Seeking radiant floor heating system design feedback

theoj

Hi,
I am looking for a validation for the radiant floor heading design I am about to implement. The Warmboard panels and I am installing right now. I used the "Hydronic Design Studio Pro V2 for calculating the system and did the resulting design myself.

The property is located in the Santa Cruz, CA area and has coastal climate. The house itself is narrow, about 15 feet wide and build at a hill side. From the boiler location to the top most manifold it is about 20 to 24 feet in hight difference. The supply pipe lengths between are actually shorter as described, the long one is probably more 60-80 feet.

The planned components are identified in the diagram below.



The plan above is created based on the tool input, the Hydronic Heating book and and manual for the Bosch heater.

Open Questions

1. Are there any design flaws, which need correction?
   
2. Is the one pump enough for the needed circulation?
   
3. Is 1" common copper big enough for the heater side piping or does it need to be 1 1/4"?
   
4. Is 3/4" PEX-AL-PEX big enough for the needed flow?
   
5. Does the mixing valve still makes sense to ensure the needed system temperature or would it be better to just rely on the mod gas boiler?
   
6. Does the Manifold calculation make sense or what corrections are needed?
   
7. Is Bosch a good boiler for the setup or is a different boiler/sizing preferable?
   

Credit: I am not a heating professional and used images from the Modern Hydroponics Heating book by John Siegenthaler for the visualization combined with the screen output from the Hydronic Design Studio Pro V2 tool.

STEVEusaPA

Seems like you have odd choices for your manifolds related to rooms & btu loads. For example you have the same manifold doing the living room as the 2 of the bedrooms.
Where is the thermostat? Or do you intend to use constant circulation, actuator heads on each loop, etc.
Where's the circulator on the boiler loop or is it internal?
As much as I like Webstone, I wouldn't use their closely spaced tee set up.
Why 2 different design temperatures?

Ironman

You don't need the mixing valve, the boiler's ODR control can take care of SWT.

theoj

Hi @STEVEusaPA , Hi @Ironman,
Thanks for the quick responses and feedback!

House layout and resulting design limitations

Steve, you are right the manifold locations are dictated by the house design, which is narrow and staggered. Effectively (with the exception of master bathroom and bedroom every room is on a different level. The setup is as following.

The rooms have their on actuator(s) and thermostats as following:

1. Thermostat 1 [Loop 1]
   Mud room and front entrance area [front
   
2. Thermostat 2 [Loop 2,3]
   Open kitchen/living room including stair case to entrance area. [front]
   
3. Thermostat 3 [Loop 4]
   Bathroom 1 and lower hallway [back]
   
4. Thermostat 4 [Loop 5]
   Kids room [back]
   
5. Thermostat 5 [Loop 6]
   Master bedroom and top hallway [front]
   
6. Thermostat 6 [Loop 7]
   Master bathroom [front]
   
7. Thermostat 7 [Loop 8]
   Top Bedroom [back]
   

To the front you enter the house, on that level is only a mudroom. This room is connected to manifold 3. Connecting it to the manifold 2 would have meant to have more 1/2" tubing from the manifold to the actual radiant loop (and back) than runs actually in the boards itself.

You go like 1 level up and be to the front in the combined kitchen/living room. Over this room is the master bath room and bed room. The manifold 1 is located in the master bedroom, as this is the highest room.

To the back you have a small a hallway in the center of the house connecting 4 set of flights to the different leveled rooms.
In the top bedroom which is the highest room of the house there is manifold 2 for all rooms in the back/center of the house.

Different Design Temperatures

I did calculations as commonly referenced with 0F that feels a bit overkill taking the local climate into considerations. The 20F design feels closer to reality of climate and feels not as crazy in regards to sizing requirements. I was looking for validation of that assumption.

Webstone Closed-spaced Tee

Out of curiosity, what is your experience reason for not taking it?

Internal Circulator of the boiler

The Bosch boiler has an internal pump for first circulation loop.

Mixing valve

I guess I over designed it to have a secondary regulator in place in case the boiler's ODR control fails. So I can save that money and added complexity it seems.

hot_rod

A Caleffi Sep 4 would cover 4 functions, clean up the piping, and give you a bit buffer capacity. And it is insulated👍

theoj

HI @hot_rod ,
thanks for the tip, my question would be if a part of the Sep 4 breaks can any part be replaced/repaired or is a total replacement needed? Thx.

hot_rod

yes all the components can be removed and replaced

The only moving or wear part is the hinge and needle valve up top.

The cap can be easily removed and replaced

Zman

I agree with the above comments, ODR does not fail very often. Mixing valves do. Outdoor reset will be perfect for your climate.

It looks like you have the relief valve in the top right corner. It needs to be on the outlet of the boiler as close as possible, with no isolation valve between the boiler and the relief valve. With this design, if someone closed the isolation valves, the boiler would blow...

theoj

HI @Zman , @hot_rod , @Ironman, @STEVEusaPA ,
Thank you so much for your detailed feedback.

I have updated the plan based on the feedback and resulting changes provided.


Does this look to be the right design now?

What did I miss or would need to consider?

Thanks again,
Theo

hot_rod

nice, the distribution circulator could be right at the hydrosep.

Probably a conceptual drawing, limit piping ups and down to minimize air trap potential

theoj

Hi @hot_rod ,
You are absolutely right. That is not an actual layout plan but more the conceptual drawing working with the previous plan as a starting point and doing quick adjustments with the limitation doing it by hand in Power Power .

The real layout have least amount of turns, and close runs is probably closer to this (without the addition turn around the calculation table ):