Outdoor Wood Furnace Info
All-Purpose OWF Discussions => Plumbing => Topic started by: tawilson1152 on February 23, 2013, 12:55:36 PM
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I just put an Alpha 15-55 in my supply line from my owb. It's reading 5 gpm at the highest speed. Anyone know how accurate that is? I'm using it to figure the head pressure using the pump curve and wonder if that's right. If so, I can see why the 007 I had on there seemed a little undersized.
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I just put an Alpha 15-55 in my supply line from my owb. It's reading 5 gpm at the highest speed. Anyone know how accurate that is? I'm using it to figure the head pressure using the pump curve and wonder if that's right. If so, I can see why the 007 I had on there seemed a little undersized.
Yea they are supposed to be really accurate, just make sure you leave it on high. If you turn it down on a auto setting it will run to slow... Even on high your only pulling 40 watts
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Yep, the pump is saying just over 40 watts. I am in the hvac trade(tinknocker) and occasionally get some demo'd stuff, so I tried an Armstrong 1050 1.5B bronze pump I had to replace the 007 I was using. It's like new and a beauty of a pump, and sure did move the water, but a overkill for my app. I thought about getting a vfd to slow it down, but decided to go with the Alpha pump. I'd like to move a little more water for the subzero weather. I think I need to eliminate some 90's in the basement, or maybe go to bigger pipe inside. I've got 1" pex now and. Looks like the worst of this winter is over, so I'll probably leave it for this season.
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How many feet of pipe total do you have in the system? Going by your numbers I came up with about 350' round trip minus restriction from heat exchangers and fittings, etc.
Is that close?
If this is right, you gained about 1 GPM over the 007 pump.
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Probably 140' total. The Alpha pump curve shows 15' of head at 5gpm on the highest setting. I think I put too many nineties in the basement trying to keep it of the way. I had to cross the basement to get to my heat exchanger.
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so only 70' each way? Do you have a 10 plate heat exchanger?
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No, it's another demo score. 40 plate with 2" connections.
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Then you should be getting a lot more than 5 gpm.
Any chance the plate is partially plugged?
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I thought I'd get more flow too. I don't think the hx has any restrictions. I checked it before installing and it was clean. When swapping out pumps I ran some water through it and it seemed ok too. I think it's the nineties in the basement that are causing the lower flow. I had lots of flow when I put the Armstrong 1050B 1.5B in. Then I checked what it was costing/month to run. I also think it would wear my pipe out. If I'm reading the pump curve right, it was doing 50gpm+- at the 15' of head I think I have.
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There is no way you will get 50 gpm through 1" pex.
The head pressure is directly related to flow rate. If you increase the flow the head rises fast. For instance, the 007 would move about 4 gpm at about 8' of head and the alpha 5 gpm at 13' of head.
Each elbow is equivalent to about 10' of pex and coupling about 2-1/2 feet.
Is everything in your system 1" pex? How many elbow and other fittings do you have? how big is the water to air heat exchanger? If is a standard 3-1/2" thick heat exchanger? I would check it am make sure there are a lot of connections to the header pipes on it. I have seen some with only 2 or 3.
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Yeah, I guess in retrospect the 50gpm was bonkers, but it was flowing fast. I've got 7 nineties in the basement, all 1" pex, the hx is a 40 plate with 2" connections. At the boiler I went directly from the 1" pex to 1.25". There are 4-1.25" nineties there, as I made it like a swing joint that I could turn down into the pipe coming out of the ground.
I'm not sure what you mean by connections to the header pipes on the heat exchanger.
Thanks for your time, by the way.
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Ok so is the alpha going to be a higher flow rate that what the boerger 1/3 hp pump i have now i cant find any specs on it.I have around 100 feet of one inch pex prob 10 90's.I need a less power hungry pump.Thanks
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I 1050B I tried for a couple weeks was a 1/3hp pump. It moved a lot more water than the Alpha, but ran at nearly 5 amps, which is why I got the Alpha.
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Yeah, I guess in retrospect the 50gpm was bonkers, but it was flowing fast. I've got 7 nineties in the basement, all 1" pex, the hx is a 40 plate with 2" connections. At the boiler I went directly from the 1" pex to 1.25". There are 4-1.25" nineties there, as I made it like a swing joint that I could turn down into the pipe coming out of the ground.
I'm not sure what you mean by connections to the header pipes on the heat exchanger.
Thanks for your time, by the way.
I was assuming you had a water to air heat exchanger.
Are you getting enough heat with the alpha pump? Calculating 70' of pipe and 10 elbows it should be pumping between 7 and 8 gpm. The plate heat exchanger could be restrictive enough to drop the gpm down to 5. How big is it? Can you post a pic?
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I can't find a pic right now. I can take one later, but as I said it's a 40 plate with 2" connections. It was clean when I hooked it up and I believe it still is, so I don't think that's causing the lower flow. I also have a unit heater for the basement teed off the return line to the owb. I think it's the nineties and tees that are slowing the flow down.
