2 floors of radiant w/ 1 manifold?

Jamie_6

I'm looking @ a job that will have a 4" thick concrete pad on the first floor & a 1 1/2" gypcrete floor on the second floor! I would like to use 1 manifold w/ zone valve actuators on them for each floor. (Since I can give both floors the same temp; they will have the same floor covering also) I just wanted to know if anyone has done something like this and if it worked OK? Or if anyone could think of any pros or cons for doing this?


Pompetti Heating & Air Conditioning, Inc.

www.PompettiHVAC.com

kevin

how about your...

loop lengths? will they about equal? you could use 1 temp and have two seperate manifolds if the temp is your only concern. Two drastically different set of lengths might give you some responce time issues....kpc

Paul_6

Yea, and i was thinking

the differance in thermal mass might cause a response time issue. Paul

Jamie_6

Both rooms are idetical, one right on top the other (even the floor coverings will be the same). I can use the same tubing lay-out for both. What do you think?

Pompetti Heating & Air Conditioning, Inc.

www.PompettiHVAC.com

Jamie_6

Paul, I was thinking the same thing! But if I use the zone-valves do you really think it matters if the second floor satisfies faster then the first?

Pompetti Heating & Air Conditioning, Inc.
www.PompettiHVAC.com

Mike T., Swampeast MO

Assuming tube at bottom of slab and gyp:

The gyp will have an R-value about 3 times higher than the concrete. (Actual numbers depend on tube spacing but proportion stays quite similar.)

BUT if slab-on-grade there is always some downward loss and certainly edge loss BUT the gyp (by virtue of having its backside essentially in the conditioned envelope, little edge loss and the tendency of warm air to rise) I'd guess that given identical construction (particularly windows) that the two would respond quite similarly.

If above situation is correct you [should] be OK using the same temp and identical run lengths. Of course it's always a good idea to tighten spacing at the edge of a slab on grade and loosen it a bit towards the middle...

eleft_4

Jamie,
You can control the flow on each panel to equalize the deltaT.

al

hot_rod

Your heatloss calc

and design should answer all these questions. What are the temperature requirements according to the design. If they are within 10-15 degrees of one another, 1 mix temperature would be fine.

Also, depending on the number of loops you may want two manifolds with zone valves or pumps. To me it gets weird seeing 10 or more telestats controlling two zones, expensive too.

hot rod

Tom Meyer

The original question...

If I got it right, your original question was can you use one manifold for both floors or should you use two?

Manifolds are determined primarily by delivery water temperature to the individual loops. If you're within 10 deg on all your loops you should be able to use a single manifold.

The next consideration is the length of runs and number of loops. Would it make more sense to run a single manifold supply and return to the second floor manifold or run the loops individually to and from the second floor.

You can zone the floors using tstats to the individual loop valves and use balancing valves to adjust. I would recommend using at least two tstats to account for any response time issues.


Senior Designer/Trainer
Precision Hydronics Corporation
www.precisionhydronics.com

Wayco Wayne_2

Hey Jamie

I agree with everyone else but would like to add that a PID thermostat controlling the telestats might help to make up for the difference in thermal mass. (BTW, was talking to your man over at the Danfoss seminar. Nice to know there's wetheds in the area.) :)WW

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Jamie_6

Thanks for the reply Wayne! But, what are the PID thermostats?

That was Nick, he's the young buck of us all. If you hit our web sight and look @ the second radiant board that's his baby. Not bad for 21! He said he liked the class and the panals! They seem a little $ but I will have to use one to see if it levels out with time!

Pompetti Heating & Air Conditioning, Inc.
www.PompettiHVAC.com

Ted_5

Take a look at Heatlink

Jamie Heatlink has PID stats and controls and a manifold
that can down feed and up feed all in one. You also can
use thier heatloos program and it will give you the valve
setting on each loop for proper flow and temp. Check it out!
www.heatlink.com

Ted

Wayco Wayne

Hey Jamie

PID tstats are electronic tstats with incredible anticipation capabilities. I was once in a class where John Seigenthal(sp?) described how they worked. Not much penetrated my thick skull or was absorbed, but the message my inner caveman took away was, "PID good", "mercury bulb bad." (beer good, water bad) Perhaps a call to Tek mar would connect you to a source of information more technical than that. I'll have a look at your web site. The Danfoss panels are pricey but I think on a large job they would be an incredible time saver. Their solder joints are perfect and a thing of beauty, mine are acceptable.

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