# Question about Taco 007 IFC and water flow.



## Gasifier (Oct 30, 2011)

Does the integral flow check in a Taco 007 IFC stop all water from going by the pump?

If another pump is running in the system, will that create flow that will get by the 007 with IFC?


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## ewdudley (Oct 30, 2011)

Gasifier said:
			
		

> Does the integral flow check in a Taco 007 IFC stop all water from going by the pump?
> 
> If another pump is running in the system, will that create flow that will get by the 007 with IFC?



It depends.  The IFC gizmo adds about 2.5 feet H2O / 1 psi of head once flow is started, but it takes significantly more pressure to pop the disc open.

So if the other pump is pumping through a wide open circuit and there is a parallel path through the IFC, then as long as the head developed through the intended path never exceeds the pop-open pressure for the IFC then you're good to go. However I've never been able to find a spec on just what the pop-open pressure is.

But if it ever does pop open then it seems to me there will be some parallel flow through the IFC as long as there enough flow to keep the IFC valve open.


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## Gasifier (Oct 30, 2011)

ewdudley said:
			
		

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Here is what I am getting at. I have a Taco 007 IFC just above my boiler that moves the water from boiler to storage. Just before storage, about 4' of 1.5" pipe away, is a T. About a foot above that T is another Taco 007 IFC that pumps the water from boiler or storage, depending on if the first 007 is running, over to the distribution system in the other boiler room. So if the boiler aquastat is below it's set point, and the boiler or first 007 is off. Can the second 007 that should be pumping water from storage at that point be sucking water past the IFC of the first pump and taking water out of the boiler? Do you understand what I mean. You can see the two pumps, boiler and tank here. 

https://www.hearth.com/econtent/index.php/forums/viewthread/81767/ Thanks for your time EW.


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## ewdudley (Oct 30, 2011)

Gasifier said:
			
		

> Can the second 007 that should be pumping water from storage at that point be sucking water past the IFC of the first pump and taking water out of the boiler?



In general not a problem, which is good because so many are set up that way.  

If you look at the 'Simplest' it's an example of where there's a tee at the top and at the bottom of storage.  Load draws from one side and boiler fills from the other, nothing can go wrong because load will pull hot water from storage before it will pull any cold water up out of the boiler and through the resistance of all the extra pipe going over to the boiler.

Now move the connection point for the load side away from the top of storage, further and further towards the boiler.  If the piping over to the boiler is long and thin enough, at some point there will be some parallel flow through the boiler even though the water in storage is hotter and lighter.

Throw in the IFC and it would have to be a pretty unusual situation before you'd have to worry about it.

But with the return temperature protection mixing valve there can't be a problem in any event because as soon as it sees water less than its setpont on the 'C' port it will shut down any flow from the bottom of storage through the boiler.


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## Gasifier (Oct 30, 2011)

ewdudley said:
			
		

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Awesome. Thank you EW. You just put my mind at ease. When I asked my boiler guys this question when they were installing they said you shouldn't get any by the first IFC, and if you do it would be very minimal. So you have confirmed what they told me and I feel better about it now. 

How is your Attack boiler running?


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## ewdudley (Oct 30, 2011)

Gasifier said:
			
		

> How is your Attack boiler running?



Here's my 'review':

https://www.hearth.com/econtent/index.php/forums/viewthread/71715/

Now they have the DPX, which is a standard fire-tube downdraft.  I don't know if they've improved the insulation on the newer model.  And the Profi RK2001UA controller, even if were reliable, still doesn't address the end-of-burn-shutdown-logic for boilers with storage.


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## in hot water (Oct 30, 2011)

It is possible to get flow thru to return side if it is not checked, sometimes.  Anytime you have piping going straight up off a boiler or header you have the potential for "ghost" flow.  Hot water can travel up thru the core of a pipe, cooler water falling down the outside and cause a slow over-heating condition.  Are these 3 speed pumps running on the same speed?  Sometimes a larger output pump can back seat the smaller output pump's check.  It depends on what it is connected and the common piping.  See the drawing below from Caleffi idronics 5 "Zoning Hydronic Systems"

A circ with an internal check is a good idea and either a flow check or spring check on the return piping will assure no flow.  Unless of course you get a speck of dirt or debris in the check.

Also the common piping that both circs connect to has to be sized large enough to provide enough gpm for all the pumps, or zones connected to it. 

hr


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## Gasifier (Oct 31, 2011)

It is possible to get flow thru to return side if it is not checked, sometimes.  Anytime you have piping going straight up off a boiler or header you have the potential for â€œghostâ€ flow.  Hot water can travel up thru the core of a pipe, cooler water falling down the outside and cause a slow over-heating condition.  Are these 3 speed pumps running on the same speed?  Sometimes a larger output pump can back seat the smaller output pumpâ€™s check.  It depends on what it is connected and the common piping.  See the drawing below from Caleffi idronics 5 â€œZoning Hydronic Systemsâ€
A circ with an internal check is a good idea and either a flow check or spring check on the return piping will assure no flow.  Unless of course you get a speck of dirt or debris in the check.
Also the common piping that both circs connect to has to be sized large enough to provide enough gpm for all the pumps, or zones connected to it. 
hr 

Thanks for the response hot water. There are only two pumps of concern in this section of the entire system. They are both the Taco 007 IFC pumps. They are both the same size and all the piping is 1.5" copper. The only time there is a reduction in pipe in the whole system is when it goes to the manifold to feed the 3/4" lines to the zones. That is some distance away in the original boiler room with the oil fired boiler. The system is working great so far. I just started thinking about it and decided to find out for sure. When the boiler goes cold I wanted to be sure the second Taco pump would be taking the hot water out of the storage tank and not getting cooler water from the boiler past the first Taco. The storage tank gets me a few more hours of heating. That makes it nice when I work a ten hour day. The Wood Gun is going for 8 hours with no problems. When I come down in the morning the wood is all gone except for red coals. The tank is still up to temp though. That is with the fire box loaded half way with a mix of different size splits. A pretty good amount of wood. When it gets colder I will try some larger splits mixed in with some medium size ones. Have a good one.


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