Grundfos Alpha circulator 2 boiler system

Unknown

I am trying to find out how the Alpha pump works, and whether it can be used on a two boiler hot water system (zone valves and/or circulators).

As I understand it, the pump plugs into an outlet, and not the boiler relay.  The pump, while idle, uses 5 watts, and turns at very low rpms.  It will increase its speed when it detects the change in pressure or suction when a valve opens.  It increases its speed if more valves open.

If I have that correct, and you have two boilers, 3 zone valves and a pump on each boiler, I see the following happening.  With a boiler control, boiler one receives a demand for heat, and the Alpha would start pumping with the opening of a valve.  If boiler two received NO call for heat, its pump (if, an Alpha) would still come on (not good).  Am I correct in my assumptions?

And, if one used a traditional Grundfos pump, such as their UP 15-10F on the second boiler (with no boiler rotation), this is where I get fuzzy.  This second pump closely matches the optimum flow through its boiler, but will the Alpha on boiler one respond as if it were on a one boiler system?  Or am I whistling Dixie?Any thoughts?

Dave Yates (GrandPAH)

no need

You can run the Alpha like that if you want the simplicity and don't mind wasting 5-watts of power. But, if you're adding one to save power, why not treat it like you would any other circ and let your ZV's end switch trigger a relay to only energize the circ like you would any circ.

Mark Eatherton

How are the boilers piped?

in parallel or as secondaries to a primary, or how?



Also, what KIND of boilers, modcons, atmospherics, near condensors?



ME

Paul Pollets

Plug

the pump plugs into an outlet, but you can easily add the outlet box at the pump relay for a specific zone.



The pump has several configurations and will work for most applications as you describe.

Unknown

Grundfos Alpha circulator 2 boiler system

I am an old coot, and don't have much use for these head-aches called high-efficiencies.  I would like to use two Weil Mclain CGa-3 cast iron boilers (about 50,000 IBR rating) with standing pilot in a primary with a secondary using a hydraulic separator.  Dave, the front part of the home was probably an old gravity conversion (age: 1930) system which worked well with a B&G series 100 pump that has a relatively flat curve needed for the higher head and flow. There is 70 gallons in this part of the system.

Mark, I was thinking of using circulators for zoning because of the disparity of the above zone requirement, versus the back two zones where the head is less than 3, and a low flow (60 feet of copper-fin tubing about equal in two zones).  See attachment for nearby piping that I am considering.

Paul, I have since heard from Grundfos, and I now know the pump can be put in an outlet fed by the relay.  Grundfos also told me, by "early next year," the relay can be wired right to the ALPHA.

Right now, I am wondering if I should even be considering the nearby system attached.  I could use two of the Grundfos UP 15-10F circulators on the boilers, and an ALPHA on the secondary with valves (different than drawing), but I worry about getting enough head and flow to the large zone.  If I use the attached drawing, I could also put four of the UP 15s on the two boilers and two small zones.  The circulator that seems to be the closest match to the series 100 B&G is a Taco 005 or 007.  If I used a variable speed, I could set the Delta T that seems to work the best. 

The one thing that still bothers me with the attached system drawing, however, is warm weather.  If only one boiler gets the call, the pump flow off the boiler is only 5-6 GPM, and if all three zones are open, I could see where the return might be 7-8 GPM or more. This would put 3GPM or more thru the separator and back into the secondary.  60% return water back into the secondary.  This doesn't sound like good design to me.

I live in the Chicago area, and paid $1850 for nat. gas.  I was hoping to improve that using two boilers.  Burnham just came out with their ES2 boiler (low volume cast iron) which, they say, can take return water temperatures down to about 100f.  They have a card that fits the boiler panel that will do an outdoor reset, but the technician said something I didn't like.  An 80% boiler has a 20 year life (ES2 is 85% and qualifies for tax credit).  Now, I know Burnham is a great name, but I have had a number of Weil Mclains, and they are still going.  One of them was ready for Medicare, just like me.  As far a pumps go, whether you use one pump or 5, they don't have to change the cost a whole lot.  If I used all Taco pumps, I am using 230-250 watts.  While it doesn't change my overall cost a lot, I would rather use less electric.  The four UP 15-10F pumps use a total of 100 watts (25 watts each).  The Taco 005 was about 50 watts and the 007 was over 70 watts.  The ALPHA range is 5-45 watts.  If I can get the watts to 150, I am as happy as a pig in a 4" deep pond.  I want performance and comfort, a low gas bill, and boilers that I can do like Ron Popeil, "set it and forget it."

