TRV's to address cold side of building on windy days

gfrbrookline

I am looking to add TRV's to a one pipe steam system to prevent overheating of one side of the building on windy days. When the weather is good the building is balanced, took a lot of work but we got there. Can't say enough good things about steamhead's advice and the use of Big Mouth main vents. One side of our building faces East and is exposed to the weather and wind in storms. We cant force the owners to replace the windows so the drafts cool them down considerably. The west side is sandwiched with another building and all of the units have new energy efficient windows. We have a Honeywell VisionPro TStat set to 68 with 3 remote sensors, 1 on the west side 2 on the east. On stormy windy days the east side of the building will be 64 and the west side will be 75 and the boiler kicks on hourly. I am hoping TRV's on the West side in the unit with the sensor will keep it more even during windy days and force more steam to the east side.

Thoughts, recommendation on which TRV to use, Honeywell, Danfoss or Macon?

nicholas bonham-carter

Try adjusting the size of the radiator vents first, with very slow Hoffman 40's.
The radiators in this building were no doubt sized adequately to handle anything Mother Nature could throw at them. Will the cold side receive steam simultaneously with the hot side?
You may still need more bigmouth vents.--NBC

gfrbrookline

Thanks, On non windy days the building heats evenly, within 1 degree, and probably did so on windy days before most of us improved our windows to eliminate the drafts. I am classifying windy days as 30+mph winds.

Steamhead calculated my mains at 1.5 cubic feet so 1 big mouth should be more than enough.

I was thinking that adding TVRs to the unit that overheats on windy days would allow the system to work normally on calm days and prevent overheating on stormy days.

Paul48

Remove the sensors from the apartments with the old windows, and tell those folks they might want to upgrade their windows. Why punish the folks that have done it?

MilanD

How big is the building, how many mains and are mains separated by side, or by floor, or mixed up? Trvs may not solve issue completely. Sounds like you want to increase venting to radiators in units with old windows to get heat to them first, and lower the venting to the other side. Trvs would then go on the newly regulated cold side rads. Counterintuitive, I know.

Depending on the setup with mains and risers, increase venting to old window side and slow down to new window side may mean adding extra vents on the valve side of the rads in cold units first, and this alone may do the trick. If not, trvs on those same rads will then push steam to the other side when they are full.

May take calculating all pipes sizes, lenghts, volumes, and from which main they are coming from, and then figuring out how to get steam into rad risers on the old window side of the building first, but not excesivelly to where it woulf be delayed on the new window side ...

Fred

If the entire building is balanced 90+% of the time (except when the wind is 30+MPH) I would try adding another Bigmouth on the main that feeds that side of the building before I invested in a lot of TRV's. Steam will take the path of least resistance and if you can push air out of the main (hopefully that side of the building is on a separate main) easier, that may do the trick. If there is just one main that feeds the entire building, then TRV's may be an option. Even though one Bigmouth may be enough, based on volume, easier/faster movement on one side of the building may play a role here.
How many units on each side? single story or multi-story? Is that side of the building further away from the boiler?

gfrbrookline

Unfortunately the mains run on the north and south sides of the building so that is why I think the TRV's might be my best option.

The boiler is on the west, warm and insulated, side of the building. 3 story brick condo building built in 1915.

MilanD

Can you quickly draw where the boiler is, where the mains are and and which is the cold side on the windy day? Take a pic if the schematic and post. Is the cold side closest to the boiler or farthest?

MilanD

I'm asking bc this will determine how to nudge the steam to where it needs to go first.

Paul48

Let me see if I have this right.........Some of the folks upgraded their windows ($), now there's a situation caused by those that didn't, and the ones that did are expected to spend more ($). On top of that, because some didn't, everybody spends more ($) for fuel.

gfrbrookline

sad to say but yes. We created an out of balance system because many of the owners did the right thing trying to make their units more energy efficiency and we had some hold outs that were not willing to do the same.

Paul48

Use association money and get the rest done. Credit the owners that paid out of their pocket, over the next year.

Paul_11

TRV's are great and will do what you want if you are running at low pressure.

However, they work best when the operating pressure is as low as possible. At one psi they almost work perfectly and completely keep all sections of a radiator cool. However, as the operating pressure increases more of the radiator will get hot even though the TRV is off.

What pressure does your steam system operate at.

If you have not master vented the building, that should come first.

gfrbrookline

System runs at 14oz cut out 2oz cut in. I installed a Danfoss with a vent rite 31 in my living/dining/kitchen room and am amazed at how much more control I have over the vent rite 1. Winds were about 20-25 mph yesterday and my unit did not overheat but was able to maintain 68 on the windward side.

gfrbrookline

I put a danfoss trv with a ventrite 31 vent on the living room radiator last week, today water came out of the vent right before it closed. I have never had water issues with this radiator, it is pitched correctly. Is this common with trv's?

Fred

Not typical. How many TRV's have been installed? With each radiator that is closed off, the boiler becomes more and more over-sized, building pressure. If the boiler is shutting down on pressure, what is the Pressuretrol set at? Too much pressure can prevent condensate from getting out of the radiator. One of the cons of using TRV's and/or shutting off radiators.

jumper

Fred said:

Too much pressure can prevent condensate from getting out of the radiator.

Why?

MilanD

jumper said:

Fred said:

Too much pressure can prevent condensate from getting out of the radiator.

Why?

Closed off trv keeps vacuum, like a straw in a glass which you close off with your finger and lift out. Then, as steam goes in, slowed down condensate is pushed back and kept in the radiator. Thus, trv can work well sometimes, and not so well other times.

gfrbrookline

Just one trv, Pressure is 14oz cut

jumper

>>Closed off trv keeps vacuum, like a straw in a glass which you close off with your finger and lift out. Then, as steam goes in, slowed down condensate is pushed back and kept in the radiator. Thus, trv can work well sometimes, and not so well other times.<< </p>

Yes it happens but where in a one pipe can enough condensate collect to block steam?

MilanD

I> @jumper said:
> >>Closed off trv keeps vacuum, like a straw in a glass which you close off with your finger and lift out. Then, as steam goes in, slowed down condensate is pushed back and kept in the radiator. Thus, trv can work well sometimes, and not so well other times.<< </blockquote>
>
> Yes it happens but where in a one pipe can enough condensate collect to block steam?

It's possible. Water column pressure built in the rad plus vacuum would be equal to oz pressure of steam. Over time, rad is blocked off. I'd expect it also to possibly, start shooting water out of the air vent, unless it's a float type that would block off on water rise in the radiator.

gfrbrookline

I replaced the ventrite 31 with a hoffman 41 and discovered the radiator was correctly pitched side to side but was slightly off pitch front to back so I removed a quarter from under one leg and problem solved. I am usually a huge fan of ventrite vents but I have to say the hoffman is much quieter, no click.

EBEBRATT-Ed

I like the Danfoss the best but that's just my preference. I am sure the other brands are fine.

Since the building is balanced TRVs are the only way to fix this until the windows are replaced. doing anything with the vents will wreck the balancing.