Why a series hook up?

[sparke]

Can anyone explain why some solid fuel boilers call for a parallel hook up with main boiler. While other manufacturers suggest a series hook up? Assuming nothing is different between the 2 systems other then the brand of wood boiler...

 

[wdc1160]

I have rarely seen manufacturers' recommend one way or another. Do you have a document from a manufacturer(s) that shows this recommendation?
Or a model??

 

[sparke]

Yes the documentation on my old Buderus says a parallel hook up is more efficient. But the documentation on the Greenfire calls for a series hook up....

 

[Nofossil]

The only advantage of series that I can see is that you only need one circulator and almost no control logic. The disadvantages seem to be far more significant. Certainly less efficient and greater chance that a problem in any component leaves you without heat.

 

[slowzuki]

Without knowing more about the details there are lots of reasons to do different setups. If you are not using your other boiler much, parallel is more efficient as it is another radiator in probably a poor location. On the other hand a series setup is simpler to hook into an existing system and keeps your other boiler warm and ready to fire without condensation problems in the heat exchanger.

If you have a condensing gas boiler, you should probably not use series and will probably need an HVAC designer to check over what you are doing. They are not really suitable for high temp demands like radiators but are perfect for in floor hydronics and can be sized for coils in air handlers etc.

 

[sparke]

I could have easily hooked Greenfire in series or parallel as it was already piped parallel. I did do what the manual said and hooked the Greenfire in series. I dont mind the radiator(oil boiler w/ hot water coil) because the oil unit helps heat a cold stairway/breezeway. I was just wondering why 2 different manufacturers suggest 2 different hook ups...

 

[Eric Johnson]

One potential problem with a series hookup is that now you've got two chimneys pulling your heat out into the great outdoors. I have a serial arrangement, but I shut down the gas burner completely and block the chimney. On newer boilers, you might have a damper that accomplishes the same thing.

 

[sparke]

One potential problem with a series hookup is that now you've got two chimneys pulling your heat out into the great outdoors. I have a serial arrangement, but I shut down the gas burner completely and block the chimney. On newer boilers, you might have a damper that accomplishes the same thing.

That is the exact reason I am trying to figure out why the manual suggests series hook up. Let me clarify to make sure I am saying what I mean.

The old boiler was piped what I call parallel. Here is a sketch.

Since I am having a bit of time expelling all the heat (smallest size I could get 90K BTU unit). I will leave it like this until I get water storage. Then the piping scheme will change again anyway...