Taco 007IFC and variable speed injection mixing

lekpeter

hi,
anyone see or had any problems with using Taco's 007IFC circulators on a variable speed injection radiant floor system.

thanks

lek

Kal Row

tekmar recomend - putting in a globe valve also...

to stopp down the flow so that pump is varied above 60% - it's hard to start at the low end - this goes for all pumps not just the taco

Weezbo

as the injection or system pump?

maybe reverse injection....

hydronicsmike

huh?

The Balancing Valve is there only to create head to make a pump give you the flow required at design condition when ramped up to 100%. No problem with running any Pump that tekmar recommends at low speed.

IE: If you only need 5GPM at design, a 007 can move as much as 18GPM at 3-4 ft of head. But if you create almost 10 ft of head with the Balancing Valve, the Pump only moves 5GPM when run at 100% and thats what we would need. It widens the Operating / Throtteling Range.

You from Reno, by chance?

Mike

hr

Early lessons

in VS pumping showed that the pumps need to start on the highest speed then ramp down. Mainly to get the checks to pop open, but also to assure the circ starts from a long off period with maximun torque. I think most all VS controls operate this way now.

Taco chose to install the check on the inlet side of the pump, not sure how, or if, that effects the low speed operation, or if their control starts on high ramp speed then tapers off.

Checks on the discharge side of a circ sees the pressure increase, that the circulator applies, when the pump fires up.

It's a balance act to build a check with low pop spring to stay open under low flow conditions, yet have enough fizz to stop flow when the pump is not running.

hot rod

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Weezbo

oops...

funny thing some how to gets mixed up in my vocabulary ...

Kal Row

nah - had gotten that from someone..

obviously didnt have the facts -
i was using a grundfos 3 speed and wanted to use the lowest speed for vari-injection and was told to use speed #2 or higher - is that true - and why?

hydronicsmike

no worries....

I have no idea why a Grundfos Pump would not work as a Variable Speed Injection Pump on Speed 1. I have been with tekmar for 5 years and this is the first I have heard of this. Maybe there was something before my time, but even the more 'Senior' guys (hope they dont read this post :-) ) here don't seem to know about this. So I don't know where this could have come from....

Regards,

Mike

Kal Row

could have come from your rep..cant remember anymore..

anyway i will try it on the lowest speed - and let ya know - i assume you guys do full-speed start and then ramp it down - it's a 15-58fc so the spring check has to be poped also, i see it running at 10% a lot (it's a 361) - the primary and secondary pipe is 1.25" as the gpm at design temp is 11.7gpm and the injection is 1" and pipes downward 18" from hot to cold

i has been working fine, even though i am using a ballvalve to create head in the injection loop - i just love to try things

Joe Mattiello

No Problem!!

The IFC version will give you enhanced performance because there will be no additional head because of an external check. Additionally, any one of the Taco, 00 series pumps can be used in a variable speed application, because of the wave chopping technique.

Taco, Inc.
Joe Mattiello
Technical Service Technician
joemat@taco-hvac.com
401-942-8000 X 484
www.taco-hvac.com

hydronicsmike

yes kal, please let me know about your findings. (NM)

Mike

Jeffrey Campbell

check valve

I was always told not to use a check valve in the injection loop. WIth the variable speed the pump could slow down so much that it may not be able to open the check valve. Does the IFC check valve have a design to alow flow at very low flow and head? Jeffrey Campbell

hydronicsmike

Our tests have indicated...

that those Check Valves that are built right into the Pumps are fairly easy to open and do not create the same ramping up or down of the Injection Pump as noticed with regular check valves. To my knowlege, those are also Plastic Check Valves that also do not create the chattering noise at low Injection Pump running speeds that we had received reports on with regular Swing Check Valves.

Standard Check Valves should not be used in Injection Loops. At least that is what is recommended.

Having been a (one of those bad) smokers for too many years now I can easily blow one of those built in Check Valves open, where others I have a hard time with. This tells me two things, for one, I can now see what the Pump is seeing when it operates at low speed and for two, that I should really quit smoking

Hope this helps. If you have further questions or concerns, please feel free to call me at any time at 250-545-7749, Ext. 214.

Regards,

Mike

Kal Row

works just fine on low speed....

and this night was 12f, and below my 15f outdoor design,
wasn't actually there to give you readings but the customer said that the heat was just fine - so the 361 must be kicking off the pump and then ramping to the injection speed

hydronicsmike

Perfect...

...Just what I thought.

It's nice when it works out like that

Mike