Hi there..... times are hard as we all know..... and so a theoretical question if I may please. I have an oil fired combi boiler that is struggling to heat the whole of my house since it has been extended. I have aquired a second hand oil fired conventional boiler for free and wondered if it would be possible to plumb the conventional boiler in line with the combi ? (output of the combi into the return of the conventional..... etc) In theory the combined output of the 2 would more than satisfy the requirements ? Any issues anyone can see in principle ?