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[tawilson1152]

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.

[Scott7m]

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

[tawilson1152]

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.

[RSI]

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.

[tawilson1152]

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.

[RSI]

so only 70' each way? Do you have a 10 plate heat exchanger?

[tawilson1152]

No, it's another demo score. 40 plate with 2" connections.

[RSI]

Then you should be getting a lot more than 5 gpm.
Any chance the plate is partially plugged?

[tawilson1152]

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. 

[RSI]

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.

[tawilson1152]

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.

[Drivebymashing]

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

[tawilson1152]

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.

[RSI]

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?

[tawilson1152]

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.