So, the pump's quite dead, and I've sourced a replacement. I had to track down a retailer by starting at the top - non-affiliated recommendations follow - Xylem Australia were very helpful* and put me in touch with Brown Brothers in Brisbane, who put me in contact with The Pump House in Beerwah. A new pump is on the way, and more about its future below.

*The sales manager for Xylem was keen to hear about the way the pump was being used, and was surprised that it didn't last longer, but conceded that running it for long periods quite close to its rated temperature probably contributed to its demise.

Now, onto the purpose of this post - how to make the new pump last longer?

Heat management is the issue - the pump needs to be able to run cooler - specifically, the pump motor where the electronics live. Quite difficult when there's hot water only 1 or 2 cm away, running through a highly-conductive bronze housing. There's a couple of ways to do this, and I'd like some opinions on my ideas.

1. The pump is located on the hot part of the loop - quite close to the output of the boiler. Would it be better to relocate the pump to the "cool" side of the loop, i.e. after the water has been through the towel rail and is considerably cooler than before?

2. Provide active cooling for the pump. I can put some cooling fins around the jacket, dab a little arctic silver to help, and wire a ducted computer fan in parallel with the thermostat circuit, i.e. the pump turns on, so does the fan. This is obvioulsy more complex than option 1, maybe I should do both?

2a. Drill holes either side of the motor housing (where all the electronics live), and duct some of the fan's air through the inside of the motor housing to carry heat away. Suitably grommeted and/or siliconed to keep moisture out. Also use netting or a filter on the fan's input side to keep dust and insects out.

Thoughts?