Triangle Tube Prestige System, w/ Smart Indirect - higher temp zone with Rescom 2100 aluminum basebo

jb_14

Having a TT Solo 110 and Smart Indirect system put in in my older house with new addition.  Am an engineer and contractor - getting mechanical pro install help - but designing it myself.



Primary Secondary, zoning with grundfos circulators, honewell/sparco mixing valves for low temp zones, and 6 zone Taco Switching relay.



Need to have a 'high temp' zone upstairs with higher heat losses due to old house wall characteristics, and existing plaster ceilings and floor bays not accessible for plates and barrier pex for low temp.  Main option is hot water baseboard - planning to run it at 140-150 to satisfy heat loss but to try and keep the returns in the condensing range as much as possible.  So I've decided to go with the Rescom 2100 product.



<a href="http://www.ecotechhydronics.com/RESCOM%20Brochure.pdf">http://www.ecotechhydronics.com/RESCOM%20Brochure.pdf</a>



I really like the architectural profile - as the wife doesn't want radiators as wall space is at a premium with too many big old house windows (a good thing except for the heat losses).  I am planning to pop the old mop boards and put this stuff back in 'as the mop board' base moulding - and add cap and shoe for effective radiator disappearance.



So - could I increase the linear feet of Rescom 2100 give me enough radiation to allow lower water temps?  Has anyone had any success with these aluminum baseboards at lower temps - or at any temps.



Are there any potential aluminum corrosion/cathodic issues from the copper and aluminum?  I've got copper going to it - dielectric unions?



As if that's not enough...here are my boiler related questions associated with this high temp zone...With the TT Solo 110 - I know I've got on board priority for the domestic indirect, then I've got the central heat supply temp set through the outdoor reset and curve parameters through the Solo 110 mcba.  Is there any way to have the TT 110 utilize 2 central heating set temps?  1 - at 150-160  for the upstairs baseboard and 1 - at say 120 (when high temp isn't calling)  for the low temp under floor radiant with extruded plates - in the well insulated addition - so I can maximize condensing and efficiency?  How could I do this?



Would there be some way to split the outdoor temp sensor signal with a switch to 'fool' the TT 110 into going further down the temp curve when the high temp zone isn't calling for heat.  thus the mixing valves will just open up all the way when the water temp is below the set point.  And when the high temp zone does call for heat - switch over to the actual outdoor temp to get the 110 to fire for the higher temp water needed for that zone.



A related question is without this 'trick' what is happening to my efficiency when the high temp and low temp zones are calling - and the boiler is firing to satisfy the higher temp - the low temp zones are mixing down - is the net effect of the mixed return water back to the boiler low enough to get me condensing efficiency (3 zones of flow at 100 degrees mixed with one zone of flow at 130 to 140 degrees).  Am I just losing a few points or is it worth 'tricking' the 110 into modulated fire when the higher temp zone is not calling.



Does this make any sense?  Any ideas or experiences?  Would a diagram help?



Sorry so long - and thanks for any thoughts.  Love learning from you guys.

Unknown

Ever thought of,,,,,

TRV`s on each rad?

Mark Eatherton

It works, however....

Like any series connected emitter, as the fluid goes through the devices, it gets cooler, which requires more linear footage to operate at the lower entering temperatures. Also, you will most probably have to use the Long Island installation method (wall to wall emitter) in order to get where you need to be, even at elevated operating temperatures. There is really just not that many square foot of EDR per linear foot of the board.



One could hook all emitters in parallel to a centrally located manifold and increase the output, but at a heavy burden to the wallet...



As for corrosion issues, no. THe bond between the aluminum and the copper is a dry fit, and you would need an aqueous solution in order to complete the galvanic battery. As long as you are dealing with a true, tight, closed loop system, dielectric unions are not necessary.



I am not as familiar as others here on teh MCBA control, and will defer to them, but I don't believe you can do that, because if you get a simultaneous call, you will need the boiler to go to the higher set point, and the only way to protect the lower temp zones is with a mixing device.



That said, I have heard rumors that a certain mod con boiler will be coming out with a dual temp system, but it would still require some means of protection for th elow temp zones.



As a possible alternative, if you use non electric TRV's to control the zones, and they are within 20 degrees F of each other at design condition, the lower temp zone will only bleed just a little flow to satisfy its demand. More people need to start paying attention to these proven control strategies. They deliver EXCELLENT comfort, and cause the system as a whole to modulate, which is good for energy conservation.



ME

Mark Eatherton

Great minds think alike...

some just use LESS words than others :-)

jb_14

Thanks guys.

Thanks.   So I've got non electric thermostatic mixing valves going on the low temp zones before the circs already bought and piped.  (as I was planning to run the Solo 110 at the higher temp zone temperature - and then mix it down for other zones) thus my low water temp zones would be protected - the sparcos will mix it down if it's hot - let it flow if t's low?  yes?



So I would be protected - if I could execute my dual low temp scheme (150-160 when high temp zone called) and only fire to 110-120 when other low temp zones called (by spoofing a higher outdoor temp) and high temp wasn't calling.  As a bedroom zone it will have less run time and specific times - later in evening and early morning only.



