is a taco vt2218 worth it at its current price?

ron

I bought a Taco VT2218 circulator back in 2015, was $200. The current price of it is $425. Why so much when a Grundfos Alpha is ~ @ 225 ?

• Why $425 for the vt2218 now, that seems high or is it me?
  
• What are comparable models of circulators to the VT2218 that are also delta-T or delta-P and self sensing and all that fancy stuff?
  
• I have a single zone one floor ranch using a 50 year old taco 007, I was thinking of replacing it with a VT2218 when I do some pipe work this summer. Should I? Is there a better choice of circulator keeping part cost in mind? I do not know if a 007 is the correct pump choice with regards to pump curve.
  
• There was mention within the last 1-2 years here about display issues with the vt2218. Any new info?
  

hot_rod

I think the higher cost is for the ∆T function. Do you need the delta T function?

For a single zone, just buy the basic ECM circ without all the options that you don't need.
I think all the pump brands now have a basic ECM offering.

dko

The Grundfos Alpha equivalent to Taco would be the VR1816, not the VT2218.

ron

academic'ish question: does not everything in hydronic heating (using copper fin baseboards) come down to a delta-T design? Boiler heats the water to 180°F , circulator pumps that through a zone of however long, the design is based on a delta-T of 20° so the water coming back into the boiler 20° cooler. So it's just a matter of the correct pump speed to achieve a correctdelta-T outcome, and if going with an infinitely variable speed pump aren't we beating around the same bush in the end to achieve some x° of delta-T?

so do i need the delta-t function... i think so doesn't everyone? Otherwise if using a variable circulator then to find out what s the proper speed (or pressure) to set it I need to get a supply and return temp probes on the pipes to monitor operating temps on some cold day and set the circulator accordingly? What happens if I do that on a 20°F day vs 40°F day? How does a "pro" install one of these? I thought I remember watching a taco univ. video where it was mentioned they install them and just set it on max and how that was not the solution.

I have not looked into all the types of circulators that are available today; I'm bummed the vt2218 is so much now. Is there any other "Delta-T" capable circulator besides the VT2218 for residential use? My fundamental question I guess is what's the best circulator to buy today to achieve optimumest operation, for a simple one zone setup with just circulator?

ethicalpaul

The water doesn't know it's 20F or 40F outside. It's generally room temperature minus 1 degree in the rooms, since the thermostat is calling for heat, so the delta will be about the same for the same rate on any given day, right?

It will vary some more with a setback but probably not very much. This opinion has no professional experience behind it, use at your own risk.

hot_rod

The delta T is an indication of the heat being transfered. It will change throughout the cycle, wide at the beginning, tighter near the end of the call. It doesn't need to or want to stay at one fixed value.

I'm of the opinion that the delta should not be held or constrained to one number, say 20 degrees.

It is much easier, accurate, to vary heat output by varying the SWT, as in outdoor reset controls, compared to varying output by flow changes. Temperature control is very is linear. Flow control not so much.

With one zone, chose the pump speed to give you the needed or desired flow, vary temperature to change output and keep the boiler efficiency high.

SteveSan

@ron There was mention within the last 1-2 years here about display issues with the vt2218. Any new info?

Here is what happened with the VT2218 circulator production.
There was a display issue, not a performance issue. There is a circuit board internally between the display and the controller of the circ, basically the controller for the display.

After some exhaustive digging around, some sleuthing, testing and more testing this is what we found.

This control board did not have its software correctly installed so therefore it will not tell you the current watt draw, nor will it tell you the GPM. The circ will read "07 WATTS 00 GPM" whether it is running in Delta T mode, fixed speed mode, any mode or setting you choose. However, it will still operate in whatever mode you have it programmed. The buttons still operate as intended.

So, what is affected out there? If you have a date code that shows between 0422 and 0423, the display may be compromised. The date code represents a month and year; we predate these circs by 4 months to allow for the circulators warranty based upon the time it take to leave Taco, go to our reps warehouse, get to the wholesaler and then to the jobsite. So that means that these circs were built between December 2021 and December 2022.

If your circulator falls within the date code above, is installed and the display is working properly, there is nothing you need to do. It will not fail later. This is a right out of the box situation

What do you do about it if you have one that has the incorrect display? Contact your wholesaler and your local Taco Rep. They will help you out. This is a high priority for us here at Taco so getting replacements back out is important. We are working with supply chain to get new circuit boards and chips (these things are in such high demand; every business sector has a rough time getting them). There is no in the field fix or programming that can be done. If you have one that has not been used or installed, still contact your distributor and local Taco rep.

If you have any questions, please give Taco Technical Services a call during normal business hours Mon-Fri 8am-5pm EST 401-942-8000

ron

ethicalpaul said:

The water doesn't know it's 20F or 40F outside. It's generally room temperature minus 1 degree in the rooms, since the thermostat is calling for heat, so the delta will be about the same for the same rate on any given day, right?

not sure if i understand your perspective on that statement/question.
The "delta", as in delta-T which refers to difference in Temperature between two things, constantly varies. The fundamental heat equation says greater heat transfer happens when there is greater delta-T. So for example if hot water baseboard heat is at 180°F it will transfer less heat per given amount of time to the colder room than if that water was 182°. Simple math there, is +2° realistically significant enough to factor in and worry about no. But what delta is then? Then, 40°F outside with 180° hot water baseboard (140° delta-T) versus 0°F outside with 160° hot water baseboard (160° delta-T) the latter will have faster heat transfer looked at it from that angle of numbers. But interior rooms are not at outside temperatures, they are vary from 60°-70° as they heat and cool, as the outside being colder is always pulling heat out of the house at some varying rate as the outside temp, wind, humidity, solar radiation vary.

