Grundfos Alpha

[huffdawg]

Does anyone use a Grundfos Alpa ? Im thinking about installing one on the bridge supplying my primary loop,and also one on the bridge supplying my Gas Boiler heating system from the primary loop. What gives the Alpha the signal to speed up or slow down . Does it stop circulating completely when there is no demand? Also I've looked at the drawings of it and I cant figure out what size the inlets and outlets are, I am assuming you can use it on 1" and 1-1/4" pipe.

Huff

 

[in hot water]

I have a few running on my system. I have used them in radiant and solar applications and on my wood boiler. You size it as you would any other circulator. It uses the same flanges or iso flanges as any other circulator, up to 1-1/2" size.

In a nutshell this is how they operate, and the link below explains how they work in a piping system.

The Alpha is a Delta P or a "pressure differential" circ. If you have a one zone, constant flow needs, all the Alpha would offer is reduced energy consumption, the Delta P function would not be used.

Some times a regular circ with a variable speed control is a good means to shuffle heat around. Picture 20 is my system a week ago, all 3 circs were on variable speed control, Their speed ramps up as the temperature differential increases.

Today I have a separator tank that eliminates one pump. Every pump in the drawing runs on a variable speed function including the drainback circ.


www.pmengineer.com/Articles/Cover_Story/BNP_GUID_9-5-2006_A_10000000000000187323

 

[huffdawg]

Thanx for the help IHW. Here is the design summary for my house it says total flow 4.9 USGPM . the grundfos alpha as far as I can tell only comes in one size the 15-55 and the specs. say it can circulate 19USGPM . It seems to me that the alpha would be more than effecient. Am I right .

 

[in hot water]

Your design calls for 4.9 gpm at 10 ft. head. The Alpha fits that spec nicely.

If the loops are individually zoned use the Auto Adapt setting. Red or Black settings if it is all one zone.

hr

 

[huffdawg]

Your design calls for 4.9 gpm at 10 ft. head. The Alpha fits that spec nicely.

If the loops are individually zoned use the Auto Adapt setting. Red or Black settings if it is all one zone.

hr

I have 2 manifolds 1 with 5 loops and 1 with 2 loops, the 2 manifolds have zone valves before them .Also there is 1 loop for the bathroom on a zone valve and 300' loop for the slab in the garage that is on a zone valve. This is all low temp served by 1 GF pump

There are 2 loops for the high temp baseboard each one has its own zone valve. served by one grundfoss pump.

I guess you wouldnt count the dhw as it is priority and only comes on by itself. The alpha would be supplying all of this with heat from a primary loop which will be getting served from another alpha on a bridge from the boiler circ.

Huff

 

[in hot water]

It would be excellent for those zoned manifolds. this is exactly what it was designed to do, adjust it's output bases on the changing load.

What type of DHW indirect tank do you have? Some have small diameter HX coils and are happier with a high head circ, if you want the best recovery and performance. If so the Alpha would work, but a bit slower recovery with less gpm in high head operations.

Slide up the left hand axis to the feet of head, read across to the pump curve line then down to the bottom to see the flow you will get at different pressure drops.

You want to run in the mid 3rd of the pump curve not at the top or bottom end.

hr

 

[huffdawg]

Its a Buderus LT 200 the pump that is serving it is a grundfoss ups 26-99. looks like the flowrate is 17.6 GPM . I think it would be in the high end of the alphas curb.

Horizontal Models LT-160 LT-200 LT-300
Performance Data
Continuous Rating (2nd Hr.) BTU/Hr. 93,000 109,000 161,000
Inlet Temp. = 50ËšF Outlet Temp. = 140ËšF Gallons/Hr.3 124 145 215
Boiler Water Temp. ËšF 194 194 194
Boiler Water Flow Rate (GPM) 15.4 17.6 22.1
Coil Pressure Drop (Feet of Head) 3.1 4.4 8.0
Physical Dimensions
Contents (gallons) 42 53 79
Dimension W 25¾“ 25¾“ 25¾“
Dimension H1 25¾“ 25¾“ 25¾“
Dimension L 36¼†427∕16 57¾â€
Weight (approx. lbs.)2 220 246 363

