are two boilers better than one

jonny88

im putting a new oil boiler into my house.i heard that two boilers are better than one as they can split the load.if this is the case how does the system work.what tells the secondary boiler to come on.i have seen the piping diagram where you have the primary and secondary loops which i understand.but is there controls that activate the secondary boiler,which will mean i am in the hands of the electrician.thanks for any input

Ironman

Depends...

Jonny,



It's gonna depend on the particulars of your job. We're gonna need more info: heat load, type of fuel, efficiency level, venting, etc.



Yes, there are controls that stage the boilers, in fact, a lot of mod/cons now have them built in.

Charlie from wmass

Tekmar and others

make controls that not only stage the boilers but rotate the fire order to even out run times on the boilers. In the dark ages I would simply pipe the boilers primary/ secondary and use aquastats to stage the fire. This meant one boiler would run more in the mild weather than the other. also with the boilers sizing I went for 2/3 load for each boiler so if one went down it would still keep the building from freezing even in the coldest weather. With Mod/cons and turn down rates it is still good for large structures as instead of the 5 to 1 turn down you can get a 7.5 to 1 if you divide the load as 2/3's 2/3s for each boiler. How big of a structure are you heating?