Caleffi manifolds EDIT: When you don't know what you don't know :)

skyking1

I am building new with in slab pex, staple up, and an air handler for those few weeks of air conditioning. The air handler can also supplement the radiant heating.

The heat source is a GSHP from horizontal loops.

I have looked at several options for manifolds and loop valving and the Caleffi twistflow manifolds with the standard thermoelectric actuators seem to be a solid product.

Are there any other suggestions for that part of the hardware?

Ironman

You find any better than Caleffi and that’s reflected in the cost.

We have used the Watts/Rehau for several years as well as Uponor with good results.

skyking1

Thank you. I started out with the concept of zone = pump and then quickly got that out of my head. Too many zones. One idea I had was a dedicated towel warmer loop that would be the last thing to shut down as the weather warmed up. That one would have it's own small pump and timer system so you'd have warm towels in the morning and then it would mercifully stop heating the room.

I used the 'ironman' handle for CB radio for a brief moment in time in my youth. :)

ILikeEmOlder

Caleffi has radiant manifolds with an included pump; the price is very competitive. Maybe one of these for your staple-up.

Ironman

Put a thermostatic radiator valve on the towel warmer and forget the complicated timer setup.

But beware: a micro zone like that can short cycle a mod/con boiler to death unless you use a buffer tank.

skyking1

https://forum.heatinghelp.com/discussion/comment/1852300#Comment_1852300

Thanks I will clarify the rest of the install. Those are mixing units with the included pump: I have a low temperature Ground Source Heat Pump as a source and will not be mixing. The lower you can operate one of those, the more efficient the COP will be.

It is coming with a 14 gallon buffer tank and an air handling unit. I ran my own manual J on my house design a few years ago with CoolCalc at Lennox, then last year I paid for a professional asessment and design. The design proved out what I had planned to do with the ducting. It is only for my air conditioning, but the system will heat the house without the hydronics running.

The engineer I hired does not do hydronic design. I am doing that myself.

I installed all the ductwork trunks through my joists as I built. Now I am at the staple up point. I I will get that in, covered for an air gap, and insulated with a 4" batt. I will leave out where needed for plumbing.

https://forum.heatinghelp.com/discussion/comment/1852305#Comment_1852305

I was hoping to run a small pump on a few hour's timer a day out of the buffer would not be too bad.

We're talking about those summer months that don't want any floor heat, specifically the shoulders where you are not running the AC. Once the AC comes on, to heck with warm towels!

I am in the exploration part of this phase and I really appreciate your inputs.

My plan is to heat the house via only hydronics as long as possible, and add some of that air handler heat on the worst few days.

THe manual J:

Total Heating Required Including Ventilation Air: 31	091 Btuh 31.091 MBH
Total Sensible Gain: 25	801 Btuh 94 %
Total Latent Gain: 1	642 Btuh 6 %
Total Cooling Required Including Ventilation Air: 27	443 Btuh 2.29 Tons (Based On Sensible + Latent)

I have a 4 ton inverter pump coming.

I over-looped with 3500' of horizontal loops that are home runs to the equipment room.

I can run half the field at a time and alternate on a schedule and keep those inlet loop temperatures as high as possible, until the real cold SHTF and I can run the whole thing if needed.

That may be impractical but I will figure that out with experience. I know that over-looped is a good place to be. My brother's system was under-looped and his temps got pretty cold in the winter.

skyking1

I-joists are 16" OC and I will put up two runs per bay, using extruded aluminum shields and a narrow crown stapler.

I purchased 500' rolls of 1/2" legendflex tubing, and plan on splitting them into two loops. I'll adjust those lengths to work different areas, but right around 200' outbound is what I am shooting for.

As we work across the house I plan on insulating the transport part of the loop on the way out to the areas to be heated.

I came up with 20 loops, counting the 6 in the concrete.

@0.5 gpm per loop, that lines up with the 4 ton GSHP specs of 9~11GPM.

mattmia2

you would just want to run an odr curve that matched the load and run all of it instead of trying to zone parts of zones. ideally you get the swt temp to match the load and it just runs continuously, the thermostat is just to prevent overheating rather than the operating control.

hydroair coils have to be very big and air velocities low for forced air heating with low water temps. if you feel low temp air moving it will feel drafty and the energy transfer isn't great at a small delta t between the air and water so the coil needs a lot of surface area. unless you can make a sw close to traditional temps just for the hydroair I don't know that i would use that as a strategy for design day conditions.

skyking1

Thank you Matt, that makes sense. Rather than valve control loops just throttle them down to get comfort where I need it?

The flooring is going to have an 85 F limitation, so I am aiming for 105F maximum supply water.

skyking1

@mattmia2 I will wait for the hardware to get here sometime mid-June. I think all is there for implementing ODR control. I see heat set compensation in the documentation, but need to confirm it indeed has the outdoor sensor input required.

If not I will be looking for help with an external unit from supplyhouse.

skyking1

https://forum.heatinghelp.com/discussion/comment/1852461#Comment_1852461

When I don't know what I don't know:

Thanks Matt. I have done the deep dive on your post and it makes sense.

So much so that I can and may go with a larger air handler because I can. I had a 3.5 ton unit ordered, but I called and I can just about double the coil size by opting for the 6 ton unit. Incidentally it comes standard with auxilliary electric heating coils. I had no intention of backup heat but this might prove to be the best possible situation in a bitter cold snap.

The other thought was putting a mixing valve ahead of the hydronics, and turning up the SWT to a level where the air handler works as intended, only in the extreme end of the curve. You planted a lot of seed and I am grateful for all your knowledge.

Now I am looking at other manifolds based on feature set. They all seem to have provisions for adding a zone control actuator, but the Legend units have some easily manually operated valves on the return side that you can just turn.

That could come in handy on the south rooms that are going to bake. Go shut those loops off when you want to enjoy the insolation, and still keep some warm floors on the north side.

hot_rod

Pretty much any manifold that accepts actuators and also has flow meters give you two way to shut off, or balance flow.

On the actuator side you can adjust with the white plastic knob. Also on the flow indicators you twist them to adjust flow.

If you keep the fluid clear you can observe flow in the clear plastic indicators.

Some pics of the cut away to see those valves.