Would like opinions on the Grundfos Alpha 1

[loudipierro]

Hello all. I am currently in the process of selecting equipment for a new Combi boiler that I am installing in my home. I am a boiler technician but I work with large industrial steam boilers mainly, and mostly with controls. I am not a hydronic expert. But I have done a lot of residential plumbing and HVAC work. I am either going to go with the Laars FT series (140k BTU) or the Bosch Singular 4000 (155k), both are priced the same and are roughly the same size. I'm actually not sure which one to go with but thats a topic for another thread. If any of you guys have a preference between those two brands please let me know.

However, the reason I created this thread and what I am having a little bit of difficulty with is selecting a circulator. I've taken measurements and done the head loss calculations, but its very close so I'm really not sure. I just wanted to get some opinions on this. Here are the details about my house and heating system:

Home is about 2000 sq ft of heated space, 4 heating zones all with 3/4" zone valves.

Zone 1 is radiant floor in the original concrete slab which is a total of about 850 sq ft. There are 4 loops, each one about the same size and consisting of about 80-100 feet of 1/2" copper tube in the concrete. I am putting in a new 4 loop stainless manifold to supply the 4 loops. The manifold itself is going to be supplied from the zone valve with 1" PEX (supply and return) and is about 40 feet from the zone valve (so 80 feet of 1 PEX total). There will be very few, if any, fittings in the PEX.

Zone 2 is two sections of 3/4" fin tube, each section is about 14 feet long. There is a tee splitting into the two sections and the Tee will be supplied from the zone valve by 1" PEX. Again about 80 feet total of 1" PEX with no fittings.

Zones 3 and 4 are virtually identical - each of them is about 28 feet of 3/4" fin tube supplied from the zone valve with 3/4" copper (less than 10 feet of it in both cases).

Clearly the radiant floor represents the largest head loss here, from my calculations about 7 or 8 feet of head total (worse case). The pump I would like to get is the Grundfos Alpha 1 but I'd like to get opinions on that and see if you guys think it will be sufficient. If you look at the curve you will see that it probably will not supply quite enough flow for all 4 zones at the same time but my thinking is this: the radiant floor runs for a while to heat up the concrete slab, but once that happens, the zone hardly ever calls for heat. Once the whole slab is warmed up, the zone only calls for a few minutes at a time every once in a while (not very often). When the radiant isn't calling, the fin tube zones will have plenty of flow available with that pump. The reason I want this pump is because it changes its speed to maintain a constant pressure, its very efficient. Neither Grundfos nor Taco make a more powerful pump that is available with the constant pressure control. In order to step up to a pump that I KNOW would be more than enough, I'd have to go with something like the 1/6 HP Grundfos UPS26-99, which I feel is overkill for my house.

 

[breplum]

Do you have a load calculation yet?
I recommend posting on The Wall/Heating Help
And talking to the tech desk at Grundfos...have your GPM

 

[loudipierro]

Do you have a load calculation yet?
I recommend posting on The Wall/Heating Help
And talking to the tech desk at Grundfos...have your GPM

The required heating load for the house is about 80k BTU. I've done several estimates and calculations myself and they all come out to somewhere between 78k and 85k BTU. It definitely isn't more than 85k because the house has all brand new windows and siding, including additional new insulation.

These systems are all existing and were previously split into two separate systems. Zones 1 and 2 were heated by an old cast iron boiler with a Taco 009 circulator while Zones 3 and 4 were heated by a 50 gallon tank HW heater and a Taco 006 circ. With those two circs the zones were probably seeing a total of 16-18 GPM (9-10 GPM for zones 1 and 2; 7-8 for zones 3 and 4).

I don't see the "Wall - Heating Help" section you referred to. But I will try to speak to the tech desk at Grundfos and see what they think. I'm just trying to avoid oversizing the circulator. I know thats a common practice with plumbers to prevent callbacks, but since this is my house, I want something efficient. Like I said, I know the Grundfos UPS26-99 or Taco 0011 would be more than enough and if they made one of those with the constant pressure control, I would buy it without question. But they don't.

