Taco vt2218 electronic issues

Franktg78

Ive recently purchased a new vt2218 from supplyhouse.com

Out of the box the electronics were faulty.  Set it for delta t supply initiall showed 97 supply 80 return delta set to 10 deg.   Display showed 07 watts and 00 gpm but it was running full speed.  Plugged it into a watt meter and sure enough watts were at 59.  Eventually supply and return temps came within 5 degrees of each other.  Supply was 98 return was 93.  Watts still showed 07 gpm 00 and plug in watt meter read 59 watts.  Called taco went through it with them they advised me to return it.  Called sh.com  went over it with them they issued me a return authorization.  Thinking this was a fluke i ordered another  vt2218 for another job.  My replacement and additional new pump arrive.  I swap out the bad one same issue with new one.  I swap out that one and same issue with third pump.  I now have three brand new vt2218 pumps all with faulty electronics from day one.   I called taco and got the feeling they know something is wrong.  Tech support told me ask the supplier for a pump out of a different lot.  I asked what he meant by that and he said just make sure you get the replacements from a different lot and you should be ok.

This doesnt help all my wasted travel time, on site time not to mention the issues still isnt resolved.  

Any one else running into this?

Thanks
Frankie
BTU Inc

hot_rod

Do you really need the delta T function? Get a 007e or other model that meets the load.

Franktg78

Put one in on one of my radiant manifols a couple years back as a test.  That particular manifold holds 10 deg delta t and room temp really nice even with 45 deg osa.   The Vt2218 seems to keep these spaces from hitting my tstat setpoint of 70 shutting the zone down.   I like the constant circulation and dont like the chill on the floor when it shuts off.  I have high output baseboars in all my 2nd floor spaces.  I did heat loss on them and nearly doubled the baseboard.  I need reset curve a bit higher for these spaces to stay at temp.  The out door reset curve with the delta t control keeps the radiant space aroud 69.  

Ive noticed with the regular 007 the delta t on anything but design gets verry narrow and my tstats satisfy and shut off the zone loops.  With the Vt2218 every loop on the manifold has a flow that varries to keep the 10 deg delta.

Currently my max loop temp is 110 deg at 0 deg osa

We just had 3 degree osa temps my loop temp was 105deg and all the rooms held 69 deg space temp.  

The vt2218 typically runs at low watts where the 007 is at 60 watts all day.

This is more of an experiment for me to watch and monitor performance.

Given the original ran 2 years on my home i put one in on a job and regret not keeping it simple.

eadam

I have recently had the same issue with the Taco 2218 pumps i had 7 in a row brand new out of box show only 7 watts and 0 gpms i called my distributor and Taco they definitely know they have an issue i was told it has to do with sensors on the pump. I have installed a many of these pumps and i never had an issue only recently is when i had any problems with the 2218. Taco is a good company hopefully they get it figured out soon here as im forced to look for another option due to the fact of the wasted time i had trouble shooting and return trips changing out pumps

hot_rod

The Vt2218 seems to keep these spaces from hitting my t stat setpoint of 70 shutting the zone down

So your room never gets to the setpoint you want? Or you purposely set the stat above the temperature you desire?
What happens as it warms up on the ODR, the room overshoots to 70?

It seems a properly dialed in ODR, properly sized electronic fixed speed circ would get the same result. Without the additional cost and tech of ∆T circulators.

Franktg78

My tstats are more like a high limit.  I have them set one or 2 degrees above my desired temp depending on the space.  I have fixed speed 007 pumps on other manifolds and each loop has a flow of .25gpm on average.  There are a couple loops taht are over my garage and those flows are .50 gpm.  

The manifild having the functional vt2218 does a nice job of keeping the 10 deg delta.  The functional pump is typically within a watt or two of a plug in watt meter i have to verrify consumption.

