with no handle, it's a circuit setting valve. Made to be adjusted to provide equal flow in two circuits that due to piping differences, don't naturally flow the same. A balancing valve if you will.

    You absolutely do not need a mix valve to protect the Garn from low return temps. About the only way you could thermal shock a Garn would be to return liquid nitrogen to it.

    As I recall you are going to have some heating loads connected in the Garn Barn as well as piping to the house? IE: loads in two different places? If so, where are you going to locate the HX? My choice would be right near the garn and then build a "manifold" that would serve both locations. Having everything from the HX to the loads pressurized would allow you to locate your loop circs anywhere you wanted without fear of low NPSH problems. Piping that way would allow you to leave your current system and control setup basically intact, if you wanted to.

    Just a few late night thoughts.............. give me a ring if you want. I should be around the house tomorrow as we are babysitting 5 grandkids all day. On second thought, that might mean I'm more busy than if was swinging wrenches :)
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