Help Adding a Radiant Zone and Replumbing Boiler return

MassimoD

Hey Everyone!



Firstly Thanks for all the help here. I recently bought a house that has an older Weil McClain Boiler, pics are below.



I recently renovated my main floor and added some radiant tubing in my kitchen. I want to add a separate zone, and also add zone control valves so I can better control my heat! I could use some advice on how to plumb things. I am an engineer, I can solder pipe and also have pex tools.



Here is my initial plan, I want to repipe the return, making sure everything is the same size. Currently it is not. I want to add Two zones, one for the radiant heat and one for future plans when we renovate our basement, currently has no heat.



Currently the first floor is one a zone with a taco circulator, that has the larger 1 inch pipe and hydronic loop with t valves going up to the baseboard. I plan to leave that alone. The second floor (apartment) is on the 1/2 inch line and its own circulator. They each have there own flow control diverters on the feed and the circulators are on the return. I believe the zone valves will help me get things running more efficiently as it seems the boiler cycles quite a bit.



As for the radiant heat, I understand I need to plumb in a mixing valve. That makes sense, but I have also read that flow diverters work better as they allow pressure to be maintained in the loop. What I'm unsure of is how to plumb that in, with a circulator on the return.













Any help here is really appreciated!

Thanks!

MikeL_2

  Yes, a re-pipe is a good idea. At the minimum, change the circulator piping so they aren't fighting each other trying to get water into the boiler. Ideally, move the circulators to the supply piping pumping away from the expansion tank.
   I'm a firm believer in constant circulation for radiant systems. Viega makes a hydronic mixing block that is easy to install and includes an on board circulator,  programable / adjustable outdoor reset, and warm weather shutdown.
  Primary / secondary piping or a buffer tank would help you, too - that's a lot of boiler for periods of small demand.
  Others that contribute here may chime in with suggestions, and Heating Help offers excellent books to guide you through upgrades.

hot_rod

Search this  article for some piping options
A 3 way thermostatic valve us the best option

MassimoD

MikeL_2 said:

  Yes, a re-pipe is a good idea. At the minimum, change the circulator piping so they aren't fighting each other trying to get water into the boiler. Ideally, move the circulators to the supply piping pumping away from the expansion tank.
   I'm a firm believer in constant circulation for radiant systems. Viega makes a hydronic mixing block that is easy to install and includes an on board circulator,  programable / adjustable outdoor reset, and warm weather shutdown.
  Primary / secondary piping or a buffer tank would help you, too - that's a lot of boiler for periods of small demand.
  Others that contribute here may chime in with suggestions, and Heating Help offers excellent books to guide you through upgrades.

Thanks Mike! I always remember reading that the return side extends life due to the lower temps?

Just to be clear here, I am keeping 2 zones with baseboard heat, and adding 2 zones. 1 zone for baseboard heat in the basement and 1 for in floor radiant heat, roughly a 200' loop buried in a concrete mud job.

I appreciate your input, the boiler cycles constantly even if the heat isnt being demanded.