Help me choose a new-fangled circulator pump (or tell me to stick with my 007)

[Bob Rohr]

Answers to a couple questions above.........

Delta T vs Delta P; I guess the simplest way to put it is that in nearly all cases Delta P corresponds to Delta T. If you drop the head (P), which usually corresponds to GPM, the temp differential will also change. The less flow, the more temp differential you can generate.
On a commercial job we removed a 3HP Taco 1900 series pump that was rated 70 GPM @ something around 65-70' of head and replaced it with a WIlo ECM pump that would do 40' head maximum. I knew the zone was severely over pumped because with all the heat emitters on we only saw a temp difference of about 5*. We piped up the Wilo and started dialing it in to achieve a 20* temp drop from supply to return. When we finished the process, everything was getting sufficient flow at a head of only 23' and our temp drop was a nice 18-20*. The Wilo used less than 1/10th of the KW the Taco did.

As others have mentioned some of the Delta T pumps on the market are not true ECM motors. The Wilo and Grundfos are. As such, those pumps are not able to "idle down" to the same level that a true ECM will.
Bottom line recommendation for me in almost every multi zone application is going to ECM.

One other factor that should be considered when the topic of per KW costs are "on the radar" is that about 200 coal fired power plants have been or are in the process of being shut down here in the US. Virtually everyone I have spoken with that works in the power production industry has told me that we can expect a 20-30% hike in electric costs on our monthly bills. This is just a fact of life as nothing has as low a cost per MMbtu as coal.
Remember to send a Christmas card and a thank you to our boys and girls at the EPA and in Washington DC for that.

Coal plants are being shuttered because they are inefficient and much more expensive to replace than the modern combined cycle NG plants. With gas fired power plants the thermal energy gets recycled to boost efficiencies. Another big feature of the NG plants is they can ramp up almost instantly. So when extreme hot weather overloads the grid with AC loads, the NG plants are online right away, and ramp off quickly also. Some would suggest the extreme warm weather the nation is seeing is caused by the dirty coal plants worldwide, so maybe there are two wins in shuttering inefficient coal plants?

Electricity will be generated with the least expensive options first, hydro, nuke, coal, then NG. But with all the fracking and NG glut to the point where we are exporting it, NG could be the bridge energy until a better, cleaner, faster fuel comes online. It's not just the EPA, it's the arithmetic.

 

[wrightk20]

Sorry for interrupting this thread but reading this has made me wonder about a few things. I have a Royall outdoor boiler that is piped to my house and i have a grundfos 15-58 3 speed pump in my basement and this pumps all the time. Would it be beneficial for me to look into an ecm pump to maybe use less electricity? If what i'm thinking is correct if the pump varied the current and flow to get a certain delta T then when my furnace was not calling for heat it would back way off and run at the minimum until the furnace fan kicked on and then ramp up to maintain. Since my system has only one pump i would think it would be benificial to maintain some kind of flow at all times. Kevin

 

[Jeff S]

I have an update on my Taco 007, it has been connected to a kill a watt for 720 hours which is exactly 30 days and it has used 28.7 KW . In my area electricity is around 8 cents a kill o watt but when you add the taxes and other charges it comes out to 12 cents.

So here is the total for a months use 28.7 X .12 = $3.44

 

[kopeck]

$3.44 to stay warm, not to bad.

If you moved to an Alpha what's the realistic savings over the 007? I'm thinking it would take a bunch of years to make it back. If anything I would just run the 007 until it dies then think about upgrading.

K

 

[BoilerMan]

A plain old 007 is cheap-off-the-shelf and there are a bunch of places that stock them, even Lowes has them, so you can get one on a Sunday if needed. The Alpha or Stratos, do save electricity, and don't get me wrong I have LED lights in places in my house, but the cost of the unit vs electricity saved on a residential system may not be worth it. Now if you had a zone by circulator setup, just be going with ZV and a single circ would be the way to go (VS circ or not) Also, Taco makes more energy efficient ZVs electronic motorized ball valve, but again, if it were a new install, and not replacing something that is perfectly good........... If you were off-grid and wanted a boiler system, then it would be a whole different story.

TS

I hate to quote myself here, but this is what I was talking about. You are not going to get back the investment on a VS pump in a residential system. This is a general rule and is, of course, dependent system configuration and zone length etc etc....

The proof if here

I have an update on my Taco 007, it has been connected to a kill a watt for 720 hours which is exactly 30 days and it has used 28.7 KW . In my area electricity is around 8 cents a kill o watt but when you add the taxes and other charges it comes out to 12 cents.