The other option that I am considering is using a separate circulator for the radiant floor zone (probably a good old Taco 007) and then a second circ for the fin tube zones with zone valves. But that increases the complexity of the controls, I would probably have to purchase two separate controllers for that (a Taco zone valve controller plus a Taco switching relay). I'm trying to avoid that too.

 

[Bird Doo Head]

If it's not too late, perhaps 4 pumps & flow control (check valves) instead of zone valves & one pump would be more cost efficient now & in the long run. The taco 007 will handle what you described with no problems.


Height (feet of head or static head) is no problem with hydronic because it's a closed loop.
Restriction (friction head) is the challenge, but your description does not reveal any very restrictive zones.
Both Taco & Grundfoss have calculators & curve charts on line. Either will select for you if you send a detailed drawing. Include what delta temperature you will prefer.



You asked about Laars & Bosch:
I've no experience with the Laars FT other than seeing them at trade displays. They look well designed and very easy to service.
I do have experience with other Laars:
Starting when the hybrid heat exchanger models were first introduced, I installed dozens of small 199,999 btu Teledyne Laars Minitherm at work for indirect water heating (with Amtrol BoilerMates or similar). The boilers were often piped parallel, in banks of two to eight per BoilerMate parallel group.

The boilers ran almost 24/7 & the heat exchangers only failed (at the rolls) if dry fired. (Penny foolish bosses didn't approve of low water cutouts)

I also put a few smaller Laars boilers in friends' homes (with low water cutouts). No complaints yet.

Laars was always very good about warranty. Units & parts are made in USA and parts were always in stock locally. Many are generic parts, too. They often offer rebates, as do some utility companies. (Maybe IRS, too)

What Breplum mentioned is: Heating Help #1 Online Resource for Heating Answers
Click on "The Wall" in the top row to get to the forum.

I hope this is helpful!

Paul

 

[Arctic trouble]

The grundfos pumps are nice for sure I got a smaller magna series unit for somewhere around $500 last year. I also was considering a taco that had wifi so you can fine tune the adjustments. If you want to be efficient then I would just recommend rethinking the condensing boiler with fin tube. Condensing boilers are most efficient at lower temperatures which works well for your floor heat.
Slant fin or fin tube requires higher temperatures so people end up cranking up the boiler temperature to get heat out of the fin which defeats the purpose of the condensing feature of the boiler.

 

[breplum]

https://forum.heatinghelp.com/

 

[loudipierro]

If it's not too late, perhaps 4 pumps & flow control (check valves) instead of zone valves & one pump would be more cost efficient now & in the long run. The taco 007 will handle what you described with no problems.


Height (feet of head or static head) is no problem with hydronic because it's a closed loop.
Restriction (friction head) is the challenge, but your description does not reveal any very restrictive zones.
Both Taco & Grundfoss have calculators & curve charts on line. Either will select for you if you send a detailed drawing. Include what delta temperature you will prefer.



You asked about Laars & Bosch:
I've no experience with the Laars FT other than seeing them at trade displays. They look well designed and very easy to service.
I do have experience with other Laars:
Starting when the hybrid heat exchanger models were first introduced, I installed dozens of small 199,999 btu Teledyne Laars Minitherm at work for indirect water heating (with Amtrol BoilerMates or similar). The boilers were often piped parallel, in banks of two to eight per BoilerMate parallel group.

The boilers ran almost 24/7 & the heat exchangers only failed (at the rolls) if dry fired. (Penny foolish bosses didn't approve of low water cutouts)

I also put a few smaller Laars boilers in friends' homes (with low water cutouts). No complaints yet.

Laars was always very good about warranty. Units & parts are made in USA and parts were always in stock locally. Many are generic parts, too. They often offer rebates, as do some utility companies. (Maybe IRS, too)

What Breplum mentioned is: Heating Help #1 Online Resource for Heating Answers
Click on "The Wall" in the top row to get to the forum.

