DIY Hydronic Floor Heating - Page 48

Mikesolar · 02-14-15, 03:54 PM

OK, here is what I would do. First: how many of the walls are cold walls? If, for example, you are adding an addition onto the back of a house (sorry if I cannot remember the details of you place, assuming you sent a layout), you will have 3 cold walls. Knowing you have 2 loops, Loop 1 will start at one end of the manifold, go along one cold wall, to the corner (32') then turn and do 8' of the 16' wall, 180deg and back to the start of the cold wall. (an "L" shape). Keep doing this till you have just enough tubing left to get back to the manifold. Do not worry where the last 180deg turn ends up, the next loop will start from there.

Loop 2 follows the last tail of loop one to the cold wall. Repeat the above procedure. The 2 L patterns will be mirror images (almost) and the tubing will be correct at the manifold. There will be only one tube not in the right place and its temp will blend in with the rest.

Drake · 02-14-15, 05:42 PM

Though my new addition is attached to existing cabin the I am treating the new space as a separated zoned space as a winter core for heating so all walls except one short one will be cold. The long south(mostly window and North wall will be coldest. So my layout design is very much as you describe only with one more leg. Making a "U" instead of an "L" along walls serpentining to center than back to manifold. NO crossing. The two 16x16 200' "U" loop open ends face each other at the center of the 16x36(2' of cabinet work at both ends make exposed floor 16x32). The can pex cross question has been retired.

Mikesolar · 02-14-15, 05:45 PM

Excellent. That would be the next thing I would have suggested.

buffalobillpatrick · 02-14-15, 07:52 PM

OD of 1/2" pex = .625"

Drake · 02-15-15, 09:50 AM

I am also confident that this pattern will distribute passive solar gain in the area of solar exposure to through out slab increasing it ability to hold more thermal storage and even out heating by circulating loop even when heat is not needed. I wired a fan override switch into my thermostat on my current homes furnace to use fan to circulate air when I don't want to heat(often run fan only in summer), can something like that be done with a circulating pump to be another option to circulating only when heating or continuous flow?

Though crossing pex is no longer in my layout even .625/1.5" is still a higher pex to cement ratio than 2x.625/4" and with extra reinforcing maybe even fiberglass additive in cement structural cracking could be adequately resolved if possible cracking is the significant reason not to cross pex within a slab. As the slab of my radiant floor is a suspended 1st floor over basement it will already be over engineered/reinforced for my own peace of mind.

buffalobillpatrick · 02-15-15, 12:34 PM

Yes, Solar distribution to cooler areas of house is a good idea.
Constant circulation in Winter (common in Euro) provides the best even heating vs. what is called Bang/bang on/off of pumps, (common in USA), but it uses more electricity$.

Boiler, etc. heat can be injected into a zone that uses constant or semi-constant circulation (Grundfos Alpha would be great) with a small low power injection pump into "close T's". A pump only has to overcome the resistance that it see's. A 10-15W injection pump could be enough.

I did it this way in a neighbors house that has huge solar gain from LARGE West facing wall of glass, views of mountains. 9 zones, about 4,500ft2 Hickory floors over 1.5" concrete with 2x4 sleepers every foot.

Drake · 02-15-15, 01:01 PM

I will be utilizing an ejection value in the closed system I'm planning as I just got a super deal on a brand new 85gl REEM Marathon elec water heater $500. As I only have 600' total of pex to feed to heat a 1100 sq'(story and 3/4) super insulated space(R45walls,
R70ceiling) I should be easily able to off peak heat the tank. Wish I could have got two at that price to use the other for DHW.

Drake · 02-15-15, 01:17 PM

There is a Grundfos cir pump on clearance at my Menards will have to check it out more. It was marked composite instead of cast iron or SS.

buffalobillpatrick · 02-15-15, 03:25 PM

"ejection value" ? Zone valve?

Buy 1200' more O2 barrier pex & install on 8" centers, this will allow about 20*F cooler feed temperature than 18" OC. with much less "stripping" hot & cold areas.

Without O2 barrier pex all components that touch water must be SS, brass, or composite.

Will new Marathon supply hot water to floor & DHW? If so what is it's tank liner PEX?

Grundfos makes great pumps, composite should be fine.

Drake · 02-15-15, 03:51 PM

Sorry injection valve or mixer valve. 1st floor twin loops in 16x32 area measure out to approx 230' ea with the first three passes around exterior at 9" the rest at 12" on graph paper. Nothing is 18"cc. The second floor is open to below and over half storage space that won't require heating but will be warm enough by just heat bleed. We require very little hot water so hydronic system and DHW will be separate for now. The reason I like the hydronic radiant method to heat is that heating the fluid can be done many ways and can be modified at will.

02-14-15, 03:54 PM	#471
Mikesolar Master EcoRenovator Join Date: Aug 2012 Location: Toronto Posts: 958 Thanks: 40 Thanked 158 Times in 150 Posts	OK, here is what I would do. First: how many of the walls are cold walls? If, for example, you are adding an addition onto the back of a house (sorry if I cannot remember the details of you place, assuming you sent a layout), you will have 3 cold walls. Knowing you have 2 loops, Loop 1 will start at one end of the manifold, go along one cold wall, to the corner (32') then turn and do 8' of the 16' wall, 180deg and back to the start of the cold wall. (an "L" shape). Keep doing this till you have just enough tubing left to get back to the manifold. Do not worry where the last 180deg turn ends up, the next loop will start from there. Loop 2 follows the last tail of loop one to the cold wall. Repeat the above procedure. The 2 L patterns will be mirror images (almost) and the tubing will be correct at the manifold. There will be only one tube not in the right place and its temp will blend in with the rest.

