Radiant Heating Newbie - Guidance Needed

DaveABC

Here is my current plan for radiant heating that I need help with:

I am looking for ways to improve on this design. I am not focusing on the spacing/layout of the parts yet but more so the functionality and concepts. I'm trying to get a good schematic and parts list that fits my needs. Thanks for any help. I've already learned alot and improved on my initial design from the last discussion.

FYI: I have public water, sewer, & gas service

Version 2:



UPDATE:

• No one way valves after zone valves
  
• No one way valve on main loop
  
• zone manifolds kept the same because zone 1 has lowest heat loss, zone 3 has the most (maybe, more calculations needed)
  
• Backflow preventer added on hydronic feed
  

Ironman

Why would you choose a combi and what's your domestic load? What's the but load of each zone?

No check valves should be used with zone valves.

What model Taco? It will have to be a delta P circulator.

Rich_49

Arrange the manifolds so that the furthest from the circ has the highest head loss , declining back toward the circ . This way no matter what combination is calling all will get good flow . I suggest using a Taco VT2218 circ for this application also . Delta set to 10* would be sufficient .

Don't forget a pres. red valve and backflow preventer on the boiler feed . I also suggest utilizing a purge set up on each manifold instead of one for the whole system as shown .

If you must have those one way valves move them to the return side of the manifolds since the zone valves are right there . Get rid of the 1 way valve on the system loop also , it is just redundant .

Does the Navien have an integral boiler circ ? If not , do not forget that in your equipment purchase .

DaveABC

Thanks guys! I'm responding to the response in the blockquote below. I'm thinking of a combi for domestic and heating use. I have no boiler or furnace currently(kerosene, brrrr...). The brochure says it can provide heat and two showers/dishwasher at the same time. Also within heating BTU range. I was sold on the NCB-180E.

I don't know the BTU laod of each zone. I did it for the whole house and may have to calculate when I have more time.

On Version 1:

• Zone 1: Bedroom is upstairs, 278 sqft
  
• Zone 2: Living Room, 205 sqft
  
• Zone 3: Dining/Kitchen, 458 sqft
  

We are also having supplement electric heaters in one 136 sqft room and two bathrooms. We may try to pick up some radiant heat in those rooms on the way to/from the zones.

I do not know what model Taco for the pump, I am still learning. Perhaps a delta P circulator.

Ironman said:

Why would you choose a combi and what's your domestic load? What's the but load of each zone?



No check valves should be used with zone valves.



What model Taco? It will have to be a delta P circulator.

DaveABC

Rich said:

Arrange the manifolds so that the furthest from the circ has the highest head loss , declining back toward the circ . This way no matter what combination is calling all will get good flow . I suggest using a Taco VT2218 circ for this application also . Delta set to 10* would be sufficient .

Don't forget a pres. red valve and backflow preventer on the boiler feed . I also suggest utilizing a purge set up on each manifold instead of one for the whole system as shown .

If you must have those one way valves move them to the return side of the manifolds since the zone valves are right there . Get rid of the 1 way valve on the system loop also , it is just redundant .

Does the Navien have an integral boiler circ ? If not , do not forget that in your equipment purchase .

Thanks for the advice. I added version 2 to my original post. I'm not sure what a pres. red valve is so I'm going to do research on that. It does have an integral boiler circ, I will double check though.

Rich_49

Ironman said:

Why would you choose a combi and what's your domestic load? What's the but load of each zone?



No check valves should be used with zone valves.



What model Taco? It will have to be a delta P circulator.

Why in the world would it have to be a Delta P circ ? This example only has Delta T circs , how is it possibly working without P circs ?

njtommy

The Navien combi is not able to provide heating and DHW demands at the same time. Also do your self a favor and don’t hook up to the makes up water on the boiler it’s self. Pipe it right into the air separator it’s way easier to purge air out of the system there. Also install an air vent and T on top of the boiler to allow you to purge air out of the heat exchanger with out having to pull the relief valve.

