Original 1950s Heat Timer Vent

Long Beach Ed

We're all familiar with the Vari-Vent, Well here's an original Heat Timer vent, perhaps from the 1950's, back in the days when Heat Timer was at 520 Broadway in NYC:




It claims to have an "internal thermostat" and has an adjusting knob on top marked to various indoor temperature settings. How did this thing work?

My first order of business was to take it apart. Almost. There's a set screw that retains the knurled brass knob. It's pegged with a steel plug, so it's not coming out. They didn't want anyone messing with it. A search of patents came up empty handed.

There's a single vent hole in the side, perhaps as large as a Gorton D. Through it I can spy the corrugations of a bronze bellows. It spins with the adjusting knob. And like the modern Vari-Vent, the seat is on the bottom. And that's all I can discern from this little chrome marvel.

Anyone want to speculate what this knob actually did other than perhaps bring the plug closer or further from the seat ?

ethicalpaul

Now it's a Lulu Lemon

mattmia2

Probably 2 bellows, one set for steam, one set for room temp. Room bellows closes vent if room is at temp, seam bellows closes vent when steam reaches it.

Long Beach Ed

mattmia2 said:

Probably 2 bellows, one set for steam, one set for room temp. Room bellows closes vent if room is at temp, seam bellows closes vent when steam reaches it.

You're very clever, Matt... Looks like there might be room for that...

Big Ed_4

I like it , to make it work properly I vision a insulater between the vent and TRV .

Long Beach Ed

I really wonder how responsive the thing actually was. I'll replace a $ 200, five pound Honeywell TRV with it and see what happens. Hard to believe anything could be at all sensitive to 60 degree air temperature when it's 1/8" away from 210-degree flowing steam in the same housing. I think it's mostly marketing fluff. Maybe I'll find another one and cut it open.

mattmia2

as i think about this more, it may just be set for room temp. If it is open when the boiler starts the radiator fills with steam, the vent gets hot and closes, it probably gets to the desired room temp around the time the steam gets to the vent anyhow, the radiator heats until the boiler stops. If the room is at temp when the boiler starts, the vent is closed from the room temp and the radiator doesn't heat. If the room cools with the cold radiator while the boiler is still firing, the element opens, the radiator vents, the radiator starts heating. Remember, the vent can only keep the radiator from beginning to heat, it can't stop it once it is heating.

reggi

Put away the saw  😂

Long Beach Ed

Haha, Reggi ! You beat me to it! Thank you!

What held it together? The pointy indexing pin?

So all this knob did was lower the bellows closer to the seat, venting faster or slower? Hahahah! Where's the precision thermostat?

mattmia2

It doesn't vent faster or slower, it changes the temp at which it closes.

Long Beach Ed

How? The steam hit it, the bellows extend. The dial moving them up or down 1/8" does what?

Chris_L

The text in the attached photo says the port of the valve will get larger as the room temperature drops below the dial setting. (Unlike other adjustable valves the numbers on this one are in the range of room temps.)

So it sounds like the valve is supposed to increase the port size in proportion to the delta T.

mattmia2

They close when the steam hits it or when the room temp is above a certain point. Once the steam is there they don't need to open again until the room is cold. Remember once the radiator is full of steam the steam condensing pulls more steam in.

The screw adjusts what temp that closes and opens at. It will be in the room temp range.

If the room is already warm enough, the bellows are closed when the cycle starts so the air can't vent, the radiator stays cold, when the room gets colder, the bellows open. It the boiler is still on, the radiator starts heating.

reggi

I think it was just a gadget, Long Beach Ed said:

Haha, Reggi ! You beat me to it! Thank you! What held it together? The pointy indexing pin? So all this knob did was lower the bellows closer to the seat, venting faster or slower? Hahahah! Where's the precision thermostat?

I don't remember ..  your picture with the box reminded me I had a similar one and when I found it it came right apart..
I might of gotten it that way because I don't have a one-pipe system and wouldn't of need it functional... I'm not sure if there's anything missing..
I'll take a closer look 

mattmia2

Looks like there is a roll pin driven in to the side of the main body that allows it to only turn one revolution, if you drive that out you can unscrew it.

Long Beach Ed

That's a pin of sorts, but not a roll pin. The outside of it serves as a pointer for the dial. It's machined brass and pointed, so it would be difficult to pull out. They made these things difficult to take apart.

The dial raises or lowers the bellows one revolution, maybe 3/16"...

So when the temperature was set to 75 the venting was faster until steam closed it. When it was set to 55, the venting was slower until steam closed it. Is that how it, eh, worked. There was no "thermostat". The bellows reacted immediately (probably at about 150 degrees) when steam hit it. What varied was the venting, and that varied with the knob setting.

Those Heat-Timer guys must have been from Brooklyn.

Same bellows as today's Vari-Vent by the way. Wonder if these got unglued and fell into the seat too.