I hope this is helpful!

Paul

Thank you for this info. I have had several people suggest to just zone with circ pumps, and I think I might just do that. Get four 007e and call it a day. They even have integral check valves so no need to buy those. The total cost won't actually go up that much considering the size of pump I would probably need for all four zones. Also, thanks for the info about the Laars. I actually just had a Laars minitherm, it was installed in my house in 1986 and has been used 5 or 6 months every year for the last 37 years. There was actually nothing wrong with it when I pulled it out last month, but since my hot water heater was also starting to go bad (its 12 years old) I decided to install a combi. I was leaning towards the Laars anyway, now I'm going to stick with them.

 

[Bird Doo Head]

Arctic Trouble's reply made me realize that I forgot to mention an important item:
If a boiler's water temperature is set high enough for rated BTU output for fin tube or cast iron baseboard or radiator (typically 160-F @ 1 gpm), the floor will be very uncomfortable. Some floors will be damaged (hardwood is one).

Work Around:
Sometimes a single boiler is set for the temperature needed for the fin tube and the system will include a tempering valve & pump to mix return water into the in-floor zone so the floor is not uncomfortable. But, as Arctic Trouble mentioned, much benefit from a condensing boiler's low temp option is lost at the 160-F setting.

Another idea, if it's not too late:
Skip the fin tube and use flat panel radiators. They are very capable of generous BTU at the low water temperatures in-floor needs. They work well with towel warmers, too.

A benefit is that they heat by both radiation (like a radiator) and convection (like a fin tube baseboard). Another is local control at each unit. The downside is the residual heat is is short term, unlike that of cast iron radiator or cast iron baseboard.

Buderus is a good flat panel. Eco Style is made by Biasi & is good. Myson's good, as is Runtal. I don't like the Beacon Morris (Brugmann in disguise) because warranty claims are 100% impossible.

For Fun, search "Feature Radiator" for some jazzy looking low temp radiators. Springs, triangles, waterfalls, square tubes, zig zags, all kinds of crazy designs... Even one that looks like a clothes hanger.

 

[Bird Doo Head]

I actually just had a Laars minitherm, it was installed in my house in 1986 and has been used 5 or 6 months every year for the last 37 years. There was actually nothing wrong with it when I pulled it out last month, but since my hot water heater was also starting to go bad (its 12 years old) I decided to install a combi. I was leaning towards the Laars anyway, now I'm going to stick with them.

Thanks for the report on your experience with the Minitherm. Glad it worked out. They are workhorses.

There's a good used market for these Minitherm if you're inclined to sell on Craigslist, eBay or Bonanza. People like them for indirect hot water & snow melt when they have forced air furnaces.

 

[Arctic trouble]

The Toyotomi HC 190 or 22's are nice units that work well with temp inputs as low as 110°. My opinion is if you spend the extra money for a condensing unit then everything in your system should be low temp capable like 130° or less. One 007e would be more than capable of handling all of that. 1 Zvc controller, 1 pump, 4 zone valves that's what I would do. Clean, efficient, compact and easy to maintain. Not trying to start a pump to zone war just stating what I would do.

 

[loudipierro]

Guys, I appreciate all the suggestions but everything in the house is already existing, I'm not changing anything in the rooms. All the fin tube is already there and I don't have the budget to be changing out the entire heating system in the house. When the copper tube in my slab starts leaking (its only a matter of time) I'll have to abandon it and install new units downstairs and I will keep your suggestions in mind, I particularly like the idea of flat panel rads. But right now this is just a boiler and water heater change. So if you don't think I should go with a condensing boiler, than what? The Laars FT unit I have in my cart on Supplyhouse is only $2300 and its more than enough to heat my house and supply hot water. I'm not sure I could get anything cheaper, condensing or otherwise. FYI the Laars includes an OAT sensor for reset, which I plan to use. The fin tube in my house will provide enough heat with water as low as about 140 or 150, as long as it isn't too cold out (I've done it before manually with my old boiler). But I do have to have 180F water when its really cold.