DaveABC

njtommy said:

The Navien combi is not able to provide heating and DHW demands at the same time. Also do your self a favor and don’t hook up to the makes up water on the boiler it’s self. Pipe it right into the air separator it’s way easier to purge air out of the system there. Also install an air vent and T on top of the boiler to allow you to purge air out of the heat exchanger with out having to pull the relief valve.

Thanks, I'll have to look into those suggestions. The Navien Combi can provide both at the same time. Here is literature from the information packet:

Ironman

Rich said:

Ironman said:

Why would you choose a combi and what's your domestic load? What's the but load of each zone?



No check valves should be used with zone valves.



What model Taco? It will have to be a delta P circulator.

Why in the world would it have to be a Delta P circ ? This example only has Delta T circs , how is it possibly working without P circs ?

Because when you're 62 and looking at a diagram on your phone without your reading glasses, you miss things like the Taco ZVC.

Rich_49

DaveABC said:

Thanks guys! I'm responding to the response in the blockquote below. I'm thinking of a combi for domestic and heating use. I have no boiler or furnace currently(kerosene, brrrr...). The brochure says it can provide heat and two showers/dishwasher at the same time. Also within heating BTU range. I was sold on the NCB-180E.

I don't know the BTU laod of each zone. I did it for the whole house and may have to calculate when I have more time.

On Version 1:

• Zone 1: Bedroom is upstairs, 278 sqft
  
• Zone 2: Living Room, 205 sqft
  
• Zone 3: Dining/Kitchen, 458 sqft
  

We are also having supplement electric heaters in one 136 sqft room and two bathrooms. We may try to pick up some radiant heat in those rooms on the way to/from the zones.

I do not know what model Taco for the pump, I am still learning. Perhaps a delta P circulator.

Ironman said:

Why would you choose a combi and what's your domestic load? What's the but load of each zone?



No check valves should be used with zone valves.



What model Taco? It will have to be a delta P circulator.

You'll need a room by room heat loss to do the radiant PROPERLY .

Why not just do radiant in those rooms ? After this is done , then and only then can you make sensible zoning decisions . Some guidelines to follow for zoning are
Similar ( =/- 1*F) BTUh per sf output , similar finish floor R value , similar use pattern , similar shading . All these should be met to have rooms on same zone . Example : 2 rooms with same everything where one is on the south side and one on the north side will not behave on a sunny day , if you locate the t stat in the south room , the north room will be cold and vice versa .

Taco VT2218

DaveABC

Okay awesome thanks all! I need to do a more in depth analysis. Check out the mounting wall:

We are not doing the two baths or back room b/c of price and time. We need to do electric, domestic/heat plumbing, data lines, insulation, structural, flooring, you name it. Lots to do before the certificate of occupancy.

I'm using 1/2" pex, 2 per joist bay. Should the wall be copper pipe before the pex? What size piping? I was thinking sharkbite fittings if I can get away with it b/c I've only soldered pipe once. What is a sweat valve? A valve that needs a soldered connection?

So many questions?!

I'll leave it at that for tonight.

Gordy

Beware of the naviens claim of both domestic, and heating load,at the same time. The word simultaneously does not exist in their advertising. Something will starve for btus.

Rich_49

Judging by the size of your rooms you may be better served using 3/8" pex ( O2 barrier) . Please tell us you'll be using extruded plates attached to the subfloor for this and you're not thinking of suspended or plateless install

Gordy

As,rich said you really need to dial in your heat loss numbers room by room before you start, or buy anything.

DaveABC

Rich said:

Judging by the size of your rooms you may be better served using 3/8" pex ( O2 barrier) . Please tell us you'll be using extruded plates attached to the subfloor for this and you're not thinking of suspended or plateless install

We are using aluminum heat transfer plates, air gap, foil type reflective barrier, and insulation. Although plateless for living room b/c some nails in the bottom of the subfloor. Any thoughts on brand of reflective barrier or insulation?