Reset curve is prety conservative
2 deg osa drop = 1 deg up on sys
Offset =  -15deg
Outdoor cut off 55 deg
Min water temp 70 deg
Max water temp 115 deg

Osa today 48 deg
System supply  set poin 86 deg

3200sq ft home
80,000 btu salveged navien ncb18e. I got from a site that threw it away.  When osa was 3 deg system temp was 105 all rooms were between 68-70 deg and the navien input was between 23% and 30% input

I get it way more complicated than needed.  But having this particular set up in my home is more of an experiment.  I dont have acces to design software or training to do paper calca so for me its trial and error.  I do commercial service in nyc not residential.  This particular project is more of a hobby for me to tinker with.

I never could grasp system performance benefits of  constant flow with varrying load.  The delta t pump concept just seemed to make sense.  When space load drops off dela t gets tighter with constant flow.  With a  delta t pump it tracks pretty consistent throught space load while also trimming watt usage.  Also seems to keep the space from hitting my tstat as high limits keeping floor temps consistently warm.  Im always open to new knowledge if my understand needs refinement.

Thanks
Frankie

Franktg78

Well 4th pump came in and same electronic issue.  Called taco again and got Tom in tech support.  They now have a known issue with the circuit board.  They now also have a range for the date codes.  The affected date code batches are 04/22 through 04/23.  Just a heads up to anyone considering these pumps do not take one with these date codes.  Good replacements are a ways out also.

Frankie

diftil

Just got a vt2218 installed yesterday, and it has exactly this issue (date code 2/23). Shows low watts and 0 GPM even when running at full speed, and it never adjusts speed. I've reached out to the Amazon 3rd party vendor that sold it to me, but has anyone heard from Taco about how this is to be resolved?

Seems like they ought to be having a recall and replacement from the manufacturer for these defective units, especially if there are so many of them that don't function at all.

EdTheHeaterMan

I believe they are working on it @diftil
https://forum.heatinghelp.com/discussion/191153/tacos-vt2218-delta-t-circulator

Franktg78

Thomas from tech support indicated they are aware of the issue.  Working replacements are a month or more out give or take.  I have to imaging there is alot of bad stock out there.  I imagine most people probably leave it running full speed just to get off the job.

When i called to return the bad ones i got from Supply house.com they confirmed they were aware of the issue and would send replacements.  They indicated the replacements would be out of the known bad date codes.  New ones arrived and both are 3/23 pumps within the range of defects.  Not even gona try them sending them back cant have any more time wasted than i already have.

jwilliamadams

Hi @Franktg78 . I just installed a second one because the first one was doing this same thing. So is the second. Just found this post when trying to search for any information. Glad I did, and glad Taco is aware of the issue. Thought I was losing my damn mind.

I'm replacing an older VT2218 (5-6 years) that burned out for some reason. The Delta-T is a great, energy saving feature.

hot_rod

jwilliamadams said:

Hi @Franktg78 . I just installed a second one because the first one was doing this same thing. So is the second. Just found this post when trying to search for any information. Glad I did, and glad Taco is aware of the issue. Thought I was losing my damn mind.

I'm replacing an older VT2218 (5-6 years) that burned out for some reason. The Delta-T is a great, energy saving feature.

Any idea on how much energy it saved you? Compared to what other circulator type?
Enough $$ to cover the cost of a new one?

Franktg78

Taco has gotten some good pumps in stock at the factory.  Tomas from tec support emailed me when then got them in.  Taco kindly set me the two pumps out directly at no chagre.  It helped to cover some of the lost time related to the failures.  Both new pumps worked and performed as expected.  Thanks Taco for helping out.

Hot rod in regards to electrical savings i need to try and find my notes from Last year.  I had a taco 007 and a vt2218 on similar load zones plugged into watt meters.  I had programmed my kwh cost including delivery charge into both watt meters.  I cant recall whar consumption difference was and dont want to guess.  Hopefully i can find it to post it.

Franktg78

Hot_rod

I lost my original notes and data log of run time and cost I did after installing the first vt2218.

I did plug in on of my 007 and the vt2218 into watt meters.  I entered my per kw cost of .25 this includes delivery charges.    Currently osa= 37, system temp 92 all rooms are 68-69 deg, flue 89 deg.

On a side note note if I run the ecm at constant speed with my flow .25gpm set via radiant manifolds the space reachs tstat sp of 71 and satisfies my tstat that is basically a high limit. When i switch back to delta t mode set at 10 deg the space stays 68-69 constantly in range of where i want it.  Untill solar gains kick in and bring temp up during the day.

