TRV's with Radiant floor....Boilerpro

Boilerpro_3

Wonder if any of you have tried this. I'm concerned that as the flow throttles down that the floor would cool off at the end of the tubing loop, creating less than quality comfort. I expect that that the zones would tend to be throttled down when unoccuppied, so comfort is not an issue, but it could happen when there's lots of people in the room or a sunny day, too. I think it might work with a tight outdoor reset curve, but would like your input.

Thanks again, All!

Boilerpro

ScottMP

Is this in the same room ?

I would not run it off the floor loop. ME has done some where he uses the trv for supplemental and it tempers itselve. I have done some where we used the panel as second stage with a thermostat. I would be concerned about it coming off the floor.

If you have a manifold right not make it another loop ?

Scott

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Bart

re: supplemental

Good idea on supplemental panels, works great
(keeping in mind supply water temp), but where supplemental is not required and where solar gain is the concern, dedicated perimeter loops helps, and can be throlled independently. With outdoor reset you should not have to
reduce flow to all loops, slab and air sensors are required.
I hear Roth's multi temp manifold with mixing per loop, they can actually reject heat in this case.
Just a though - Cheers

Bart

re: supplemental

Good idea on supplemental panels, works great
(keeping in mind supply water temp), but where supplemental is not required and where solar gain is the concern, dedicated perimeter loops helps, and can be throlled independently. With outdoor reset you should not have to
reduce flow to all loops, slab and air sensors are required.
I hear Roth's multi temp manifold with mixing per loop, they can actually reject heat in this case.
Just a though - Cheers

Mark J Strawcutter

Danfoss

makes a couple of TRV variants designed for just such use. They specify limitations on square footage and/or tubing length - perhaps for the very reason you're concerned about?

Mark

Boilerpro_3

No, was just looking for a way....

to zone room by room with radiant floor without wires or power required. I am adding several radiant floor rooms to an existing standing radiation system. The rads are all getting TRV's with constant circ and outdoor reset, so I thought it would be nice to do the same with the radiant floor rooms. Maybe I'll just be using telestats or zone valves here instead of TRV's .
I like the idea or continuous perimeter radiant, with supplemental radiant on TRV's. Will keep that in mind for future reference.


Thanks,

Boilerpro

Mike T., Swampeast MO

Check out

Danfoss "Radiant Specialties" FHV series controls. Similar to TRVs but not identical. "A" series modulates on air temp; "R" series on floor temp.

Haven't used them nor do I have exact specs regarding flow but do believe they are ½" only. There is bound to be an upper limit regarding tube length, but you should be free to make runs as short as necessary without concern for flow balancing problems.

As long as you stay within design parameters there shouldn't be a problem with "running out of heat" as the valves close:

1) The system will probably be reset and you'll need a fair amount of flow at all times anyway.

2) By throttling flow the valve will effectively lower temperature through the entire loop--since it will only be closing because the desired setting is close-at-hand the floor will be warmer. Combine that with the lower temperature of the water and you'll get less heat transfer through the entire loop and everything [should] balance.

The "R" version that modulates on floor temperature should be very useful in places with high heat loss that require supplemental heat. It will allow the floor to heat the space much of the time with the proportionally controlled supplemental heat kicking in as necessary.

The "R" version should also be quite useful in areas with unusually high solar gain in the floor.

Remember that the "A" version modulates on air temperature and will be fully capable of making the floor hotter than typically assumed for best comfort.

I'd try to size everything so that an "A" valve set at a "normal" setting is using 75-80% of the available BTUs AT MAINTENANCE LEVEL. This should give decent headroom for raising temperature without extreme overshoot as the floor increases in temp. Calculate at a couple other outside temps using same amount of "headroom" to get your "ideal" reset curve.

Mark J Strawcutter

That's what I was referring to

one source of info is:

http://www.danfoss.com.cn/product/FHVvd31a102.pdf

which contains the following wording:

Note: If using the FHV-A for room temperature control,
the flow temperature should not be permitted to
exceed the maximum recommended by the floor
heating supplier. When the FHV-R is used for controlling
floor heating, the heated floor area should
not be greater than 10 square meters

Mark.

bill clinton_3

Danfos TRV radiant

About six years ago, we did a residential care facility of about 35 rooms using only Danfos TRVs. Used condensing water heaters as the heat source, plugged circulator into wall for constant circulation (This was in San Francisco where heat is needed all year round)

Worked great. Perfect temperature modulation. 35 zones, no wires, no relays. It was a very good way to go.

Bill

Paul Rohrs_2

Oventrop

I was intrigued by a system Mark Eatherton spoke of some time back as his "dream system" (?) He used Oventrops Uni-box as individual zone controls and it sounded like it was the cats meow. I would definately get Mark E to expound on it for you. Hopefully this will be a topic at the Wetstock III.

PR

Bill_17

Bill_17

TRVs on floor heating

Bill_17

TRVs on floor heating

Bill_17

TRVs on floor heating

Here's another way to use TRVs on floor heating systems where they act as thermostatic injection valves.

Bill_17

TRVs on floor heating

Here is another way to use TRVs to control floor heating systems. The TRV acts as an injection valve for the heating circuit