02-14-15, 05:42 PM	#472
Drake DIY Guy Join Date: Jan 2011 Location: Mpls,MN Posts: 315 Thanks: 2 Thanked 17 Times in 17 Posts	Though my new addition is attached to existing cabin the I am treating the new space as a separated zoned space as a winter core for heating so all walls except one short one will be cold. The long south(mostly window and North wall will be coldest. So my layout design is very much as you describe only with one more leg. Making a "U" instead of an "L" along walls serpentining to center than back to manifold. NO crossing. The two 16x16 200' "U" loop open ends face each other at the center of the 16x36(2' of cabinet work at both ends make exposed floor 16x32). The can pex cross question has been retired.

02-14-15, 05:45 PM	#473
Mikesolar Master EcoRenovator Join Date: Aug 2012 Location: Toronto Posts: 958 Thanks: 40 Thanked 158 Times in 150 Posts	Excellent. That would be the next thing I would have suggested.

02-14-15, 07:52 PM	#474
buffalobillpatrick Master EcoRenovator Join Date: Mar 2014 Location: Florissant, Colorado Posts: 599 Thanks: 814 Thanked 59 Times in 55 Posts	OD of 1/2" pex = .625"

02-15-15, 09:50 AM	#475
Drake DIY Guy Join Date: Jan 2011 Location: Mpls,MN Posts: 315 Thanks: 2 Thanked 17 Times in 17 Posts	I am also confident that this pattern will distribute passive solar gain in the area of solar exposure to through out slab increasing it ability to hold more thermal storage and even out heating by circulating loop even when heat is not needed. I wired a fan override switch into my thermostat on my current homes furnace to use fan to circulate air when I don't want to heat(often run fan only in summer), can something like that be done with a circulating pump to be another option to circulating only when heating or continuous flow? Though crossing pex is no longer in my layout even .625/1.5" is still a higher pex to cement ratio than 2x.625/4" and with extra reinforcing maybe even fiberglass additive in cement structural cracking could be adequately resolved if possible cracking is the significant reason not to cross pex within a slab. As the slab of my radiant floor is a suspended 1st floor over basement it will already be over engineered/reinforced for my own peace of mind.

02-15-15, 12:34 PM	#476
buffalobillpatrick Master EcoRenovator Join Date: Mar 2014 Location: Florissant, Colorado Posts: 599 Thanks: 814 Thanked 59 Times in 55 Posts	Yes, Solar distribution to cooler areas of house is a good idea. Constant circulation in Winter (common in Euro) provides the best even heating vs. what is called Bang/bang on/off of pumps, (common in USA), but it uses more electricity$. Boiler, etc. heat can be injected into a zone that uses constant or semi-constant circulation (Grundfos Alpha would be great) with a small low power injection pump into "close T's". A pump only has to overcome the resistance that it see's. A 10-15W injection pump could be enough. I did it this way in a neighbors house that has huge solar gain from LARGE West facing wall of glass, views of mountains. 9 zones, about 4,500ft2 Hickory floors over 1.5" concrete with 2x4 sleepers every foot.

02-15-15, 01:01 PM	#477
Drake DIY Guy Join Date: Jan 2011 Location: Mpls,MN Posts: 315 Thanks: 2 Thanked 17 Times in 17 Posts	I will be utilizing an ejection value in the closed system I'm planning as I just got a super deal on a brand new 85gl REEM Marathon elec water heater $500. As I only have 600' total of pex to feed to heat a 1100 sq'(story and 3/4) super insulated space(R45walls, R70ceiling) I should be easily able to off peak heat the tank. Wish I could have got two at that price to use the other for DHW.

02-15-15, 01:17 PM	#478
Drake DIY Guy Join Date: Jan 2011 Location: Mpls,MN Posts: 315 Thanks: 2 Thanked 17 Times in 17 Posts	There is a Grundfos cir pump on clearance at my Menards will have to check it out more. It was marked composite instead of cast iron or SS.

02-15-15, 03:25 PM	#479
buffalobillpatrick Master EcoRenovator Join Date: Mar 2014 Location: Florissant, Colorado Posts: 599 Thanks: 814 Thanked 59 Times in 55 Posts	"ejection value" ? Zone valve? Buy 1200' more O2 barrier pex & install on 8" centers, this will allow about 20*F cooler feed temperature than 18" OC. with much less "stripping" hot & cold areas. Without O2 barrier pex all components that touch water must be SS, brass, or composite. Will new Marathon supply hot water to floor & DHW? If so what is it's tank liner PEX? Grundfos makes great pumps, composite should be fine.

02-15-15, 03:51 PM	#480
Drake DIY Guy Join Date: Jan 2011 Location: Mpls,MN Posts: 315 Thanks: 2 Thanked 17 Times in 17 Posts	Sorry injection valve or mixer valve. 1st floor twin loops in 16x32 area measure out to approx 230' ea with the first three passes around exterior at 9" the rest at 12" on graph paper. Nothing is 18"cc. The second floor is open to below and over half storage space that won't require heating but will be warm enough by just heat bleed. We require very little hot water so hydronic system and DHW will be separate for now. The reason I like the hydronic radiant method to heat is that heating the fluid can be done many ways and can be modified at will.