Let me know long tem if these number justify the added cost.  I will leave the pumos and watt meters as is through the remainder of the winter.  Im curios where they end up myself.

Frankie

Franktg78

hot_rod

I just wonder the advantage to the delta T mode? It’s basically a Heat delivery limiting function, it constrains the system to a fixed output.
If your thermostat is set to 71 and the room only reached 68-69, seems it doesn’t cover the load.

Shouldn’t you be able to set the stat at 69 and it controls within a degree of that, depending on how your thermostat differential is set.

I would think a delta p ECM would have the same, maybe less power consumption. It only consumes what any open zones require, for flow and energy needed to obtain the proper gpm.

Some advantage to delta T if the boiler is oversized, as it limits flow rate. Are you running outdoor reset?

Franktg78

Hey hot rod

I am using reset
Reset curve is prety conservative
Outdoot cut off 55 deg

2 deg osa drop = 1 deg up on sys

Offset = -15deg

Outdoor cut off 55 deg

Min water temp 70 deg

Max water temp 115 deg

Boiler is an Navien ncb180 e i salvaged from the junk pile piped primary secondary

Boiler is 80,000 btu for heating ( i could probably do with a 60,000 btu unit or one with higher turndown.  

Home is 3,500 sq ft
2 story 
With basement

The first floor 80% extruded plate radiant in rooms where hardwood floor was left as is

20% rehau raupanel done in rooms i ripped up oak floring

My second floor is all high output rbi futera baseboard

When i installed this i did a heat loss calc.  Some rooms needed more than double existing standard baseboard to perform with low temp supply water.

The 2nd floor baseboard is what dictated my reset curve.  Its a bit more than what the radiant zones need temp wise.  I didnt want to add in a mixing valve and another reset controller so i tried the delta t pump. 

My morning coffe is still hotter then my heat supply on a single digit day.

In regards to not meeting tstat setpoint.  I want my spaces around 68-69.  I agree if my wife or kids decide to crank it up to 74 the space will most likely never get there without an outside influence like solar gain.   For me, my tstat is mearly a high limit.  Having the outdoor reset, outdoor cut off  and delta tp pump pretty much keep my pumps on constant and shut down only when and if the tstats satisfy.  I like the floor to always feel slightly warm and not cycle on and off.  Thats just me, most people would disagree.

I do chuckle anytime my kids try and jack up the tstas for more heat.  It always stays 68-69 its on cruise control.

Im gona do my best to keep the ecm and 007 pluged into the watt meters.  Curious to see electric cost difference between them. Ball parking 4-5 bucks a week on 007 i imagine the it will cost 100 bucks a season give or take.  Roi less than 3 years. 


Thanks agin for the discussion

Frankie

Mad Dog_2

Frankie...very cool 😎 experiment you are conducting in your home.  We think the same way.  I absolutely agree with you about the floors always idling at a minimum, warm. There's nothing worse than a cold 🥶 tile floor once you get used to radiant living.  Last year, my 3 zone radiant system in my Country Victorian Farmhouse had a few control and electric circuit  issues after almost 20 years of non stop service and the system was down for a month.  You know...the shoemakers kids....My kids were NOT happy 😕 with their now cold icy tile floors: "...hey Papa..when are you going to fix this?  If you don't have time, who can get the floor heat fixed????"   Shamed in to it again!  My lovely  mother Colleen (RIP) and my Long-suffering wife, Barbara knew how to FINALLY get me to fix the plumbing and heating in the house: "...ok...thats it...I'm calling so and so in to fix this !!!"
THAT!! Always worked and I put everything on hold until my own family's issue was fixed.    Where did you purchase those Watt Meters?   Great, productive discussion Hot 🔥 Rod and Frank!   Mad Dog 🐕 

Mad Dog_2

I've yet to see a company that doesn't have SOME issue from time to time.  Its all in how they handle it...just like us as installers.
Taco is a Helluva company and have always done an outstanding job of doing the right thing!  They truly care..It starts at the top.  Mad Dog

hot_rod

I never could grasp system performance benefits of  constant flow with varrying load.  The delta t pump concept just seemed to make sense.  When space load drops off dela t gets tighter with constant flow.  With a  delta t pump it tracks pretty consistent throught space load while also trimming watt usage.  Also seems to keep the space from hitting my tstat as high limits keeping floor temps consistently warm.  Im always open to new knowledge if my understand needs refinement.

