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 im unsure of is how to plumb that in, with a circulator on the return.

Any help here is really appreacted!













Thanks!

 

[Fitter30]

Boiler short cycles what controls the pumps ,what controls the boiler. What temp in and out do run the boiler and is there outdoor reset? Are there check valves on the two systems? What are t valves going to the baseboards?

 

[Sponsor]

 

[MassimoD]

Boiler short cycles what controls the pumps ,what controls the boiler. What temp in and out do run the boiler and is there outdoor reset? Are there check valves on the two systems? What are t valves going to the baseboards?

Hey Fitter.

The boiler is controlled by whatever factory set up is in there, the pumps are controlled by a taco pump controller. It has an adjustable aquastat. It is currently set at 150. There are check valves on the feed, one for each zone.

 

[Fitter30]

Boiler setpoint 150° guess the aqua stat is in the boiler? Which taco controller do u have sr 501? Room thermostats control pumps through the taco control? Using electronic thermostats? Mixing valve to lower temperature for radiate probably won't work with out expensive piping. Most floor radiate runs 80-95°
water. Cast boilers don't like return water under 135°. Injector pumping should work might have to add a tempering valve for the return water. I'm using electric Self limiting under ceramic tile, concrete on grade in a family room. Luv it.