Mod Con boiler supply temps when run with baseboard or radiators

bmwpowere36m3

hot rod said:

With a home run system use a nice radiant manifold. The rads with TRVs pipe to the manifold, not needing actuators.

The bathroom zone I would use a dual stat that measures air and floor temperature. That wires to an actuator on the manifold.

Purchase the manifold with a couple extra ports, you may want to add additional components, towel bars, radiant art, etc.

A delta P circ would be best for this type of zoned system, a perfect match for TRV systems.

Does the manifold need a flow setter/valve? I know Buderus panels have a intergral flow setter and the TRV threads into.

So I don't need to bypass right? Either with a fitting at the radiator or a differntial bypass at the manifold.

Right on!

Any recommendations on manifolds? I was thinking of getting panels from Hydronic Alternatives (pricing seems good) and supposedly they have manifold as well. I'll need to check with them as far as the specifics.

hot_rod

The TRV is a non-electric, thermostatically operated, proportional valve, it will adjust the flow.

Correct most of the valves installed on panel rads have adjustability. Same with flow adjustment at the manifold.

I'm partial to one brand of manifolds, as I do work for a manufacturer.

I like manifolds with features like flow balance and indicators, vents, purge cocks and isolation valves. Pre-mounted on a staggered bracket is a nice feature.

No need for the pressure bypass with a delta P circ, it's an option anyways.

Rich_49

Must have bypass for constant circulation . All could be satisfied at once

bmwpowere36m3

Rich said:

Must have bypass for constant circulation . All could be satisfied at once

So a grundfos alpha can't be dead-headed? However if the ODR curve is set right, presumably it should be constant circ, right?

bmwpowere36m3

hot rod said:

The TRV is a non-electric, thermostatically operated, proportional valve, it will adjust the flow.

Correct most of the valves installed on panel rads have adjustability. Same with flow adjustment at the manifold.

I'm partial to one brand of manifolds, as I do work for a manufacturer.

I like manifolds with features like flow balance and indicators, vents, purge cocks and isolation valves. Pre-mounted on a staggered bracket is a nice feature.

No need for the pressure bypass with a delta P circ, it's an option anyways.

Caleffi manifolds, right?

I was going to ask opinions on Mr.Pex, Viega, Upnor, Viega, Rifeng manifolds.

I was looking at Heatlines for dianorm panels and they carry a "maxifold" manifold.

I will note, that all my PEX lines will drop down from the ceiling (basement), emitters on first floor. I prefer to run the manifold upside down so the pex drops right in and I don't have to make "u" bends or 90s.

Any issues running them (manifolds) upside down?

Hydronic Alternatives also sells a manifold, but I didn't inquire more about it. As far as panels, they seem to have very reasonable prices. I still need to get a quote from Heatlines.

Rich_49

If you use Caleffi manifolds just make sure you turn the ends 180* , air eliminators work better right side up . Not sure how much air will get to them though passing by all the lines first . Maybe you would consider vertical install ?

bmwpowere36m3

Rich said:

If you use Caleffi manifolds just make sure you turn the ends 180* , air eliminators work better right side up . Not sure how much air will get to them though passing by all the lines first . Maybe you would consider vertical install ?

Isn't that no different than the pex coming from the floor (up to the manifold).... water runs past all the supply loops before reaching the air separators?

I don't see there benefit anyway really, if you have a dedicated air separation device. To me it just seems like a "gadget" and maybe eases the initially purging of individual loops.

bmwpowere36m3

On another note, Monday I'm getting an energy audit... so that'll answer my infiltration question.

Steve Thompson (Taco)

No need for a by-pass when using a delta P circ???

CAUTION: If they (delta P or delta T) are set on constant speed (or any setting that doesn't substantially lower the speed with load or flow reduction) the wattage might remain high enough to heat up the fluid in the rotor can.

If the elevated heat in the rotor does not leave the circ (AKA dead heading) it may flash into steam - potentially causing the water lubricated sleeve bearings to run dry and fail. At the very least the life of the circ will be reduced as the bearings will expand if real hot - expansion will cause bearing drag...

Short recommendation - constant speed must have a by-pass (or not be allowed to run during periods of no flow). System reactive circs should be OK without - however if there is a very long run using a by-pass might be a consideration to enable the system to react faster after a long period of being off.

bmwpowere36m3

Steve Thompson (Taco) said:

No need for a by-pass when using a delta P circ???

CAUTION: If they (delta P or delta T) are set on constant speed (or any setting that doesn't substantially lower the speed with load or flow reduction) the wattage might remain high enough to heat up the fluid in the rotor can.

If the elevated heat in the rotor does not leave the circ (AKA dead heading) it may flash into steam - potentially causing the water lubricated sleeve bearings to run dry and fail. At the very least the life of the circ will be reduced as the bearings will expand if real hot - expansion will cause bearing drag...

Short recommendation - constant speed must have a by-pass (or not be allowed to run during periods of no flow). System reactive circs should be OK without - however if there is a very long run using a by-pass might be a consideration to enable the system to react faster after a long period of being off.

