TRVs

Rodney Summers

Mark I agree in part with your opinion, a properly sized emitter system designed to accommodate the full gpm of the boiler loop (munchkin 8gpm) without primary/secondary

let the burner fire to the load, trim the reset curve to match the needs of the space save all that $$$ spent on TRV's KISS

Jimbo_5

TRVs

I am curious about using TRVs with my home HW boiler. I will be using an Ultra-80 with 7 good-size ci rads and 20 feet of ci baseboard. There are 2 rooms that I cannot install a TRV in or on, such as the bathroom where the piping is within the concrete flooring, and one radiator where the in-floor piping leaves no room to wiggle one in and the supply/return pipes are not accessible in the basement. Will it make much of a difference if a room or 2 are not controlled by TRVs? The system is a converted gravity and I will using a constant circulator and outdoor reset. Also, which is the better TRV to use on this system? And will the TRVs work well with the ODR? Any ideas or suggestions will be greatly appreciated.

Mark Wolff_2

TRV's

TRV's are useful if you have rooms that were not equally heated. If one room is much higher temp than the others, and your system allows for TRV controls, you can use it to cut out the baseboard/radiator early while the rest of the house continues its cycle.

In general though, especially with outdoor reset, you shouldn't be needing to use them. The goal of the TRV is to balance rooms better, but with outdoor reset bringing a lower temperature of water to your radiators and baseboard, you won't notice any improvements to the system efficiency or the home comfort level.

Jimbo_5

Thanks Mark

Ok, now I'm confused. I thought TRVs would work well with the ODR. But someone did mention that at lower temps, determined by the ODR, the TRVs migh not open or close properly. Nontheless I thought it would be better to use the TRVs rather than just run the system in constant circulation without them. What do ya think?

Jeff Elston

TRV

I have Tvr's in my home w/ ODR. I have wall to wall base board, last 2 years i used zone valves and the noise of expanding pipes was no good. This year I put in TRV and and room temps went flat line and its great I am more comfortable than ever before. Yes I constant circ and out door reset and TRV and loving it good luck

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Ted_9

Mark

I respectfully disagree with Marks opinion here. I believe outdoor reset and the TRV's will give you more comfort. That's what my family and customers tell me.

I use a Buderus R2107 with a Buderus boiler for this type of system. Their outdoor reset and trv's a a great match. Also a Viessmann outdoor reset control is an exceptional choice.
Massachusetts

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Brad White_153

I second Ted's motion and Jeff's too.

TRV's work exceptionally well with ODR. They are "high limit" devices of course but they even out what may be over-sized radiators and cut back on rooms with high solar gain.

In my house and my Susan's, the bathrooms do not have them for logistical reasons and I see no reason why I would want them anyway- hard to overheat a bathroom IMHO and you get a bypass by default. (There is a restrictive balancing valve on each, mind you- we are not foolish!)

Reset does help prevent overheating in general, house-wide and the bathrooms are not overheating ridiculously. I do see Mark's point in that ODR might not require TRV's in an ideal world.

However, TRV's even out the playing field and cancel out a lot of solar and internal heat gain variables as well as allowing some rooms to be cooler as you may want them, such as bedrooms and spare rooms.

Put TRV's where you can and don't worry about perfection. It does not exist. You will save money and increase comfort almost effortlessly.

Jimbo_5

Thanks Guys

I will use the TRVs and the ODR. How about eliminating the gas-fired HW heater and adding an indirect tank? Can I expect a noticable reduction in gas usage? I expect I should. Which indirect tank might be best when coupled with the Ultra-80? Naturally, they suggest their own, but is that MY best choice for efficiency and reliability?

Uni R_2

fast and loose math

energy for hot water now... maybe 600?

ultra might cut that by 200 down to 400

200 a year savings over 10 year = 2,000


non-math

in the meantime, better for the Ultra over the summer

better hot water recovery

better for the planet


value the non-math stuff if you can't justify it with the math

btw, weil has a great tank... made by acv, a belgian company

bb_7

Danfoss

Jimbo:

I was with Danfoss for many years before I wondered off to the distribution side. They make the best TRV on the market bar none! IMHO.