 

[in hot water]

As you see that Buderus tank has a large diameter low pressure drop coil. The Alpha will pump it but not as much GPM as the 26-99 will. I suspect it will work fine unless you have a huge, continuous DHW demand or you want fast recovery on the tanks.

hr

 

[huffdawg]

As you see that Buderus tank has a large diameter low pressure drop coil. The Alpha will pump it but not as much GPM as the 26-99 will. I suspect it will work fine unless you have a huge, continuous DHW demand or you want fast recovery on the tanks.

hr

As I will be sending heated water through my gas boiler from the alpha which will be on the bridge to the primary loop. Will the 26-99 pull through the alpha , and if so will it be a problem.

 

[muleman51]

I have some interest in a Alpha pump. Last weekend the supply pump to the house decided to start leaking. The water was coming out through the motor, out the top of the junction box on top. It was a B&G SLC-25 4 speed pump, I ran it most of the time on the third setting. The pump I found on Sunday morning was a Grundfos UF15-18SF, my brother inlaw had it sitting around. It doesn't seem to move as much water asto other pump. My question is, is an Alpha pump worth the money as they are $260 as opposed to $65 for single speed pump or not much more fo a 3 speed. I have three zones in my system. will The pump save enough to justify the extra $$. Some of my zones are off probably 50-70% of the time. Thanks for your help. PS the Adobe is limping along as long as you don't expect too much.

 

[in hot water]

Yeah, that 15-18 was typically for DHW recirc lines not quite the pump the B&G you had.

Here is a chart that Wilo developed to show the cost of operation, based on the system data and conditions they show below. Your milage may vary

This Wilo is a close competitor to the Alpha. Shop around I've seen that Alpha around the $240.00 range online. Maybe price the Wilo also. B&G should have their version out soon, I believe it will be an ECM motor without all the delta P functions, I'll bet is hits the market a lot less $$ without all the electronics onboard.

hr

 

[pybyr]

Taco has an ECM circulator due out, also. They had a naming contest for it last Spring, and I am surprised that the product has not (as far as I know) reached distribution yet.

 

[huffdawg]

From what I have read,it doesnt seem like the alpha pump would be a good choice for a primary loop circulator! Am I correct?

 

[in hot water]

[quote author="huffdawg" date="1294478695"]From what I have read,it doesnt seem like the alpha pump would be a good choice for a primary loop circulator! Am I correct?

If you just need a fixed speed circ it is a bit overkill. The advantage of the Alpha is it's ability to modulate speed based on delta P (pressure difference). With a bunch of zone valves, for example, it can modulate it's speed (output) as the various valves open and close. So every zone(s) gets the exact amount of flow required.

In your case operating at a fixed speed you will still see the 40- 50% reduction in power consumption. The ECM is a high efficiency motor, so it will move the same amount of flow, as a 15-58 for example using about 1/2 the electricity. The more electricity rates increase the more you save

Sort of like buying a hybrid car, when does the fuel savings start to pencil out? Sales of those may increase if we see the 5 bucks a gallon gas some predict.

hr

 

[huffdawg]

From what I have read,it doesnt seem like the alpha pump would be a good choice for a primary loop circulator! Am I correct?

If you just need a fixed speed circ it is a bit overkill. The advantage of the Alpha is it's ability to modulate speed based on delta P (pressure difference). With a bunch of zone valves, for example, it can modulate it's speed (output) as the various valves open and close. So every zone(s) gets the exact amount of flow required.

In your case operating at a fixed speed you will still see the 40- 50% reduction in power consumption. The ECM is a high efficiency motor, so it will move the same amount of flow, as a 15-58 for example using about 1/2 the electricity. The more electricity rates increase the more you save

Sort of like buying a hybrid car, when does the fuel savings start to pencil out? Sales of those may increase if we see the 5 bucks a gallon gas some predict.

hr

I have 2 alphas I was thinking of swapping one out with the 15-58 3 speed that supplies my low temp loads . There are 4 zone valves after that pump . The pump only comes on when there is a demand for heat . So I think it would be a bit of a toss up of which location it would save me the most $$ as the primary loop runs all time.

What about having an Alpha as a boiler circ pump .