Tigerloop to save wear and tear on pump?

How old is the boiler? How often has the pump been replaced? What is the pump spec in regards oil lift? How long and how big is the feed line? Many elbows etc.

I think the old adage "if it ain't broke don't fix it" applies, depending a on the answers to the above questions.

Can't see how it's going to do either of those. Fuel consumption is basically down to jet size and oil pressure. Emissions down to quality of oil and how much air is let in. Pressure and air should be both adjusted to produce the best burn, I fail to see how inlet pressure can affect those settings. The pump, in single pipe mode, will be circulating the oil within itself via the bypass.

This seems a reasonable and clear explantion of why tiger loops might be required (once you get past the first couple of paras):

Certainly when we get a delivery of oil the level in the sight tube drops by about a cm in the 24 hours afterwards then remains stable. I put this down to air in the fuel that settles out.

The 4' lift you have with an empty tank is about 0.13 bar of pressure reduction. That's tiny I doubt that little pressure reduction will release much dissovled air. Note the empty tank, with it full you may have positive pressure at the pump or be very close.

Waste of money.

Your suppliers presumably sell you oil by volume. Is it in their interests to include some air in the oil deliberately?

stable. I

I suspect that the pump wear will relate to the number of revolutions which will be the same.

If there is large lift and/or a long bendy/constricted pipe run there is some risk of cavitation in the pump. You don't want that as it will damage the pump.

I'm struggling to work out how a tigerloop would stop cavitation, the only thing lifting/pulling the oil is the pump. AIUI a tigerloop removes actual bubbles but cavitation is caused by the low pressure on the pump parts releasing dissolved gases, when the pressure goes back up the gas redissolves...