They are built to last and very reliable, you won't have a problem. They work great w/ ODR. You are making a good choice.

For more info you can check their website @: http://danfossheating.com , or call Tech Support @ 443-648-1205.

Warm Regards,

bb

Jimbo_5

What about?

I can't help but wonder if the large mains (2" black pipe) that run throughout my unheated basement will affect the operation of a system that runs with a constant circulating pump relying on the Ultra's supply and return water sensor. Might this cause the boiler to think the heated rooms are needing heat?

Brad White_159

It is a load

yes.

Every 100 feet of 2-inch bare pipe at 120 degrees in a 60 degree space will lose about 4,500 BTUH, enough to heat a room. This rises, in very rough terms, by about 1,000 BTUH for every ten degrees above 120 F.

Jimbo_5

Ok, but where does that lead?

Thanks, Brad . . . But where does that leave me? Should I have figured the uncovered pipes in the basement into the Heat Loss Calc? I've got about 40 feet of 2" that then reduces to 1" for a few more feet before coming up into the 1 st floor radiators, or into the walls to run to the 2nd floor. I have finally reasoned (thick headed as I am) that the Ultra was a better install than the cast iron, fixed -fire-rate boiler. And I liked the constant circulation to let the Ultra's sensor determine the rooms' heat, in conjunction with TRVs. Now, I seem to be WAY back to square one. Where do I go from here?

Brad White_160

No hard harm Jimbo

You can always insulate the lines and if you want heat in the basement make it a positive (read: controllable) statement.

You are ahead of the curve with the Ultra versus Cast Iron. Key reason is that the modulating temperature will limit the losses on the average day. Still a loss but not at a high constant. Can you insulate the pipes?

Yes, I would have figured the losses into the equation not so much as a heat loss to the building (you of course took the basement ceiling/first floor structure as a heat loss, right?)

The factoring would not have affected my boiler sizing (unless it was close to an up-size in which case I would insulate the heck out of them).

Rather, for you, just take the loss as an operating expense, some of which you recoup as heat to the basment. It is just uncontrolled heat, that's all.

Jimbo_5

Very nicely put

As I see it, years later, it seems that the lengthy pipes in the basement actually served to heat the first-floor flooring somewhat, as well as warm the basement itself. My cousin lives next door, in the same 1930's house, and they put a room in the basement, insulating the basement ceiling. Well, there kitchen really showed a noticable change in temp. To be perfectly frank, I had been thinking of throwing an old radiator or two (or a leftover fintube element) in the basement on the return piping of my existing boiler (a 1956 Weil McLain). But that was prior to deciding on a needed upgrade. So, I would rather not insulate the pipes, unless necessary. I was concerned that the cooling 2" feeds would cause the Ultra to cycle much sooner than needed, sort of like trying to "heat" the basement. Perhaps the constant flowing loop won't be as affected as I thought. For me, instalation & piping is the easy part, figuring the sizing, trim and controls is the hard part. And asking for help is, well, difficult at best.

Brad White_160

Thanks, Jimbo

If it is any consolation, not all of my piping is insulated either. Work in progress but most is.

The key to the "it heats the space" concept is, how leaky is the basement? If the loss rate exceeds the purported benefit to either the space above ("wishing for warm floors") or the basement itself, you are still running a deficit. The positive side is that basements are immersed in a 50-degree heat sink, the earth they sit in.

Basements tend to be the incoming point for infiltration because they are low in the "chimney effect train" and often harbor water heaters, boilers or old openings therefor. Even if the new equipment is direct-vented, sometimes these openings remain. Even cleanout doors in unused chimneys.

An atmospheric water heater can draw at least 50 cfm of space air through a 3-inch flue; a 5-inch atmospheric boiler flue can draw over 200 cfm. Compare this to the presumed infiltration for an entire house. On a per SF basis, basements are rather drafty places.