I'm getting enough heat now, but not sure about the sub zero weather. The 007 didn't, the 1050B put plenty of heat in the house. But I also had an unwanted flow issue through my zones when I turned up the flow on my indoor primary loop, which I have since solved, so I think the 5 gpm will keep the house warm in the coldest weather. I would like more flow mainly to promote better circulation through the owb. I'm seeing steam out the vent and I can hear it boiling near the end of it's normal cycle to 180 degrees, and I'm having to put a gallon or two of water in it every week, which didn't happen when I had the bigger 1050B hooked up.
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Is the unit heater in series? How large is it and how much extra pipe did you have to add for it?
What are the dimensions of the 40 plate?
Is there any chance there could be any trapped air anywhere in the system?
I have never tried putting another pump in series with an alpha but it might be worth a try to put in the 007 and see what happens. If you have room, just bolt them together.
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I just put 2 tees in the return line and put a pump in the loop. I did have the pump running all the time and controlled the fan with a tsat, but I've shut the pump off and still get enough flow through the heater to keep it hot. Probably because I put the tees on either side of a 90.
The only place I could have any trapped air would be in the heat exchanger, it's all level or uphill from there to the owb. I've got temperature gauges on all four pipes to the hx, so I could do something there for a vent. Good point, thanks.
I thought about adding another pump. I can always take it out. From what I've read, the more powerful pump should be first.
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Ok, I pulled out the thermometer well and stuck in a boiler drain for a vent. It did have some air in it and after bleeding I gained a gpm to get to 6gpm. Then I stuck a new 007 in front of the Alpha, and it is now bouncing between 7 and 8gpm. Funny thing is, it stays right there no matter where I set the Alpha at. Thank you RSI. I just temp wired it with a lamp cord, I'll do it permanent if I'm leaving it. I'm still debating putting the 007 right at the boiler to get better circulation through it.
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That is really interesting, especially not making a difference where you set the alpha. If you set it to constant head it will run full speed because the pump in front of it will pull the water away and keeping it from building pressure. a Grundfos 15-58 would work even better but since you already have that pump, you might as well use it. Let us know how it keeps working.
If you do want to cut your power usage down a lot, you could run a wire out to the boiler and put a strap on aquastat on the pipe and set it up so the taco only comes on when the boiler is running or there is a big temperature drop. Then you could run at 20 watts or so on the alpha all day and use probably less power overall than the alpha on high was using.
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The gpm on the Alpha seems to vary. Can't figure why. This morning it said 9gpm, still at 43 watts. Last night it was at 6. This is with the 007 still running in front of it.
I've got a leak I'm going fix next weekend. As I've got to drain the boiler to fix it, I'm streamlining the piping in the basement. I figure I can eliminate 5 of the 90's I have now. I'll let the pex do the offsetting to the floor where it enters the basement. Didn't give it much thought when I originally piped it. I'll also flush some water through all parts of the system to make sure I don't have any obstructions.
This is a pic of the piping into the boiler. I am considering crossing the connections to get better flow through the boiler. I can hear boiling water inside the boiler towards the end of it's normal cycle to 180. I would welcome input/experience with that.
No matter what, I'm putting valves on all the ports so I can play with it, maybe even putting a pump right at the boiler to circulate through the boiler only.
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Does the GPM change happen to coincide with boiler temperature or when a lot of heat is being drawn off the water? Hotter water flows better so if it is colder you might see a drop in flow.
Going to opposite corners for the boiler supply and return isn't a bad idea.
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9 gpm is more like I expected when I put in the Alpha and it's stayed there for 12 hours now. I'm wondering if I did have some air in my underground lines that finally worked it's way out. I did do a little burping and flushing last night at the new vent I added at the hx. Didn't hear any air, but who knows.
The boiler manual doesn't say about crossing them. I'll give it a whirl, see what happens.
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Do you still have the taco pump running too? Have you tried turning it off to see how many GPM you lose? It doesn't hurt anything leaving it in there turned off. It will make a little restriction but not that much.
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Yep, it's still there and I've turned it off and on a dozen times in the last week to see, and no matter where the Alpha is at, it loses 1 gpm of flow. Tonight it's at 7, and unplugging the Taco dropped it to 6.
I'm gearing up for my boiler repair and repiping job this weekend. I've played with this now enough to feel confident the nineties I'm eliminating will give me all the flow into the house I need with just the Alpha. I am doing the crossover at the boiler too. If I still hear water boiling during the course of a normal cycle, I'll stick the Taco on the back of the boiler on the 2 open bungs to see what it does.
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I did my repair and repipe project this week. The Alpha pump is stll at 6 GPM, but I'm ok with that now because changing the return piping connection on the owb seems to have made a difference. I used my infrared heat gun and I have consistent temperatures, where before I had stratification and I could hear water boiling during the course of a normal cycle. I just fired it up, so time will tell.
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