Gordy

Skip the foil barrier over rated. The reflectivity means little once dust settles on it. Put that money tword radiant missing in other rooms. Insulation Roxul.

KC_Jones

The reflective barrier is snake oil don't waste the money. For the living room, cut the nails off and use the plates.

Don't skip any steps do this right, you only have one chance to get it so.

On a none heating note I suggest you curb your excitement/enthusiasm and think this through very carefully. You are getting rock solid advice here I suggest you follow it carefully.

Please please please don't use sharkbites.

Also do the room by room heat loss calculations, no design can be started until you have that information.

My $0.02

Gordy

To cut the nails flush literally spark free use a multi tool with a metal blade zip done.

Rich_49

DaveABC said:

Rich said:

Judging by the size of your rooms you may be better served using 3/8" pex ( O2 barrier) . Please tell us you'll be using extruded plates attached to the subfloor for this and you're not thinking of suspended or plateless install

We are using aluminum heat transfer plates, air gap, foil type reflective barrier, and insulation. Although plateless for living room b/c some nails in the bottom of the subfloor. Any thoughts on brand of reflective barrier or insulation?

Please do not use Ultra Fin or anything like it . Use the plates right to the subfloor and put the insulation up tight to it , NO AIRSPACE !

This will allow you to use the lowest water temps and MAXIMIZE the efficiency of the boiler . You want to heat your house using the coldest water possible . The less a condensing boiler condenses the less efficient it will be

Reflective barrier does not work unless it stays spotless , yough to do with an airspace even in the best conditions . To direct heat energy you NEED Resistance , not shiny stuff . When shint stuff gets dusty and dirty and no longer shiny it is worthless . I am not altogether convinced that shint stuff works without light regardless . Ever look in a mirror in the dark ? they don't work that well .

Gordy

I will also add DONT use the thin beer can plates. Use omega style extruded plates.

Brewbeer

Heat loss calc.!

Ironman

Use a mod/con like the HTP UFT080 or the Lochinvar KHN080 plus an indirect water heater, not a combi. Both have a fire tube heat exchanger and a 10 to 1 turndown. Depending upon what the load is on your smallest zone, you may still need a buffer tank to prevent short cycling.

njtommy

Navien cannot handle both at the same time. I’ve installed several and have one in my own home. 13,000 btus is the lowest modulation for this combi. Beware of small zones. Along with every time you open a sink to wash your hands or do laundry and the washer calls for a little bit of hot/ warm water the boiler shuts down to switch over to handle the DHW load. It’s a lot of stopping and starting on these Combi boilers.

DaveABC

Thanks for all the advice! I'm going to use a 1 3/8" bit to drill the holes in the joists at least 2" from the top, 3" and 8" away from the wall. I could use more help on the insulation plan for the radiant heat. The answers I'm getting are different everywhere. I've heard air gap/no air gap, reflective barrier/no barrier. Any more thoughts?

Gordy

No air gap with plates conduction is the driver in that method. Air gap is for suspended tube where convection is the driver in the heat transfer.

Pay close attention to the rim joist detail for insulation. Xps, and foam in a can to seal.

You won’t find many if any that would use bubble foil in the detail. Roxul is what I would use in the joist bays.

Rich_49

Gordy is correct on all aspects . Leave a 1" space between ends of plates . Make sure full contact is made with sub floor . Roxul stays put best .
Bubble foil does zero as it only provides air space as insulation ( bubbles) , shiny stuff is only as good as how clean it stays and then you have that whole light thing . Air gaps are for suspended tube , Ultra Fin and the like , you know , the least effective ways to do radiant .
Remember to insulate the ends of the joist spaces ( box beam ) on the exterior also prior to putting in your tubing , plates and below tube insulation .

Eastman

Have you considered running the tubing on top of the sub-floor?

Gordy

On top is always y first choice

Paul48

Switching relays control circulators. You need a zone valve control. There must be a primary and a secondary circulator. Just observations