The Toyotomi HC 190 or 22's are nice units that work well with temp inputs as low as 110°. My opinion is if you spend the extra money for a condensing unit then everything in your system should be low temp capable like 130° or less. One 007e would be more than capable of handling all of that. 1 Zvc controller, 1 pump, 4 zone valves that's what I would do. Clean, efficient, compact and easy to maintain. Not trying to start a pump to zone war just stating what I would do.

Are you saying you think a 007 would be enough for my WHOLE HOUSE (all four zones) as they exist now??? I have to say I disagree with that based on the measurements and calculations I've done. But if you really think it is, than the Grundfos Alpha1 would definitely be enough.

Arctic Trouble's reply made me realize that I forgot to mention an important item:
If a boiler's water temperature is set high enough for rated BTU output for fin tube or cast iron baseboard or radiator (typically 160-F @ 1 gpm), the floor will be very uncomfortable. Some floors will be damaged (hardwood is one).

The radiant floor is original to my house (1965) - it is actually 1/2" copper tube in the concrete slab (and its a good 2 inches under the surface of the concrete). The copper is not coiled back and forth like a modern PEX radiant, in fact the routing of the copper is more like fin tube (runs mainly around the outside perimeter of the house), there isn't much tube inside. So you can't compare this floor to a modern PEX floor which would have hundreds of feet of PEX spaced close together. My floor is very different. There was never mixing in this house. HOWEVER, I added a 4-way mixing valve several years ago with the old boiler and was able to get slightly better control with the valve set at about 80 or 90%, but thats it. What actually works better is outside air reset, and with the new boiler I will finally have an automatic OA reset. Once I have that, I won't need mixing for my floor. It is designed to run at the same temps as the fin tube. The only time I ever have an issue with the floor is if I am running 180F water through it in the fall or spring when its cold at night and over 50F during the day. On those days the house would overheat because the entire slab would be warm and stay warm well into the day. This isn't really a problem with OA reset, however, and I also have a whole house ducted heat pump that I typically run from April to November. So the HW heating is really only for Dec - March anyway.

 

[Arctic trouble]

A large percentage of installs in my area are oil fired cast iron. and a very common system pump for a number of them is a 007. 1 pump and multiple zone valves is the norm. That may or may not be what would work for you, mod con is very different animal. I would suggest you do more research before pulling the trigger. The other forum as suggested is a great place to start. I just hate to see people spend the money on the latest and supposedly greatest and then it not work as efficiently or as reliably as they hoped.

 

[loudipierro]

Can you give me an idea of about how much piping you have seen a 007 handle on its own? Or at least what size home by square footage? I'm just trying to get an idea. The Grundfos Alpha 1 is a bit more powerful than a 007 and I have a strong feeling that it will probably be enough for my house. In fact I think it is probably the correct circulator for my home (not oversized or undersized). But I would hate to find out this winter on a 0 degree night that it can't quite move enough water to keep my house warm. It wouldn't be a disaster because one of my zones is a garage that I can dial back to 50 degrees and it wouldn't matter, but still. I would end up having to get a larger pump which would mean piping changes, because anything larger is also larger flange to flange.

 

[Bird Doo Head]

Can you give me an idea of about how much piping you have seen a 007 handle on its own? Or at least what size home by square footage? I'm just trying to get an idea.

It's kind of hard to compare by pipe-feet or square footage. Pipe size, elbows, venturi tees, monoflo tees, balancing valves all come into play. Also, series loop, two-pipe, etc. Even type of radiation & how it's fed matter.

For a big, wide ballpark comparison:
Several years ago, I installed a 007 in an old, moderately insulated 2200 Ft Sq house near the tip of Michigan's Keweenaw peninsula. The land juts out into Lake Superior. In January & February, it's just plain cold & very windy at night. No complaints about the pump & at last check it's still operating.

