Anyone ever install a outdoor reset control on a boiler. I found one made by taco, but wasn't sure if they were hard ti install. I know the sensor has to be on the North side of the house. Not sure if you need a argo control unit for the wiring?

You will need to follow the directions exactly that come with the unit you decide to buy or use. I have installed many of those style controls but there are many different types of boiler setups so that is why I recommend following the instructions.

I decided to install indirect water heater. Homeowner has oil fired,slantfin,tankless boiler. The boiler doesn't drop below 160 degrees with out firing back up. This should help a little.

Just make sure the oil fired boilers temp does not get to low. Most if not all outdoor resets are completely adjustable to compensate for to cold of a return water temp.

With an indirect water heater on a boiler that is not a really large old boiler you should not be maintaining any water temperature. It would not make sense to spend the money on an indirect and still maintain temperature in the boiler.
All the boilers made today want cold start even with indirects.

The wiring of the PC700 outdoor reset if fairly simply compared to some of the others.

We didn't do the out door reset. Maybe next time I'll get to try it out. For now they'll save some money with the 40 gallon crown super store. You'r right about the temperature to cold and you start having problems with the cast iron. I'll start looking for high eff oil fired boiler.