Greenwood/ Seton plumbing help

[Mule3010]

Merry Christmas All!
Can anyone help me with pump location on Greenwood. Should it be on the supply or return with closed system, no plate exchanger. And are you running balancing valve and mixing valve. Thanks in advance.

Hey Matt in NH if you see this please call Ben in Oh. 419)305-1764

 

[Hunderliggur]

Return side gives you lower operating temperature and lowers possbility of cavitation - in general. Not familiar with the Greenwood in particular.

 

[Jesse-M]

Merry Christmas All!
Can anyone help me with pump location on Greenwood. Should it be on the supply or return with closed system, no plate exchanger. And are you running balancing valve and mixing valve. Thanks in advance.

Hey Matt in NH if you see this please call Ben in Oh. 419)305-1764

I ran mine on the return, ( where the pressure vessel enters the boiler ) and do not have any sort of valve.

( Homemade Seton )

 

[91220da]

My pump is on the return with a Danforth mixing valve on the supply line that sends water above 140 to the return which enters just before the pump. Jesse that is an awesome draft inducer set up you built. How does it perform?

 

[Mule3010]

I have the pump on the return (Taco 0013), but the
installation book shows it on the supply and also a mixing valve and balancing valve. I am planning a Tekmar 3way manual mixing valve? But what is the purpose of the balancing valve?
I am open to all ideas and or suggestions. Thank You!

 

[Jesse-M]

My pump is on the return with a Danforth mixing valve on the supply line that sends water above 140 to the return which enters just before the pump. Jesse that is an awesome draft inducer set up you built. How does it perform?

Works well for me, here is the thread I started for it.........click here for fan thread

 

[Gooserider]

Return side gives you lower operating temperature and lowers possbility of cavitation - in general. Not familiar with the Greenwood in particular.

Correct as far as it goes, as cooler water has a greater tolerance for a pressure drop w/o cavitating, but the other big item is that you want to look at where your "Point of No Pressure Change" is - which is the point where your expansion tank ties into the system... The theory says that in a closed system, the dynamic pressure at that point can NOT be changed (the static pressure in the entire system can be) so you should always try to pump AWAY from that point.

Doing so will add the pump head pressure to the system pressure on the output side, while the PoNPC will keep the pressure on the inlet side constant, which reduces the chances for cavitation. Since the expansion tank usually ties into the boiler output side, it is best to put the pump on the boiler output side, downstream of the expansion tank.

Older systems used to put the pump on the return line in order to get lower temps, as the pump technology of the time didn't like high operating temperatures. Modern pumps have improved their ability to take the heat, so pumping away is now preferable - at least according to the experts...

This isn't Greenwood specific, but is a general rule for any system...

Gooserider

 

[Hunderliggur]

As they say, you performance will vary. There are some many configurations and specific applications that it is not always possible to meet everyone's expectations.

As far as I understand it, if you are using something like a Danfoss valve (constant temperature) to keep the boiler temps at 140 or higher, the circulator would have to be on the return side between the Danfoss and the boiler. If the circulator was downstream of the expansion tank (in my case and many others), there would be no circulation in the tight Danfoss loop at the boiler. You may be able to put the circulator on the supply side in a no storage system in a "boiler supply - Press/Temp relief - air purge/expansion - circulator - Tee - Danfoss - boiler return - boiler". My boiler is in an outbuilding and my 1000 gal storage and 86 gal expansion are in the basement of the house so I have a "boiler supply - Press/Temp relief - air purge - Tee - Danfoss - circulator - boiler return - boiler" in the outbuilding.

Even though the pumps are rated for higher temperaturs, I find running below the limits always helps with longevity.

Just my 2 cents worth.