Hydronic pumps, PSC vs ECM motors

Daox · 10-18-12, 10:23 AM

I posted this in my solar pump selection thread, but also wanted to make its own thread since it extends beyond solar pumps and into hydronics heating in general as well as heat pump setups.

I've been brushing up on my hydronics lately because of the solar project and also installing hydronic floor heating in my office. I was reading John Siegenthaller's 'Modern Hydroinc Heating' and happened to be reading the chapter on pump selection. He mentioned that it is quite common to find that, going from a PSC (permanent split capacitor) motored pump to a ECM (electronically commutated motor) pump will double your efficiency! This isn't even taking into account the benefit of the variable speed advantage that the ECM motors provide.

My Grundfos UP15-100f uses a PSC type motor. With a current draw of 135W, I'd be very happy to see something in the 65-70W draw as a replacement. So, I shall be looking into what options are out there for ECM motor pumps, not only for the solar setup, but also my hydronic floor heating setup.

In the book, he continues on to show that a 85W pump operated for 3500 hours per year with an electricity cost of $.14 per kWh (a bit high) will uses almost $1400 in electricity over a 20 year life. So, reducing that number in half gives quite a bit of room for cost savings in a pump even if the new pump costs substancially more.

Does anyone know what is available for ECM pumps?

10-18-12, 10:23 AM	#1
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Hydronic pumps, PSC vs ECM motors I posted this in my solar pump selection thread, but also wanted to make its own thread since it extends beyond solar pumps and into hydronics heating in general as well as heat pump setups. I've been brushing up on my hydronics lately because of the solar project and also installing hydronic floor heating in my office. I was reading John Siegenthaller's 'Modern Hydroinc Heating' and happened to be reading the chapter on pump selection. He mentioned that it is quite common to find that, going from a PSC (permanent split capacitor) motored pump to a ECM (electronically commutated motor) pump will double your efficiency! This isn't even taking into account the benefit of the variable speed advantage that the ECM motors provide. My Grundfos UP15-100f uses a PSC type motor. With a current draw of 135W, I'd be very happy to see something in the 65-70W draw as a replacement. So, I shall be looking into what options are out there for ECM motor pumps, not only for the solar setup, but also my hydronic floor heating setup. In the book, he continues on to show that a 85W pump operated for 3500 hours per year with an electricity cost of $.14 per kWh (a bit high) will uses almost $1400 in electricity over a 20 year life. So, reducing that number in half gives quite a bit of room for cost savings in a pump even if the new pump costs substancially more. Does anyone know what is available for ECM pumps? __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. Last edited by Daox; 10-18-12 at 10:56 AM..