With constant circulation, the circ runs at a fixed speed all heating season, my ECM runs around 20 W

Then you vary the SWT to match the load, I do this with my odr

Regulating heat output by temperature is very linear, about every degree relates to a degree, or whatever shift you chose

Varying heat output with flow is not nearly as linear

The constant circ is very common in Europe with panel rads and TRV or radiant

when Viessmann boilers first came to the US they didn’t have TT or any way to call them on

The German engineers couldn’t understand why you would want to turn you boiler on and off constantly?   Let it run, modulation output and temperature with modulation and ODR

daklein

I'm here at this thread because I just installed a new vt2218 with the similar / same issue.  I wish future me had given a heads up about this issue. I got it earlier this year,  advertised as open box good as new...  
Date code 12/22   22213
Regardless of what mode it's set to, it says 07 watts and 00 gpm.  It starts and runs for about 5 seconds then stops, and does that twice I think.  Temp sensors read appropriately, seem to work.  I want/need the deltaT mode for pumping through the water side of an air to water heat pump, in a hydronic system.  For now I stuck in a 07e spare that I had, but it can't set the flow via deltaT to match the heat pump capacity, and it's lower flow so the heat pump only runs at part load. 😕
I did leave an email to Taco support.

hot_rod

Are you sure delta T is the best control logic for the HP flow. Basically that control logic maintains a set delta, regardless of what the system needs or wants to give you the output you need. This is an example with fin tube, I believe the coil in the Hp would behave like this also. If you have the spec on the Hp, you could plot a similar graph and see how heat output behaves under constrained delta operation.

daklein

Thanks HotRod! No, I'm not sure, I may also try several fixed speeds along with deltaT. The goal being to operate the ASHP at a good overall COP and minimal cycling.
This is a homebrew ASHP system, evolving from a fin-tube gas boiler, eventually to radiant ASHP. Last winter put the buffer/storage tank with only a resistance element heat source, in place of the gas boiler. This year added a 3t ASHP to the airhandler for AC and air heating, with some refrigerant valving allowing to heat to the air coil or to a refrig-water coil (lower left in picture, which the 2218 pump would circulate). Next step is to replace some or all zones with radiant floor/wall loops, instead of fin tube, and let it put out more heat at lower supply temps. The main heat when we're home is a wood stove, and last December cold snap (SE Mich) while we were away kept house about 50dF with only the 3.8kw resistance source, ~1ton.
The ASHP is non-communicating, only the returning refrigerant state determines what load the outdoor unit runs to. The main system controller, HBX ECO-600 does outdoor reset for the main tank target temperature. I'd have to manually change how the HP circulator runs, maybe in milder weather a higher dT or lower circ pump speed, would run the HP at a medium load point, but in colder weather probably want lower dT or higher circ pump speed to run the HP at its full capacity?

SteveSan

@daklein I responded to your request. Please let me know if you need anything else.

hot_rod

Does  the heat pump compressor modulate or have  2 stage option? If not you need to meet the gpm requirement that the manufacturer requires
If you have  a modulating output heat pump, you may want the control on the heat pump to be able to modulate flow, with the compressor modulation so you always meet the minimum requirement.

With a buffer tank I would think a fixed output hp would want the flow requested by the manufacturer all the time. That’s why the 3 pipe buffer works well with heat pumps, return goes directly yo the HP without blending in the tank, providing the best m, most efficient operating condition

Here is the Spacepak spec

daklein

Wow, can't beat the excellent support from Taco, thanks @SteveSan.

