Is it bad to turn some rads off each night?

bipbap

We live in a small 4-apartment building with a single pipe steam system and despite years of tinkering/swapping radiator vents and adding basement vents, some radiators are maybe just too big for certain rooms and make them too hot. (It is a 100 year old building, and for sure radiators have been moved around and room sizes have changed due to renovations)

So at night we usually fully close the valves on our kids bedroom radiators so they don’t become a sauna. The rooms then easily stay comfortable until morning.
I realize we could swap the radiators for smaller but that seems trickier than just shutting the valve at night.

Is there any reason this is bad for the overall system? Like shutting 2 of 14 radiators in the building?

Or bad for the valve to be shutting it every day?

Thanks in advance for the advice!

KC_Jones

The valves usually don't fully seal unless they are brand new. With them not fully sealed, steam gets in, water can't get out. Over time the rad will start to fill with water.

Now, doing it only at night probably isn't such a big deal, but remember, shutting that radiator and it's vent down could impact the other units and the balance you have worked on. Normally we recommend just turning the vent upside down which is more effective at turning it off. You could add a valve between the vent and the radiator to turn it off at night, as turning it every night would probably wear out the threads.

All that said, I'd suggest a vent TRV in the situation you present, an overall well balanced system that has some minor overheating issues. I run one in my master bedroom for the exact reasons you state.

SteamingatMohawk

Do the bedrooms get too hot during the day? Are you using adjustable vents?

bipbap

FYI: These valves actually are brand new, installed in last 2 years or so.

KC_Jones

bipbap said:

FYI: These valves actually are brand new, installed in last 2 years or so.

They won't stay that way if you keep turning them on and off. Packings will wear, seats will wear. The valves are really intended for maintenance only, removing a radiator, painting etc.

bipbap

What brand/model TRV would you recommend for this situation?

dabrakeman

You could try just Ventrite #1 radiator vents on those bedroom radiators. It is an adjustable vent and can adjust right down to closed.

AdmiralYoda

I vote TRV. Check out supplyhouse.com.

https://www.supplyhouse.com/Honeywell-Home-V2042HSL10-1-8-One-Pipe-Steam-Thermostatic-Radiator-Valve

Might take a little trial and error but you can effectively turn a big radiator into a small one with one of these.

ChrisJ

TRV's will fix the issue.
I prefer Macon and my second choice is Danfoss.

SteamingatMohawk

For those who don't have Dan's "Lost Art", i believe it is important to know one point he makes about TRVs (page 160).

The short version is, if the TRV doesn't also have a vacuum breaker, when the TRV shuts as the radiator cools down, it creates a vacuum, which can draw steam into the radiator, resulting in an overheated radiator. Presumably it depends on how fast the radiator cools down compared to the TRV.

This seems to be a fairly important feature.

I looked at the one mentioned above and there is no mention of a vacuum breaker.

This Macon does.
https://supplyhouse.com/Macon-Controls-MAC-OPSK-W-EVO-1-8-Threaded-One-Pipe-Steam-Straight-Valve-Assembly-with-EVO-28-Operator

Here's the Danfoss (....G0140),

https://danfoss.com/en-us/products/dhs/radiator-and-room-thermostats/radiator-thermostats/radiator-valves/ra2000-valves/#tab-products

Has anyone experienced the problem Dan mentions in his book?

ChrisJ

SteamingatMohawk said:

For those who don't have Dan's "Lost Art", i believe it is important to know one point he makes about TRVs (page 160). The short version is, if the TRV doesn't also have a vacuum breaker, when the TRV shuts as the radiator cools down, it creates a vacuum, which can draw steam into the radiator, resulting in an overheated radiator. Presumably it depends on how fast the radiator cools down compared to the TRV. This seems to be a fairly important feature. I looked at the one mentioned above and there is no mention of a vacuum breaker. This Macon does. https://supplyhouse.com/Macon-Controls-MAC-OPSK-W-EVO-1-8-Threaded-One-Pipe-Steam-Straight-Valve-Assembly-with-EVO-28-Operator Here's the Danfoss (....G0140), https://danfoss.com/en-us/products/dhs/radiator-and-room-thermostats/radiator-thermostats/radiator-valves/ra2000-valves/#tab-products Has anyone experienced the problem Dan mentions in his book?

I have not tried it and I'm always too busy to experiment these days but I'm fairly confident if the 5 TRVs on my system didn't have vacuum breakers it wouldn't matter.

But I guess I could see if you had a large building with many radiators and they all had TRVs you'd need a way to break the vacuum at the end of each cycle.

In my case my Gorton main vents would allow enough air back in I think.

During a cycle when the TRV closes, vacuum breaker or not that radiator keeps pulling fresh steam in until the cycle ends.  There's no way it would pull air in through a restrictive vacuum breaker when there's steam at a positive pressure available at the radiator inlet.

SteamingatMohawk

That's why I asked. I was skeptical that there could be much of a difference, but thought that if Dan put it in his book there is something to it.

JakeCK

How about covering them with a blanket? 

ChrisJ

tommay said:

No, not a problem at all. No worse than turning off a faucet. But, it's good to leave them a little open. Use them like the valve they are, to control flow.

You most certainly do not leave the valves a little open on a single pipe steam system.

Either fully open or fully closed.

DanHolohan

I worked for years for the Danfoss rep in NYC. When they first introduced their TRV for one-pipe-steam it created big problems for the jobs we sold. The TRV would shut the air vent. The steam would condense and form a vacuum inside the radiator because no air could reenter the radiator through the air vent. That vacuum drew more steam into the radiator, causing the rooms to overheat, which is exactly what the TRV was supposed to prevent.

We visited many jobs before we realized what was going on. We suggest to Danfoss that they add the vacuum breaker to the TRV's valve body, placing it between the closed air vent and the radiator. That solved the problem.

Keep in mind that Danfoss' home is Denmark, where there is no steam heat. The same applies to most of the other European countries where TRVs come from. It was a mistake that got fixed in the '80s.

Stick with Danfoss or Macon (from Tunstall https://tunstall-inc.com/macon-controls/one-pipe-steam/) and you can't go wrong.

SteamingatMohawk

That's good enough for me.Thanks, Dan.

DanHolohan

My pleasure!

ChrisJ

tommay said:

Chris, so how would your logic apply to adjustable air vents, which are basically valves? Or are you just worried that water wouldn't drain back through a valve that is only slightly "open" ?

This is common knowledge with single pipe steam systems. I do not feel it's my logic.
Steam can get in, water can't get out and the two mingle and decide to throw a loud party.

SteamingatMohawk

You didn't answer these questions. Please do.

Do the bedrooms get too hot during the day? Are you using adjustable vents?