I assume you set the Grundfos to run at constant pressure (in the situtation of panel TRVs and a radiant manifold), so as loads change it adjusts its speed... however I don't think it ever drops to 0 RPM if the pressure is too high (maybe).

Conflicting statements when you search the forum for answers.

hot_rod

bmwpowere36m3 said:

Rich said:

If you use Caleffi manifolds just make sure you turn the ends 180* , air eliminators work better right side up . Not sure how much air will get to them though passing by all the lines first . Maybe you would consider vertical install ?

Isn't that no different than the pex coming from the floor (up to the manifold).... water runs past all the supply loops before reaching the air separators?

I don't see there benefit anyway really, if you have a dedicated air separation device. To me it just seems like a "gadget" and maybe eases the initially purging of individual loops.

Air vents on the manifold as sometimes they are installed as, and at the highest point in a system, an upstairs closet perhaps with all the loops going down. It's just good practice to have a float type vent at the highest point, it will catch any air that rises up, generally when the system is not flowing.

All the manifolds can be ordered as inverted mounting and they get built with the air vents facing the correct direction.

Another note, those air vents have hygroscopic caps, so if you want to air test, use the plastic caps they ship with to seal off the air vents.

Hygroscopic caps give you a second level of shut off protection should something jam the float, or stick in the needle valve inside.

hot_rod

Steve Thompson (Taco) said:

No need for a by-pass when using a delta P circ???

CAUTION: If they (delta P or delta T) are set on constant speed (or any setting that doesn't substantially lower the speed with load or flow reduction) the wattage might remain high enough to heat up the fluid in the rotor can.

If the elevated heat in the rotor does not leave the circ (AKA dead heading) it may flash into steam - potentially causing the water lubricated sleeve bearings to run dry and fail. At the very least the life of the circ will be reduced as the bearings will expand if real hot - expansion will cause bearing drag...

Short recommendation - constant speed must have a by-pass (or not be allowed to run during periods of no flow). System reactive circs should be OK without - however if there is a very long run using a by-pass might be a consideration to enable the system to react faster after a long period of being off.

Good catch Steve, if the circ is placed in a fixed speed mode, a bypass is needed. Install a stand alone one at the pump, or use a manifold with one built in.

I prefer it at the circ near the boiler, no need to circulate all thru the system just to bypass.

If it just a high efficiency ECM, adjustable, but fixed speed circ you want or need, look at the B&G Vario. Great circ, great price, no bells and whistles.

SWEI

bmwpowere36m3 said:

How does running 3/8" PEX (o2 barrier) with heat transfer plates, 8" OC sound? Loop-length limited to 200'?

Great, but I'd limit the loops to more like 160' if practical.

bmwpowere36m3

So I got the blower door test completed today...

1670 CFM @ -50 pascals, ACH50 of 4.8-9.6 depending if I include the basement (1300 sqft each).

At the moment the house has no mechanical ventilation, no finished flooring (only subfloor with gaps between sheets), drywall hung and taped, no electrical trim (switches/recep), no recessed light trims and no glass door for chimney (only damper). When the blower was running I could feel quite a bit of air coming in from the recessed lights, around the fireplace masonry (façade torn down) and any subfloor gaps/penetrations. Whereas the windows, doors, electrical boxes, drywall seams were good.

I’m surprised its this low given that a lot of trim work and flooring still need to go in. Per Energy Star guide, the local correction factor is ~19, so 0.25-0.51 ACH!

Rich_49

Mystery solved ! No guessing now , just knowing . Did the rater give you that conversion ?

bmwpowere36m3

Rich said:

Mystery solved ! No guessing now , just knowing . Did the rater give you that conversion ?

No, all I got from him was 1670 CFM… he is supposed to email me a report later.

The 19 conversion factor is from here: https://www.energystar.gov/ia/home_improvement/home_sealing/ES_HS_Spec_v1_0b.pdf

Zone 2, average exposure, 1 story.

Rich_49

So , you did your homework . Cool , that's the number right as the rater mills teach it .

bmwpowere36m3

Rich said:

So , you did your homework . Cool , that's the number right as the rater mills teach it .

I guess the question still remains if I include the basement volume or not... for the heat loss I think I'll just stick with 0.5 ACH to be conservative.

icesailor

"" When the blower was running I could feel quite a bit of air coming in from the recessed lights, around the fireplace masonry (façade torn down) and any subfloor gaps/penetrations. ""

The problem with some "Blower Door" Tests is that they negatively pressurize the house to do the test. In the life of the world, REAL, the house is Pressurized, and the outside moving air is a lower pressure. (Moving air has a higher pressure than flowing air)

I know from multiple experiences how much heated air can be lost through recessed can lights. Even the air tight ones. Unless it is as tight as a crabs @$$ (watertight), and you can fill it up with water and it doesn't leak, you will be connecting a big vacuum cleaner to the house and sucking the heat out of the house.

Want another example? Look at roofs after a light snowfall. When it gets close to 32 degrees, you can see where all the rafters are because of the rafter snow lines where the snow hasn't melted over the more resistive wood rafters. The spaces between the rafters will have the snow melted. On "Cape" style houses with a finished second floor, you can see where the stairs go up to the second floor, and where the knee wall slants are.