so if there's a higher the delta-t of water in the boiler, that is the colder the return water the better the heat transfer will then be from the burning oil into that water via boiler heat exchanger? Thus less oil I should be using [theoretically] (which is the driving reason) ? So I want some minimum delta-T of return water vs supply water from the boiler but not too high a delta-T that causes condensation within an oil boiler correct? So should I shoot for a output water temp of 200°F and set the circ on a delta-T of 40° keeping return temp no less than 160° to prevent condensation within the oil boiler (because that's bad). I sort of agree, or can't find a reason to disagree, with delta-t should not be constrained to one number, i.e. 20° But having a delta-t circ that gives me the opportunity where I can push some buttons on it to set it, and with it's supply and return temp sensors showing me those numbers, seems like the way to go.

hot_rod

There are a number of different delta we talk about in heating lingo.
Indoor to outdoor, say you want 70° inside when it is 10° outside, so a 60°∆.
Not much you can do to control that outside temperature. That ∆ can change second by second.

There is a ∆ between the temperature at the heat emitter, lets use fin tube baseboard, and the room temperature. Assume the fin is 180° the air at the floor 68°. Supply is 180, return 160
500 X 5 gpm X (180- 160) = 50,000 btu/ hr. being delivered

The ∆ between the supply temperature to the fin tube and the return, this is what you want to lock in? That is what a fixed T circ will do.

Suppose the house is warm, stat satisfied. A cold winters day, you have a house full of guest arriving. As the door opens cold air replaces the warm air escaping, hot goes to cold.

Room temperature drops stat kicks on. Temperature at the floor drops to 60° the fin tube delta is now larger and as a result the changes 180 SWT vs 60° air temperature at the fin tube, output increases, ∆ at the boiler increases as the return from the fin tube decreases. The boiler is still supplying 180, but is getting cooler return, 150 perhaps due to the colder ambient at the floor, more temperature exchanged. 500 X 5 X (180- 150)= 75,000 btu/hr. is now being delivered to recover the cold space.

So without locking in a fixed ∆ on the pump, the fin tube output changes to meet the increased load. If you locked the circ at a 20∆ you have now constrained the system output to that one condition, the room recovery will be slower.

One concept of constrained T circ operation is that is lessens short cycling, on oversized boilers. Which it can by slowing the heat output. Is that a trade off you desire? There is absolutely no reason the system must always operate at the designed ∆.
The design ∆ is used to select pipe, pumps, heat emitters at that one specific condition, design condition. Problem is, the space is not always at design condition, and in fact in some winters may never even see design conditions.

See the example below for how often this location with a -5° design is actually at that condition based on 20 years of data

I prefer to let the delta of the S vs R move around as the load dictates, You can design around say a 20∆ but the system when cold may run 30 or more, closing down to 10, even 5∆ are the room temperature is satisfied. So the ∆ moves around a bit to best match the load at any given time.

Free Britney, free the T

ron

from a homeowner perspective all I care about is using the least amount of oil, because it cost money. So given that the house is already built (1987) and wgo-3 oil boiler is in place having 2 zones of heat, is there a way messing with circulator speed via delta-T methodology that will use the least amount of oil (to give highest efficiency of heat transfer from burned oil to heat in the house via finned baseboard) ? that's what I am trying to understand, so far you have not explicitly said yes but I'm not seeing an indication of no., take comfort and room temperature swings and anything else out of it just for argument's sake.

hot_rod

The temperature outside, the infiltration and the way you use the home, doors opening, etc dictates the heat load that the boiler (oil) needs to cover.
The best money you can spend to lessen oil use is to make sure the home is as well insulated and sealed as possible. A blower door test on a home of that vintage could show a lot of air leaks, which are usually the least amount of $$ to seal off.

Does the boiler match the heat load? Does it short cycle?, run for less than 10 minutes when it fires?

Does it have an outdoor reset control to vary the boiler operating temperature? The lower the boiler supply temperature the less oil you will burn. Matching the boiler SWT to the every changing load requirement is a good place to save fuel. Go to the tekmar site and read up on the concept of ODR. https://www.watts.com/our-story/brands/tekmar/references/how-outdoor-temperature-reset-controls-save-energy

See the attached slide.

Many agree comfort goes up when boilers run on outdoor reset control as you lessen the on off cycles. Yo can get close to constant circulation with a properly adjusted ODR in many cases. You save on cycle wear on electrical components also, gas valves, ignition, pump on/ off, etc.

These are the places I would look to reduce oil consumption. Forcing the circulator to run at some arbitrary ∆T may not provide the oil savings you are paying for?

An ECM delta P circ, with zone valves, would be my choice, spend the savings on any or all the above.

ethicalpaul

not sure if i understand your perspective on that statement/question.

...

Simple math there, is +2° realistically significant enough to factor in and worry about no. But what delta is then? Then, 40°F outside with 180° hot water baseboard (140° delta-T) versus 0°F outside with 160° hot water baseboard (160° delta-T) the latter will have faster heat transfer looked at it from that angle of numbers.

I was just saying that your baseboards are not outside, so the outside temp at any given time is mostly irrelevant to the delta T of your heating loops. I would say that bringing it into this discussion is confusing and distracting to what you're trying to figure out. (I don't use those words in a judgmental way).

But @hot_rod is making a lot of sense with his answers, listen to him and seal up your house to reduce your fuel usage.