The system is on two stories with 3 zone valve zones and one zone is two-pipe reverse return. Some units are fed with venturi tees. Balancing valves are on all radiation units, some remain partially closed. Main = 3/4" copper. Branches = 1/2" copper. Radiation is a mix of 1/2" copper fin tube baseboard, cast iron radiators & two fan coil units. I apologize but I do not remember the gallons-per-minute at testing.

If you're not sure, go with a larger pump that is GPM adjustable. Remember sometimes too much flow is detrimental to BTU output.
I hope this helps a bit.

 

[Arctic trouble]

2400 +garage so 3000ish

 

[loudipierro]

It's kind of hard to compare by pipe-feet or square footage. Pipe size, elbows, venturi tees, monoflo tees, balancing valves all come into play. Also, series loop, two-pipe, etc. Even type of radiation & how it's fed matter.

For a big, wide ballpark comparison:
Several years ago, I installed a 007 in an old, moderately insulated 2200 Ft Sq house near the tip of Michigan's Keweenaw peninsula. The land juts out into Lake Superior. In January & February, it's just plain cold & very windy at night. No complaints about the pump & at last check it's still operating.

The system is on two stories with 3 zone valve zones and one zone is two-pipe reverse return. Some units are fed with venturi tees. Balancing valves are on all radiation units, some remain partially closed. Main = 3/4" copper. Branches = 1/2" copper. Radiation is a mix of 1/2" copper fin tube baseboard, cast iron radiators & two fan coil units. I apologize but I do not remember the gallons-per-minute at testing.

If you're not sure, go with a larger pump that is GPM adjustable. Remember sometimes too much flow is detrimental to BTU output.
I hope this helps a bit.

Thank you! This is really all I needed to hear from someone. My house, not including the garage, is less than 2000 sq ft, with the garage its about 2000 sq ft, but not more. There are also going to be very few fittings between the zone valves and fin tube/floor. There is no question in my mind now that the Alpha1 will be enough pump, probably more than enough. It would be a waste of money for me to put in 007s for every zone, totally unnecessary. I'm going to go with my original plan - zone with Honeywells and a single Grundfos Alpha1.

 

[loudipierro]

I'm actually going to take your guys suggestions and install additional fin tube upstairs in my house as part of this new boiler project. I found out the other day that the other fin tube zones in my house are already significantly oversized and will heat the spaces even with relatively cool water (about 140, maybe even less). This is because those zones were previously being heated by a tank hot water heater, not a boiler. So the upstairs fin tube zone in my house is the only zone that I actually need 180 degree water, if I add another 12 feet of fin tube to those two bedrooms upstairs, I'll be able to run the new boiler much cooler and still heat the house. I probably won't ever have to go over 160.

 

[loudipierro]

This weekend I got my new combi installed. As you can see I only piped the primary side so we have it for domestic hot water and I'm going to be working on the secondary side throughout the summer. Take a look at the pics, if you guys have any suggestions let me know. As I stated in the start of this thread I'm not a pro plumber so there may be some tricks I'm not aware of. Also, if you guys have a recommendation of the best way to purge this out with the arrangement I put in, please speak up. Its already full and operating, but I think there is still a little bit of air in the primary side. After I get the secondary side done I want to do a full purge of the whole system (which I may or may not do myself, I'm not sure yet). FYI I still have some odds and ends to take care of (like piping the relief valves down to the floor and I'm probably going to pipe the intake to the outside with PVC).

 

[havasu]

A very nice install. I like your gas drip leg!

 

[loudipierro]

A very nice install. I like your gas drip leg!

Thank you! At this point the only mistake I think I made was using those iron unions at the boiler. Those were a ***** to tighten down and I know after a few years they will virtually impossible to take off if I ever need to. I absolutely should have spent the extra money and used brass. The only reason I used them was because I got them for free and 1 1/4" unions are about 30 bucks. I'm going to put some tape and anti seize on the threads, hopefully that will help.