TRV valve vs shutting radiator entry valve for rarely used 1-pipe attic radiator

NYCDave

My wife wants me to install a TRV on our one-pipe steam attic radiator since we are never up there, so we can set it to the minimum temperature setting to save heating oil. The boiler maintenance guy suggested this. I said why not just shut the radiator entry valve, the attic will stay warm enough from heating the rest of the house. She said the maintenance guy said not to do this, it would cause damage.

I have read a fair amount on this (excellent!) forum when we moved in to understand the basics of one-pipe steam heating. As I see it, if we set the TRV to minimum, it would basically close the vent at the beginning of each burner cycle, preventing any steam from entering the radiator, unless the room temperature dropped below about 45 degrees (very unlikely). How would this be any different from just shutting the main entry valve on the radiator? Am I missing something?

Thanks for any insights... I did search the wall for this kind of question, but could not find anything that quite answered this.

Abracadabra

Unless there's something missing from this story, I can't see a problem with shutting off the valve to the radiator.

KC_Jones

The better bet is to just turn the vent upside down, in most cases that effectively closes the vent and steam won't go where there is air. I am not a vent expert so maybe a pro knows if there are vents that don't do this? So the air can't get out the steam won't come in. The problem with closing the valve is this. Unless you personally rebuilt that valve you really don't know how well it will shut off. If even a little bit of steam gets through it will condense and water won't be able to get back so you basically start filling the radiator with water, it can and will happen (I learned the hard way). The TRV you speak of would go on the vent anyway so just turn the vent upside down it's simple and it works again I learned from experience. You might get a miniscule amount of steam in there on a long burn, but it probably wouldn't go beyond the first section and it won't stop the condensate from returning to the boiler. I have torn some of my valves apart to check them out and the rubber gasket is generally toast and without that you don't get a seal to stop steam.

nicholas bonham-carter

you can also turn the air vent upside down, and that will keep the steam from rising. that mimics the action of the TRV.--NBC

KC_Jones

nicholas bonham-carter said:

you can also turn the air vent upside down, and that will keep the steam from rising. that mimics the action of the TRV.--NBC

We must have been typing at the same time...lol

STEAM DOCTOR

Leave the rad on. A warmer attic means a warmer second floor and less oil burnt. Just my gut feeling. Use a small air vent.
There are some unknown variables. Shutting the rad in essence makes the boiler bigger. If boiler is properly sized or too large, then in essence you will create an oversized boiler by shutting the rad. That's bad. If boiler is too small then shutting rad will bring heating system more in line with boiler. Just a few thoughts to ponder.
There are probably many more ways to save money (venting, cleaning boiler water etc etc).

NYCDave

Thanks so much everyone for your comments!!! This website is such an amazing resource!!!

It did occur to me, from reading many posts on here, that removing a radiator from the system, by any method, would alter the balancing and could effectively create an oversized boiler, but my wife isn't too interested in hearing this. She said it (TRV valves) worked for a friend of hers, so we should try it. I think I will try the inverted valves!!! Cheap and easy!!! Also good to know the reason why just closing the entry valve may not work, and certainly true that I know nothing about the valve, and it may be the original from when the house was built in 1929 for all I know...

Had not thought about the idea that if the attic is cold, the second floor will require more heat... interesting point, I wonder how to determine which would win out (nominal saving in not heating attic, vs. required extra heating of 2nd floor....)...

Also definitely true that the whole system needs a revamp, but it's such a big and intimidating job, I haven't been brave enough to take it on... add in that what I'd really like is to convert by burner to a gas burner (but keep the boiler, which is a fine boiler), and that really seems to make it complicated...

KC_Jones

As a homeowner I would encourage you to read as much as you can on this website, I have learned so much over the past year! I actually have 2 TRV in my own house, but now realize I may not have needed to spend the money...they are a bit pricey. Yes turning the vent upside down is free and you can find out how your system reacts to this change. If it works for you great if it doesn't at least you didn't spend any money! The reason I say I may not have needed the TRV is because I didn't realize until later that my system is imbalanced with the venting. All my rads have the same vent (I have some new Gortons waiting to go on now) which doesn't balance the system and explains most of my uneven heating. The idea you are exploring would work better if the boiler had a hi/lo fire on it since the boiler could effectively downfire to the reduced radiation, but without that it probably won't really save you much turning that rad off like Steam Doctor said. Unfortunately hi/lo doesn't come on any (that I am aware of) residential steam boilers. Good luck with it and welcome to the site!

Jamie Hall

There is a serious problem with using the valve as a control on a one pipe steam radiator. If there is any steam leakage -- and there will be -- condensate will get trapped on the radiator side of the valve, and will cause trouble. It may hammer. It may freeze and crack the radiator. It may...

Don't do it. Use a thermostatically controlled VENT, not valve, or just turn the vent upside down.