Primary Secondary Question

Mark Mathys

I am going to add a second boiler to my hot-water system and would like to use primary secondary piping so I can run both boilers if necessary. My question is can I tee into a vertical pipe? The pump is on the cold side of the boiler and the flow in this line is downward. I was thinking of taping in here, right before the pump, maybe there is a better place?

Thanks

Dan_12

Could you post a picture or drawing of the existing and the proposed. thanks dan

Mark Mathys

Primary Secondary Question

Hi Dan

I have attached a drawing showing what I would like to do. Also a poor picture of the current boiler. I am attaching a wood-fired boiler that will be in the garage, the water lines will be in an insulated box underground but I will not be using glycol in the system therefore I will need to keep the water circulating in the system to prevent freezing (I live in ND).

My plan is to control pump #3 with a thermostat and then add a second thermostat to control the original gas boiler if the wood boiler can't keep up with the demand. That is why I want to run both boilers at the same time.

Thanks in advance for any advice you might be able to offer.

Mark Mathys

I decided maybe I should move everything to the hot side of the exisitng boiler and relocate the current circulator to the other side. I can tap in between the boiler and the pump and hookup the old expansion tanke so I am "pumping away". With my previous drawing I was concerned about cracking the boiler with the hot water that is circulationg in the wood boiler circuit. With this revision at least the hot water would travel through the whole system before returning to the existing gas boiler.

I hope someone can help me with this as it is starting to get cold.

Mark

Weezbo

Pumping Away.....

You indeed will be pumping away...how ever the number of pumps isnt what defines "Pumping Away".........the wood boiler is something that ,i think,likes a buffer tank...there is a guy here who likes his wood boiler he is good at it ...maybe he will drop in and see your post.

Einsiedler_2

how bout this way

you may find this approach a lil more effective.

regards,
EIN

hr

Go with EIN,s approch

In your drawing you will need to run both pumps, which put them in series for one thing, circulates hot water through the unfired boiler, and doesn't have a true hydraulic uncoupling.

With the PS you get all the good features and can fire one or both boilers with out bothering the other. Cost you another pump, but well worth the effort.

Like to see you use check pumps, on the boilers, for added protection against ghost flows.

hot rod

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Kal Row

go to tekmar and read

http://www.tekmarcontrols.com/acrobat/a261.pdf

http://www.tekmarcontrols.com/acrobat/a361.pdf

lots of good info on that site
i would use pumps with internal spring checks only
slaves you lots of trouble

Mark Mathys

Thanks for the ideas.

Ein I would like to use the method in your drawing. If you look at my diagram you can see that the house is split into 2 circuits, fed in the middle. Is this is problem? or can I just hook the feed and return together with a pump and then tee in both boilers before the pump. Could you draw me another picture?

The 2 circuit split has me a little confused.

Mark