by australsolarier » Tue Aug 02, 2016 3:47 pm
well, if you buy a cheap chinese made circulation pump the failure rate will be way higher than if you invest in a grundfos or other quality made pump. the price will be 3 times higher, or more, so will be the reliability and your ease of mind.
i have 3 grundfos pumps, no problem, two of the chinese pumps failed shortly after installation. i could tap them with the screw driver and they would stall and after more taping unstall again. i suppose that is alright if you sit next to the pump 24h/day and can tap them back to live when they stall. so i bought the grundfos pumps and haven't look back since. they also use less electricity and circulate to a higher distance vertically at start up. plus they can be pmw controlled, whilst my chinese pumps sounded like a small jackhammer when in low speed.
i would certainly expect the quality pump to last 10 years in daily usage.