Thank you for your input thus far,

Any ideas?

Unknown

Grundfos Alpha circulator 2 boiler system

I am an old coot, and don't have much use for these head-aches called high-efficiencies.  I would like to use two Weil Mclain CGa-3 cast iron boilers (about 50,000 IBR rating) with standing pilot in a primary with a secondary using a hydraulic separator.  Dave, the front part of the home was probably an old gravity conversion (age: 1930) system which worked well with a B&G series 100 pump that has a relatively flat curve needed for the higher head and flow. There is 70 gallons in this part of the system.

Mark, I was thinking of using circulators for zoning because of the disparity of the above zone requirement, versus the back two zones where the head is less than 3, and a low flow (60 feet of copper-fin tubing about equal in two zones).  See attachment for nearby piping that I am considering.

Paul, I have since heard from Grundfos, and I now know the pump can be put in an outlet fed by the relay.  Grundfos also told me, by "early next year," the relay can be wired right to the ALPHA.

Right now, I am wondering if I should even be considering the nearby system attached.  I could use two of the Grundfos UP 15-10F circulators on the boilers, and an ALPHA on the secondary with valves (different than drawing), but I worry about getting enough head and flow to the large zone.  If I use the attached drawing, I could also put four of the UP 15s on the two boilers and two small zones.  The circulator that seems to be the closest match to the series 100 B&G is a Taco 005 or 007.  If I used a variable speed, I could set the Delta T that seems to work the best. 

The one thing that still bothers me with the attached system drawing, however, is warm weather.  If only one boiler gets the call, the pump flow off the boiler is only 5-6 GPM, and if all three zones are open, I could see where the return might be 7-8 GPM or more. This would put 3GPM or more thru the separator and back into the secondary.  60% return water back into the secondary.  This doesn't sound like good design to me.

I live in the Chicago area, and paid $1850 for nat. gas.  I was hoping to improve that using two boilers.  Burnham just came out with their ES2 boiler (low volume cast iron) which, they say, can take return water temperatures down to about 100f.  They have a card that fits the boiler panel that will do an outdoor reset, but the technician said something I didn't like.  An 80% boiler has a 20 year life (ES2 is 85% and qualifies for tax credit).  Now, I know Burnham is a great name, but I have had a number of Weil Mclains, and they are still going.  One of them was ready for Medicare, just like me.  As far a pumps go, whether you use one pump or 5, they don't have to change the cost a whole lot.  If I used all Taco pumps, I am using 230-250 watts.  While it doesn't change my overall cost a lot, I would rather use less electric.  The four UP 15-10F pumps use a total of 100 watts (25 watts each).  The Taco 005 was about 50 watts and the 007 was over 70 watts.  The ALPHA range is 5-45 watts.  If I can get the watts to 150, I am as happy as a pig in a 4" deep pond.  I want performance and comfort, a low gas bill, and boilers that I can do like Ron Popeil, "set it and forget it."

Thank you for your input thus far,

Any ideas?

Paul Pollets

Piping and boiler selection

Ii'd be using one condensing wall-hung appliance, rather than 2 cast iron boilers. But that's your decison.... The drawing shown will heat up the 2nd boiler whenever the other boiler is firing. A "reverse-return" method should be used to pipe in 2 boilers.

Mark Eatherton

I'm an old coot too!!!

and I prefer to use the newer mod cons over the near cons and non cons.



It is probably a good thing you are retiring soon, because I forsee that within the next 10 years, you won't be able to purchase anything but the 92 %ers. Such is the case across the pond right now.



If you are dead set on using a lesser product, go with the more efficient VS circulators, at least. And put as much reasonable technology on it as you can in the way of ODR etc.



These new high efficiency products really don't have as many problems as people perceive. Oh sure, they went thru a rough period of time, but that is behind us now, and they are really quite reliable. If there WAS a problem, you can either poll through the memory registry, or hook a lap top computer to it and see EXACTLY what went wrong, and when it went wrong. With conventional technology, you are guessing and a parts replacer until you get it right.



But I understand, if you want to stand your ground...



Happy Retirement



ME