So here is the total for a months use 28.7 X .12 = $3.44

Cost/Kwh is a driving factor, as well as ZV or circulator base system. Even if you halved that $3.44 with a VS pump you'd save $1.72 a month. Long time to recoup the extra $$ for the smart circulator. Plus if I may, a smart circulator could IMHO be less reliable in the long term due to more parts and circuitry. This does not by any means mean that I would not have one if it would save some real money, just pointing out a fact. If we are splitting hairs then I'd go with the KISS formula and a 007, if a real money saver (like gasser vs smoke dragon) then technology wins!

TS

 

[JP11]

Got simple OOR, 007, and 0011 pumps in my system.

Got a 00R and a 007 sitting on the shelf.. just in case. I've talked my wife thru a oil boiler nozzle change on the phone.. bet she could do a pump.

JP

 

[mikefrommaine]

I hate to quote myself here, but this is what I was talking about. You are not going to get back the investment on a VS pump in a residential system. This is a general rule and is, of course, dependent system configuration and zone length etc etc....

The proof if here


Cost/Kwh is a driving factor, as well as ZV or circulator base system. Even if you halved that $3.44 with a VS pump you'd save $1.72 a month. Long time to recoup the extra $$ for the smart circulator. Plus if I may, a smart circulator could IMHO be less reliable in the long term due to more parts and circuitry. This does not by any means mean that I would not have one if it would save some real money, just pointing out a fact. If we are splitting hairs then I'd go with the KISS formula and a 007, if a real money saver (like gasser vs smoke dragon) then technology wins!

TS

The other and I think bigger advantage to a VS pump is that it should reduce short cycling of the boiler. Which will help pay for the upgrade quicker when burning oil. But still helps a wood boiler burn more efficiently.

 

[SmokeEater]

I can't speak to the efficiency of the ECM motor over the traditional VS motors that Taco used in a couple of pumps that I have in my system. The boiler pump is a 007 delta T and is set with a delta T of 20* F. The boiler aquastat is set to 185*F and the 007 only pumps to a 100 gal buffer tank. The system pump is a 0012 delta T and pumps to the low temp radiant and the high temp baseboard and modine. Its sensors are measuring the delta T, again 20*F on the supply and return lines. It's my understanding that the pumps move more water as the temperature differences approach the set delta T. These 2 pumps are very quiet and seem to function just as I had planned.

 

[TheMightyMoe]

I can't speak to the efficiency of the ECM motor over the traditional VS motors that Taco used in a couple of pumps that I have in my system. The boiler pump is a 007 delta T and is set with a delta T of 20* F. The boiler aquastat is set to 185*F and the 007 only pumps to a 100 gal buffer tank. The system pump is a 0012 delta T and pumps to the low temp radiant and the high temp baseboard and modine. Its sensors are measuring the delta T, again 20*F on the supply and return lines. It's my understanding that the pumps move more water as the temperature differences approach the set delta T. These 2 pumps are very quiet and seem to function just as I had planned.

The other and I think bigger advantage to a VS pump is that it should reduce short cycling of the boiler. Which will help pay for the upgrade quicker when burning oil. But still helps a wood boiler burn more efficiently.

Makes sense to me, the savings come from burning efficiently, not electricity. Would take some work to figure out exact/semi savings.

 

[BoilerMan]

I guess I'm not making the connection of how burning efficiently is related to the flow through the boiler. I would think fire side settings would have to do with burning efficiently.

TS

 

[JP11]

I guess I'm not making the connection of how burning efficiently is related to the flow through the boiler. I would think fire side settings would have to do with burning efficiently.

TS

Exactly.. BTUs are BTUs.. how good you transfer the heat from firebox to water is a variable.. nothing to do with the pump.

The only REAL thing we are talking is.. are you better off spending more money on a pump, so you have a pump that will SLOW itself down so as to keep a more efficient delta T of 20.

Well.. with two more temp sensors to break, and more wire around the boiler that is vulnerable.. Probably not worth it.. FOR ME. To each his own.

 

[mikefrommaine]

I guess I'm not making the connection of how burning efficiently is related to the flow through the boiler. I would think fire side settings would have to do with burning efficiently.

TS

I agree there won't be much if any fuel savings for a indoor woodboiler with indoor storage. But a typical oil boiler will cycle less often with a delta t of 20. Which means there will be less standby losses up the flue. Taco claims an average consumer will save 50-60 dollars a year in fuel costs. And increase comfort presumably because there will be less variation in the house temps.
(broken link removed to http://www.sdsmarket.com/v/vspfiles/assets/images/spec_00-vdt_benefits.pdf)