In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.
The best Delta T for a mod-con?
My Alpine is installed and working, thanks to the great plumbers I ended up with who did a great job.
There is one thing that bothers me a bit. The pump that was included with my Alpine 210 boiler for use in primary loop is a Taco011. My installation is almost exactly as shown in the manual, with less than 10 feet of 1-1/4" copper pipe in the primary loop (plus 4 elbows, two T's, pump with integrated flow check plus ball valve flanges ) - in other words there is very little resistance to flow. When I figure the head loss for the primary loop and where that crosses the Taco011 pump curve, it indicates I should expect a 20 deg delta T. And indeed this is what my system is seeing - 20 degree delta T.
The boiler is specified in the manual to run from 20 to 35 degree delta T. So it is within spec and I'm not having any trouble. But wouldn't my system be running more efficiently if I put in a smaller primary pump so that I got an increased delta T? I can tell by using my hand that even when all zones are calling for heat that there is positive flow through the primary loop T's.
In general I guess I'm asking whether it wouldn't be better for a mod-con to operate at a higher delta T? Doesn't that increase the amount of time in condensing mode and improve efficiency?