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[caper]

should I make this change as well in the spring, system has the zone valves and circ pump pulling the water instead of pushing the water when heat is called for ,is there any difference, its been like this for three yrs now,

[LittleJohn]

What do you mean PULLING vs PUSHING???

Typically you want to "pump away" from boiler or heat source; an entire book was written on the subject by the way. 

[Sluggo]

I have one pump doing the same thing.  It makes difference!

[caper]

Maybe I explained this wrong, when the zone calls for heat the hot water (supply) goes thru the rads or in floor right away, then it goes thru the zone valve and pump on the way back to the return to the heat exchanger, im pretty sure this is how it works,seems to work fine,however should I change it in the spring,learning a lot from all of you on this site.....it appears I have a few things that need changing.

[RSI]

If it is a pressurized system it is fine. If it is an open system it should be before.

[caper]

thanks RSI, and yes its pressurized, one more thing I don't gotta change,thats good

[LittleJohn]

IF IT AINT BROKE, DON'T TRY AND FIX IT

If I were to start over from scratch I would say move the pump to the outlet of the heat exchanger, but if you and more importantly the WIFEY are happy with how it works; I would leave well enough alone

[Sprinter]

Boiler pumps do not push or pull, that's why they are called circulators.  They move water by creating a pressure differential on either side of the circulator. High on the outlet side and low on the inlet. Physics tells us water always wants to equalize, as exactly why the water from the low side moves to the high side. These don't work like a lift pump.

There are videos here explaining this in very simple detail, or just visit Taco site. "Pumping away" describes the effects and reasons why circ placement can be bad in some locations. It can cause leaks, pressure problems, air into the system, either right away or down the road.

Good luck

[aries9245]

I agree pumping away book is a must have if your at all confused it helped me re design my system to a primary and secondary system after having lots of issues pressure and air in system do yourself a favor and pick it up.. I found it on amazon

[slimjim]

Let's see if I can explain why I like to pump away (circ on supply ) as opposed to  circ on return.  Air elimination is key to either but lets think about it, very few application ever get 100% of the air out of a system on initial start up, air likes to move upwards in water, lets say a glug of air is left in a loop and it eventually gets worked back to the return header, when it reaches the circ on the return side it will stop the flow as a circ will not push or pull air down, installed vertically on the supply side of a loop, the air will naturally move upward through the circ, out through the loop and eventually work it's way through the system back to the air separator or bottle vent and vented out of the system, with isolation flanges on the circ, the little bit of air introduced to the system when changing out a circ will typically work it's way through the system without the PITA of purging that loop. Think your systems out, bottle vents placed up high on a closed loop are your friend!

[atvalaska]

boiler guy I know sayz its like this...pump away ..the slowest the water will be....... will be before the pump and all the mico bubbles and such will have "drifted"  to the top of the line =easy air removal...

[RSI]

Let's see if I can explain why I like to pump away (circ on supply ) as opposed to  circ on return.  Air elimination is key to either but lets think about it, very few application ever get 100% of the air out of a system on initial start up, air likes to move upwards in water, lets say a glug of air is left in a loop and it eventually gets worked back to the return header, when it reaches the circ on the return side it will stop the flow as a circ will not push or pull air down, installed vertically on the supply side of a loop, the air will naturally move upward through the circ, out through the loop and eventually work it's way through the system back to the air separator or bottle vent and vented out of the system, with isolation flanges on the circ, the little bit of air introduced to the system when changing out a circ will typically work it's way through the system without the PITA of purging that loop. Think your systems out, bottle vents placed up high on a closed loop are your friend!

I agree but if the pump is on the return and the whole system was installed by an HVAC company, leave it alone unless there is a problem with it.

[slimjim]

Agreed, no sense fixing what ain't broke but if starting from scratch then pumping away is a better choice.

[aries9245]

As the book said the reason the pump was installed on the return side to make it easier for shipping and instead of changing it back to what's the right way installers just got lazy..