Multiple temps piping strategy

Wayco Wayne_2

I have a munchkin I'm going to install. A 140M. I have; 1. a snowmelt sidewalk (20,000 btu), 2. A storage shed with radiant floor in slab (3600 btu's 75 degrees water temp needed).
3. 2 rooms with joist trak with linoleum. ( 7000 btu's 120 water temp needed.
4. 3 rooms with joist trak and carpet (13,000 btu's 150 water temps needed
5. A hydro coil for the rest of the house. (35,000 btu's 160 to 180 degrees needed)
6. A future indirect water heater.
7. A future spa heater heat exchanger.
Boy do I need help designing this. All off one Munchkin. Keep it simple and looking good. No problem , right??? All suggestions welcome. I'm trying to keep it reasonable cost wise too. My wife's radar is already producing beeping sounds. (what exactly are you doing down there?). Thanks in advance. WW

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S Davis

Water Temps

With that many water temps you might take a look at the Taco I series valves you can get them in set point and outdoor reset and they are not too pricey, and then set it up primary/secondary.

S Davis


Apex Radiant Heating

hr

any way to

meet the loads with the highest temperature being 145°?

Check your AH output spec at this temperature.

This temperature (145°)should also drive most transfer plate applications. Rare to need over 140-150, in a transfer plate application, which is about max for most plywoods, etc.

Then maybe just one mix down temperature, perhaps a 3 way thermostatic for the linoleum zone. Or a manual 3 way and let it float with the boilers reset temperatures.

I'd run the snowmelt via a HX so you don't have to glycol the whole system. If I am not mistaken HTP doesn't want more than a 35% glycol anyways.

I'd think that 145° on the A side of the HX would probably run the snowmelt just fine if you size, and pump the HX accordingly. Flat Plate design guys can do that sizing for you. By the square footage it doesn't sound like the snowmelt is that critical?

Of course the Vision 1 control will handle the DHW temperature and priority, as well as outdoor reset on the entire package.

No sense making the piping and controls too complicated, IMO

hot rod

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Bill Nye_2

I agree with........

Hot Rod said the same thing I was about to say, saved from typing.

Constantin

This is the cheapest solution I could think of...

... simply stagger the loads, highest temp first and cascade down from there. Using inexpensive TRV valves, you can ensure that no zone ever sees temps in excess of what they're rated for. If everything is properly balanced, constant circulation and one OR sensor for the whole system is a possibility. Flat plate HX's then allow PG-filled loops to the pool and the snow-melt system.

Should make the Munchkin condense like mad. Naturally, a spendier solution (with constant circulation and the like) would be motorized OR-fedback 4-way valves and all that. Not likely to pass the wife test.

Troy_3

Vision 2

Vision 2 will handle up to 32 temps all running on their own curves. Bellimo motorized valves will mix down each individual temp. off the primary loop. The primary temp. is reset according to the greatest load at the time. That way the whole system runs at the lowest temp. possible. This is so trick. And reasonable. Plug in the laptop and watch it all happen.

Wayco Wayne_2

This is all very helpful

and is also driving me mad. I will check the prices on the vision 2 tomorrow, but am cautious of what the price might be. I am using a flat plate for the snow melt and the future spa. The hydro coil does need to be at least 160, but I was thinking of running it off the domestic water cicuit and splitting them with zone valves. I saw the Taco valves at WS4 and will check on them tomorrow also. By the way Troy, Where are you located? I have family in upstate NY and my daughter is at RIT. Are you close to Rochester? WW

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Wayco Wayne_2

Oh yeah!

Should I use a buffer tank? A lot of these zones are pretty small and the 140M only modulates down to 30% as I recall. (38000 btu's) I would have to be running everthing to get full capacity. (126,000) Cold snowy day. WW

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Jamie_6

Wayne,

That is exactly what I was thinking! With a turn down ratio of 5 to 1 and the size of some of those zones it really sounds like you would be short cycling that boiler a lot. I would lean towards a buffer tank and let that tank run off of outdoor reset (via Vision 1). Let the demand on the tank (an aqua-stat) be the only feed back to the boiler. The top of that curve would be your 145 degrees. Then just mix everything else down with mixing valves. This way your entire system runs off of the boiler reset as opposed to a load reset.

Sometimes I think it can get a little crazy when you start incorporating both resets!

Let us know what you decide to do and I would love to see some pictures of the system.

Jamie

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hr

I concur with the buffer

IF there is the potential for small loads to be running very often.

I used a stubby 40 electric for this buffer Munchkin. Ran the boiler at 140° for the transfer plate zones and a 3 way to mix the slab zones.

Now if HTP would hurray up and load the Munchkin burner and control onto the Voyager tank!!!

The tank for radiant zones and the intergral HX for any glycoled loops. And a nice buffer capacity to handle micro zoning. Talk about the ideal radiant heat sourse :)for todays multi/ micro zoned systems.

hot rod

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Boilerpro_3

How I do it

I build a ladder of piping with the supply from the boiler at the left and the return to the boiler at the right. The boiler and this ladder are pumped with its own circ. Each rung is a different temp need and has a balance valve on it.

From these rungs the supplies to the heat emitters are piped P/S with a thermometer on the supply.

The reset controller is set to reset on the highest design water temp and with the steepest curve needed for the system.

The balance valves are adjusted to limit flow through the rung of the lower temp supplies so that the only enough hot water is supplied through the rung to meet the heating supply temp for that need. For the lower temp rungs, the amount of water moving across the rung is less than that circulated through the heat emitters, so return water from each end need is mixed with the supply feeding the end need at the closely spaced tees, running that loop at a lower temp. If you wait a week or so I can show you a picture of the setup.

Boilerpro

jerry scharf_2

I'd vote for the vision 2 as well

WW,

The great thing about the vision 2 is that it will get the most out of your munchkin efficiency-wise. Each water temp gets it's own reset curve. When the air handler isn't calling for heat, the target temp for the boiler is dropped to the requirement of the next hottest demand and so on. So even if at design temp you're not condensing on the air handler, you would still be condensing on all the other loads on design day.

It's a motorized valve setup. I think each V2 box can handle 4 temps, so you may need a couple boxes if you have 5 temps.

jerry

Floyd_7

Boiler Pro's got it.....

I'd do it his way, simple and effective.

floyd

Wayco Wayne_2

Thanks for all the help

I saw the Voyager (in the lab) with the modulating burner on the HTP tour last month. It didn't occur to me until now that if you use it just as a boiler it's like having a built in buffer tank. Way cool! I would like to see the pictures of what you're describing Boilerpro. I've got to make a decision soon. I'm putting a board up on the wall tomorrow. I want to paint a Rembrandt, but am afraid of it turning out to be a Sidney Pollack. Ack!! My system is running off an old Polaris right now, but it has been added to in drips and drabs over the years and looks like crap. I would never leave a customers system looking like mine for sure. Dan Foley visited my Hydronics class last week and told my students how important it is to be organised and to plan things out. I am the most guilty of not planning. I do a heat load on a job and show up with a truck full of equipment and pipe and make it up as I go. I gotta change my ways. Hopefully I can start on my own house. WW

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Jamie_6

Floyd,

THANK YOU for those fittings! Everything is fixed and the tiles are back. I am waiting for our Christmas cards to come in and you will be getting the cash in the mail.

Jamie

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