New York Tranquility 27 fine tuning

Can anybody explain this. Why his pressure drop did not change if hi lowered the flow speed? I didn't get that. My system is opposite I have 7psi pressure drop , it's too high. Same equipment just (5ton). I'm trying to lower it.

 

I agree with Chris on this one. It is just how it works. One takes GPM and head loss and plots it on the pump curves from the manufacturer. One then takes the pump size that just covers the real time point on the graph.

One of the reasons I down play push/pull flow centers.

A Wilo factory guy told me all pumps are over sized. He did sell me on ECM drive pumps, and bought diner.

I did get to play with the new CM stuff Friday. I am re-thinking my opinion of their concepts. ECM pump, new cmx2 board, with a communicating thermostat and an ECM blower drive. We added a buffering tank for DHW, so I got to use all five senses to monitor real life VS t-stat tales.

The call was two fold add the tank tune the system.

I did not get the time I wanted to spend reading the I/O manuals so I took real time measuring points to compare to the on board sensors to the stat. I can now tune this system by email. I do not have enough info to say whether I like them picking a pump for my design yet.

Mark

 

Another winter, another quest for expanding my understanding...

I put together a flow meter just like the one suggested earlier in this thread, minus the pressure gauge (see attachment; thank you Rgausman). With my 3-speed 26-99 pump on high/medium/low, I'm measuring 7/6/5 gpm. Focusing on just the high speed for now, I'm thinking that 7 gpm is a little low based on the 3 gpm per ton rule of thumb. ClimateMaster's IOM for my unit says 2.25 gpm per ton is ok too. I took pressure readings at the P/T ports and the pressure drop table suggests maybe 8 gpm for what I measure (close enough?).

Questions:

1. Could the flow meter be a little restrictive, lowering the flow?
2. My delta T at the coax is in the 8F area, which is within range of the performance data, with sub-optimal flow. Why?
3. It was suggested that I may need a bigger or second pump. Is this still recommended?

 

1) Yes, your flow got worse with the meter
2) 8F is on the high side, but at 45F EWT the HP can extract more heat out of the water, thus it is within the performance range.
3) Your EWT is around 45F right now, correct? Your performance seems fine. Keep the pump, don't waste more pumping power.

 

Get some knowledge.

www.grundfos.us/handbook

Promo code 101

If that does not work I will send you my extra copy.

Good luck,

Mark

 

Thanks Doc and Mark. Yes, my EWT is hovering around 45F. Thankfully it didn't get much lower than that since I started monitoring a year ago.

Mark - the link you gave took me to just the Grundfos landing page. I searched and found the "Grundfos HVAC handbook". Is that the document you recommend looking at?

 

Yes. Lots of stuff to learn there.