Why houses blow up in tornados, and why you open windows on the lee side of a house in a Hurricane or heavy wind storm. To equalize the inside pressure with the outside pressure, The house blows OUT from the high pressure inside.

Rich_49

What are you talking about Ice ? ALL blower door tests take a house to -50Pa . That's how it is done . The pressure differences between out and in are factored into the numbers at time of test due to sensors placed inside and outside reading real time conditions . the math and technology are solid .
There is no other way to see where the leaks are in the house unless you pressurize the house and locate them from the outside .
Rafters and the like that you mention are not leaks they are thermal bridging and a totally different problem . See advanced framing details and other wall assemblies .
simple fact is R value above 13 starts to flatline , whereas ACH (air sealing) or infiltration can lower your BTU requirements at a rate that shocks most .
In the life of the real world all houses hould have balanced ventilation at a proper rate to have indoor environmental quality . Any idea how you find out that rate ? A BLOWER DOOR TEST !
In a hurricane or Tornado none of us are thinking about heat loss as much as survival . Should we make all houses leaky to survive these things or open the window as you state ?

icesailor

@rich:

I know that. All I'm saying is that the actual flow is from inside to outside. Not from outside to inside. Unless you leave a window open. The OP found it when he noticed the air coming out of the can light. I personally found it when I took a candle and it sucked the candle out. In a room that was 62 degrees that wouldn't go any higher, it was 34 degrees inside the can lights inside of a cathedral ceiling. Put a smoke generator up to a can light and see the smoke go inside. My Florida Condo wouldn't cool because of can lights. It was well over 100 degrees inside the lights but 82 at the ceilings when the attic was over 130 degrees from the sun. The insulation companies have special insulated caps for can lights.

I really don't care what the "experts" say. In the real world, the air/heat loss in the cold is the other way. They can make all the adjustments and corrections to any formula they like. In the real word, electrical fixture manufactures will threaten to sue you if you insinuated that their "airtight" light fixtures could be a cause of heat loss in a building.

When you do a major kitchen renovation in a multimillion dollar house, and they install 30+ can lights into a ceiling, and you(I) have designed the space for a certain amount of more than adequate heat, and when it is 16 degrees out and the room is 72 degrees, and a week later, it is 32 degrees out and blowing 40MPH and gusting over 60 MPH but the room won't go over 58 degrees, you better be able to understand and figure out why it is happening. Because the owner is an engineer and the Electrician has already told the owner that his 30+ can lights are all rated to not leak air. But upon further investigation by myself, only 14 cans were air-proof. And that was no guarantee that they weren't totally tight. They weren't designed that way.

The real cause of that particular ship passing was that they had built a big flat deck over the kitchen. The builder made these big huge soffit vents that let massive amounts of cold air flow over the kitchen ceilings. Blocking off the soffit vent, vent holes during the winter stopped the problem and the room would go to 70 at any temperature that the building saw. If the "Blower Door Guy" was called to look for the problem, he would have blamed it on me and claimed that I hadn't put enough radiation in the room. I had installed 30% more radiation in the same room that had worked for 70 years. Everyone swore up and down that there was no heat loss though ceiling lights. BS.

I used to see a ton of Designers nocturnal emission dreams with recessed lights everywhere. With the heat being done by Airhead Contractors. I just laughed when I heard their problems. And they had problems.

Here's something I just thought of but didn't at the time. If I'd taken a 8 1/2" X 11" sheet of 20# copy paper. I'll bet it would stick to the light rim in a heavy windstorm. I'll bet the blower door expert never tried that. Every time it gets really cold, and someone comes here with a cold house, my heart goes out to them. No one understands air leakage or air flow like an old wind chaser.

Rich_49

What i am saying Ice is that knowing the actual ACH nat that can be designed for . You do get that right ? It does not matter what temp it is or wjere you are , the blower door is accurate . Now instead of basing ACH nat on some fictional number you can enter the correct number along with ERV make up and the like and be dead nuts ! Only a blower door test can achieve this level of accuracy . It is a tool that has allowed me at least to design better systems without the calls for service and the need to point out other trades defects .
By the way , I don't give a Rats A$$ about can lights attorneys . In a court of law they would lose as Blower door tests are the recognized test by every efficiency program in this country and others at determining where the leaks are . lawyer be damned , facts are facts . the only thing left for them to do is hold out payment of the claim .

bmwpowere36m3

@icesailor

The recessed lights are all Halo IC & air-tite rated cans. They have a foam gasket that sits against the drywall and another were the BX penetrates the can. I totally agree they are not 100% air tight, but much better than other recessed cans. The insulation is packed around the lights....

It's important to note that I had NO trim/baffles installed and I plan to put in LED retrofits with an integrated baffle/trim. They also incorporate a gasket to seal them to the drywall.



Anyway back on topic…

I think I’ll start a new thread, but I have questions regarding P/S piping, pex pipe selection and other system details.