How "fast" is Hoffman 40 radiator air vent?

lzr0

Hi,
Is it slow or fast? What approximate number of Hoffman 1A (adjustable) or Gorton sizes it corresponds to?
Thanks.

Gsmith

See this excellent reference by Gerry Gill and Steven Pajek available on the System Help Center of the Main site, and at this link: https://heatinghelp.com/assets/documents/Balancing-Steam-Systems-Using-a-Vent-Capacity-Chart-1.pdf

Appears to be midway between the 2 and 3 setting on a Hoffman 1A , or mid-way between the fixed Gorton 4 and Gorton 5 vent rates.

My experience has been its a nice vent which makes balancing the radiators and room temperatures easy.

Gsmith

Revise that last comment, I meant the Hoffman 1A makes the balancing and adjusting of room temps easy, not the #40.

lzr0

I understood, Gary, thanks.

lzr0

Gary Smith said:

See this excellent reference by Gerry Gill and Steven Pajek available on the System Help Center of the Main site, and at this link: https://heatinghelp.com/assets/documents/Balancing-Steam-Systems-Using-a-Vent-Capacity-Chart-1.pdf

Hi again. This chart does not list Verivalve. Do you happen to know how it compares to the slowest vents (like Gorton 4) when it is in Closed position? I am trying to find the slowest one.

Fred

Most people tend to stay away from the Heat Timer Varivalve. They tend to spit water. The Hoffman #40/41 are about the slowest radiator/convector vent @ .042 CFM for the #40 and .058 CFM for the #41 both at 1 ounce of pressure.

Gsmith

I thump know the Hoffman 1A variable vent at the lowest settings are about the slowest vents, I use them, and they have the advantage that you can increase the vent rate from very very slow to faster if you need to.

Fred

Gary Smith said:

I thump know the Hoffman 1A variable vent at the lowest settings are about the slowest vents, I use them, and they have the advantage that you can increase the vent rate from very very slow to faster if you need to.

That's true. I use them too but for the most part in the mid range. I was looking at non adjustable vents.
Here is the venting rate for the Hoffman 1A at each setting and @ 1 Oz., 2 Oz and 3 Oz of pressure

Hoffman 1A Setting 1 0.020 0.026 0.033
Hoffman 1A Setting 2 0.026 0.043 0.056
Hoffman 1A Setting 3 0.100 0.158 0.200
Hoffman 1A Setting 4 0.108 0.160 0.210
Hoffman 1A Setting 5 0.140 0.220 0.290
Hoffman 1A Setting 6 0.145 0.225 0.300

BobC

The Hoffman 1a is a good vent but the slop in the adjustment makes it difficult to know whee they are really set at

Bob