Solar hot water pump question- ECM circulator?

[Onokai]

I have have a 2 roof panel hot water assist system (older drain down type with a sunspool). I have had this system for over 30 years. The pump is a small taco bronze unit. I have replaced the guts 3 times over the years with this pump.
I'm thinking of replacing it with one of the new Grundfos ECM comfort pumps .they use less energy .I realize they cost about $160 upfront but since they use 5-8 watts they would over time save energy.. They do not get hot and I'm getting tired of replacing the taco pump guts.
Is this a good idea or is this pump the wrong unit for this application
One note is my system is 3/4 copper and this pump is 1/2 inch connections but as a simple recurculater I think this may be a non issue.
Any suggestions or ideas?
Mark

 

[Master Plumber Mark]

you have done well with that drain down system with the sun spool .....if it has lasted you 30 years...
I guess if you fool with it will you actually change the flow through the panels ??
if you can still get parts for the taco pump you might want to leave well enough alone....

 

[Sponsor]

 

[Onokai]

I have moved the panels twice on the roof-new addition and then a lifetime roof
replaced 80 gallon solar tank a few years ago due to it wearing out (Rheem)
Rebuilt the sunspool a few times (I have a spare rebuilt one now)
replaced the taco pump guts 3 times (last time in the fall-$77)
went thru a zillion flow swing check valves on the solar loop.
Silver soldered the panel a few times when both my freeze checks went bust.
still not bad considering I put this together when Jimmy Carter was President on a payback program from our utility
I was thinking the new pumps would save some electrical $ even though the old motor is 1/25th hp-its still old school motor
The Taco pump is the 006 bronze series-it does heat up at times from running.
I'll keep buying the guts for it.
It was a new idea as I was putting in the newer ECM Grundfos pump for hot water recurculator in the house.
Mark

 

[Master Plumber Mark]

that is really wild you still have it running.. I installed a bunch of drain down units with panels
back in 1981 in Denver colorado.... The water kind of panel is problematic for obvious reasons
and the constant waste of water was a problem in any desert situation......

I cant even remember what the controls looked like or the silinoid valve that pushed the water up
to the panels.... way too long ago...

 

[Onokai]

The valve is a sunspool and it been one of the best parts.
There's systems work best where winters are mild as it drains about 1 1/2 gallon a night when cold-in summer or hot climates it never drains down.
I love the system as it is all copper and there is no exchanger loss-as the water you use gets heated directly then stoted in the 80 gallon tank which feeds the gas water heater-a simple system
Where I live winters are mild (very little freezing)
I have a stockpile of spare parts -from panels to valves from all those older systems you put up along with everyone else.
The controller has run the whole time as its the original controller
really a great system-Just needs minor care and feeding. The swing checks these days I have found stop working in a year or two as they are not made like they used to make them. I only use USA ones but the one needs to stop back flow 100% when the system drains down.
Know of ny great 3/4 brass swing checks that do not reduce much flow and work at lower pressures?
The best ones I have found (our local plumb supply has cheap china stuff now which is not good) is from MacmasterCarr.
Mark