I am planning to do the rescom zone in two parallel runs - supplied by  3/4 copper from the grundfos - splitting to two branches of 20-30 ft. of rescom (1/2" flow through).   i hadn't really thought of it as a manifold - but yes - i could do some flow balancing there if the parallel branches had different needs - globe valve, right?  (and as Dave recommended could I even go with TRV's at each branch to further balance?) though could this result in problems if the TStat called for heat and the TRV said no more (or I guess you're saying TRV's instead of TStat and Circ?) 



I think with this zone's older house heat loss characteristics (slowly improving - with more insulation and eventually refitted or new windows) - I think I'd prefer to have it on a set-back capable programmable Tstat - rather than on set it and forget it TRV's.



Again thanks for your input.  Really appreciate it.

CMadatMe

To bad you already chose a TT

Because a Viessmann Vitodens 200 will do exactly what you want the Solo to do. Can run actually run up to 3 curves if you wanted plus still have domestic priority. You could also get indoor feedback for both the high temp and low temp curves with the Vitotrol Remote Control. No need for tricks just plenty of treats. Boiler is 96% out of the box and 98% at full mod. Doesn't vent PVC though. You can vent this with 2" CPVC rated for venting which Viessmann has for a boiler of this size. Can also take combustion air from inside the room if need be. Alot more benefits, take a look

jb_14

Vitodens vs. Prestige Solo

Thanks wizard.  I definitely looked at the Vitodens - but I am thrilled with my Solo 110 choice.  I just couldn't make the budget work for the Vito (daydreamed about it a little), but made the decision to go for the value play - much less expensive for me and perhaps second place to the Vitodens - but a worthy competitor in my application  from all of my research.  Throw in the training program at Triangle Tube outside of Philly, the excellent engineering and tech Support from there, and the support and stocking of my suppliers, and it was a done deal for me.



I just hope I don't spend the savings trying to set up that 'tricky' dual curve!   

Mark Eatherton

Caution!

Radiant heating is NOT conducive to set back and recovery.



The convective capacity of those little surfaced radiators is minimal at best.



Remember, you are heating MASS, not the surrounding air. If you let it cool down too much, it may not recover in time to keep you comfy.



Also, your conservation effort is now coming from the source, and the thermostat (programmable set back) does not speak the same language as the MCBA on the boiler, so the stat will get so confused it won't even try and set back at night. Better off maintaining a cooler sleeping environment in general instead of expecting the system to sit up and pay attention on your command...





Been there, done that, threw the program out, didn't increase fuel consumption, increased human comfort conditions.



ME

CMadatMe

JB

Hopefully it works for you. Solo is a good boiler and I glad to here your happy with your choice. I hear you on the possible cost of trying to be tricky because the new Vitodens 200 is not much more than that Solo so you could eat that cost up real quick.

jb_14

good points on the set back with radiant

I was definitely thinking of a radiant Tstat with a floor sensor (or nearby wall sensor with the baseboard rads).  so at least I can read something along with air temp to 'speak to the rads'.



my thinking was with the old house heat loss characteristics of this zone - the constant losses would make it advantageous to let it fall back during the day - and somewhat 12am-5am - with gentle warming for 6am-8am and 7pm-10pm - when there are people in these rooms and not under down comforters.  cool sleeping indeed - I'm a big proponent of that - let the blankets and body heat do the work.  just as long as I can figure out the 'heat up curve' and have my wife happy when she rolls out of bed.



your points are well taken - in that the response and lag of the baseboard rads - vs - air temp - would need the right Tstat and would need to be determined/tweaked with some real world conditions (love experimenting and taking measurements to find the sweet spot).



Also - wouldn't these aluminum rads - be much lower mass and volume than traditional CI - and actually heat up rather quickly?  I realize I need time for them to heat the objects in the room as well.



Appreciate the input.

NRT_Rob

you can do two temp with any boiler

Tekmar 422 control with a mixing valve.



if only low temp zones are calling, system runs in low temp.



If high temp zones are calling, system runs to high temp.



plus you get zone sync, indoor feedback, advanced boiler firing controls... good stuff.

Piper

two temp TT

i worked out a way to work a low temp and high temp on the TT with my local sales rep who is pretty savvy, and he passed it by the TT engineers who gave it a seal of approval. it works great in our n. california climate, but not sure where the intended installation is.

it doesn't give two curves; the low temp is on the curve, the high temp zone achieved by putting the outdoor temperature sensor on a low voltage relay. when there is no input from the outdoor sensor, the TT assumes a temperature of -22*F and so it runs as if it were -22 outside, giving you higher supply temperatures when the outdoor sensor is interrupted.

so basically the way it works is if only the low temp zones are calling, the boiler runs on the curve. when the higher temp zones call, a relay opens the outdoor sensor circuit and the boiler goes into assuming it is -22 outside and delivers hotter water. your mixing valves mix down the higher temp water to the low temp zones at this point; otherwise they just remain wide open.

i'd make sure the tekmar interfaces well with the TT. i've seen another application of a tekmar control and a modcon together but the tekmar wasn't able to actually control the curve or the supply temp of the nodcon directly, but by another less than ideal method that i don't recall. 

Piper

also

yes you could increase the linear footage of the baseboard to give you the same btus at a lower water temp