HotRod, the ASHP outdoor is a GreeFlexx/MideaEvox/MrCoolUniversal (mine says MRC on it...). It has just compressor & reversing valve inputs so there's no specific stage input or communication with the indoor AH unit, but the variable speed compressor does run at different speeds, depending on what the returning refrigerant looks like. Running the AH blower at low or high speeds results in different operation of the outdoor unit. I'm assuming it changes the compressor speed, but it certainly changes electrical consumption of the outdoor unit. I have one thermostat in center of the house, controlling the heatpump for heating and cooling via the airhandler, and set that up for 2 stages heat & cool, which runs the blower at low or higher speeds, and I see the outdoor unit, at least the kw input changing appropriately. We used that for cooling over the summer, and heating initially this fall until now I got the water coil piped in. I'll attempt to measure COP at least qualitatively, with temp & flow across the water coil vs. electrical input, for different water coil LWT & flows.

It's sort of like a 3 pipe. The feed to the HP refrigerant:water coil is taken from after the old existing ZV return header, so it gets water returning from the zones. If the HP loop is a higher flow, it takes also from the bottom of the tank, or only from the tank if no zone is calling for heat, if I choose to run the HP solely on tank temp. I need to make a diagram of how its set up now. I'll add a second identical tank, and an indirect tank to preheat DHW, as well as make it so the HP loop can return directly to the load skipping the tank.

Your comments about deltaT for heating loops has me thinking: Maybe it could be worth having a variable speed pump for the main circulator. Lower flow, controlled to a certain dT, could result in actually lower return temps, and that could help the HP COP. Once some of the zones are converted to radiant and deliver heat at lower temps. But maybe that's just the same as adjusting the outdoor reset target temperature lower and run a higher loop flow.

cbrown

I can't find the date code on the circulator for warrantee replacement. I through the boxes out that may have the date codes on them. Wouldn't the date codes be on the units themselves?
CTB Consulting, Cortland Brown

hot_rod

daklein said:

Wow, can't beat the excellent support from Taco, thanks @SteveSan.

HotRod, the ASHP outdoor is a GreeFlexx/MideaEvox/MrCoolUniversal (mine says MRC on it...). It has just compressor & reversing valve inputs so there's no specific stage input or communication with the indoor AH unit, but the variable speed compressor does run at different speeds, depending on what the returning refrigerant looks like. Running the AH blower at low or high speeds results in different operation of the outdoor unit. I'm assuming it changes the compressor speed, but it certainly changes electrical consumption of the outdoor unit. I have one thermostat in center of the house, controlling the heatpump for heating and cooling via the airhandler, and set that up for 2 stages heat & cool, which runs the blower at low or higher speeds, and I see the outdoor unit, at least the kw input changing appropriately. We used that for cooling over the summer, and heating initially this fall until now I got the water coil piped in. I'll attempt to measure COP at least qualitatively, with temp & flow across the water coil vs. electrical input, for different water coil LWT & flows.

It's sort of like a 3 pipe. The feed to the HP refrigerant:water coil is taken from after the old existing ZV return header, so it gets water returning from the zones. If the HP loop is a higher flow, it takes also from the bottom of the tank, or only from the tank if no zone is calling for heat, if I choose to run the HP solely on tank temp. I need to make a diagram of how its set up now. I'll add a second identical tank, and an indirect tank to preheat DHW, as well as make it so the HP loop can return directly to the load skipping the tank.

Your comments about deltaT for heating loops has me thinking: Maybe it could be worth having a variable speed pump for the main circulator. Lower flow, controlled to a certain dT, could result in actually lower return temps, and that could help the HP COP. Once some of the zones are converted to radiant and deliver heat at lower temps. But maybe that's just the same as adjusting the outdoor reset target temperature lower and run a higher loop flow.

There are some pros and cons to limiting or constraining the operating ∆T of the distribution. We talked about it in a few Idronics, Here are some of the considerations. ODR can get them balled up, there have been a few posts, over the years, from the field about that challenge, here at HH.

SteveSan

@cbrown The manufacturer's date code is listed on the motor data tag under the part number ( VT2218 ) and you have 3 years from that date code through place of purchase for any warranty. Please call Taco Technical Service 401-942-8000 during normal business hours 8am-5pm EST Mon-Fri with any questions.