Hoffman / Gordon cross reference?

jhosef

last winter was the first in my neglected 1920's 3-story house.



only about half of the rads were heating up and the others were whistling badly. I replaced all the vents with Hoffman no. 40's and it did something right because they all started heating up.



I just got a new boiler installed and replaced a few radiators. they did the preliminary startup when I was not at home, it was noted to my wife that several of the rads did not heat up like they should because the vents were incorrect.



The installer was feeling generous and left her with a quick schematic of the system indicating the proper sizes in numbers and letters for the proper venting. it looked alot like this: <a href="http://www.gorton-valves.com/specify.htm">http://www.gorton-valves.com/specify.htm</a> so I think he was talking about the Gordon



I do understand (now) why you vary the venting as distance from the boiler increases, but it kinda stinks to have to replace them already so I've looked all over for a cross reference of Gordon to Hoffman to see where my no. 40's fit in.



I see that Hoffman makes an adjustable vent. for the price, is this better than fixed for the flexibility in an old system?



let me know your thoughts. I'm going to contact the installer as well.



thanks.

crash2009

Radiator vent comparison

Hoffman 40 vents at .067 CFM @ 2oz

Hoffman 1A ranges from .026 (setting 1) to .225 (setting 6)

Gorton makes several sizes ranging from .040 to .540



Has anyone looked to see if you have any main vents?  If you have any, are they working?  What kind are they?

nicholas bonham-carter

main vents vs. radiator vents

i suspect your main venting is at fault here. can you show us pics of the main vents?

these do all the work of allowing the air to escape, as the boiler begins its firing cycle.

even though the gorton #2 main vents are costly, they are worth every penny to prevent the necessity of paying the fuel company to force out the air through your radiator vents, and suffering the unbalanced heat as a result.

you would also benefit from a vaporstat to keep your pressure down below 8 ounces, as the fuel company is making money on keeping the pressure above that setting.--nbc

BobC

pressure, venting, and pipe pitch

You stated some of the radiators didn't heat up properly according to the installer of your new boiler. It's hard to tell how much of a problem this is without actually having to bring the house up to temperature on a cold day. If you replace the vents on the slow to heat radiators adjustable vents will work but I've found the Hoffman adjustable vents to be noisier than the 40a. Ventrite adjustable vents are a quieter vent but they are not as widely available in some areas. Be wary of the no name vents a lot of the big box stores sell, they are cheaply made and have quality issues.



When a boiler and radiators are replaced it can knock a lot of crap loose in the pipes, make sure the system has been flushed and skimmed so the water is clean. If the water in the sight glass is not clear it needs attention



I'm assuming this is a single pipe steam system..



- What pressure is the system operating? As others have said it has to be under 2psi and it should be considerably less; it is very hard to tell what the pressure is on a 30psi gauge, you might want to add an auxiliary 0-3psi gauge so you know what the pressure is.

- Is there any banging as the system heats up, if so where?

- Is the piping to the radiators sloped so any condensing steam can find its way back to the boiler? Use a level, the eye can easily be fooled especially in an old house.

- Is the radiator sloped so condensing steam can find it's way to the steam pipe? Use a level to be sure of the slope. Are the radiator valves all the way open?

- Are the air vents on the steam mains working and are they large enough to vent the mains quickly?

- Is all the piping in the basement insulated?



This site offers several books on steam heat, they will pay for themselves many times over after you read and understand them. It's best to know what your talking about when talking to a contractor so they don't just blow your concerns off.



Please post pictures of your new boiler , the piping going ito it as well as the main vents. Good luck with your new boiler,



Bob

BobC

pressure, venting, and pipe pitch

duplicate post

BobC

pressure, venting, and pipe pitch

Triplicate!



Sorry about that!

jhosef

resizing the vents and further steps

This a one pipe system. I've got a couple of Dan's books that have given me much help on my system, but much to learn as I go along. I appreciate the info.



That said, since this post I have gained an understanding of my error in installing those Hoffman 40's all around. I get now that these are really just for systems that are even piping runs and because of my multi-floor house I need to have varied vent sizes proportional to the pipe run.



Would it be correct to deduce that if the Hoffman 40 is 0.68, I can keep this in place where I would want a #5 (0.70)?

For replacement, the Maid-o-mist appears to be the economical version of Gorton style, or are these garbage?



I suspected that their test of the system balance would be a bit inaccurate during summer weather. This was more of a leak test really. They will be back when the weather gets colder to do another test. The installer knew that I have re-vented the system last winter and knowing that I was interested in doing this myself was giving me a tip to save me some labor costs by passing me that diagram (http://www.gorton-valves.com/specify.htm).



Thanks for the checklist, a few of those items will need to be reviewed when the system is up and running, but on my "before it gets cold" task list is to finish the insulation of the pipes (just got the asbestos off). Will look at the factor the pressuretrol guage and plan to keep an eye on that sight glass as the winter progresses since they claimed to have flushed the system.



Will check the main vents, verify level of return pipes and photograph this evening.



-joseph

BobC

vents

Your right that it will be difficult to try and balance out the venting before the system needs to produce heat, a nice cool fall night would be a good place to start. Keep one important fact in mind, you want the mains to vent as fast as possible and then the radiators to vent slowly (as opposed to the main vent rate). My steam main is only about 16ft long and I have a Gorton #1 on it because they are a good fast and inexpensive main vent (0.54cfm at 2oz) and that gets the air out nice and fast.



The Hoffman 40 vents at 0.067cfm while the !A goes up to 0.225cfm at setting #6. Once heating season starts you can run around and note which radiators start to heat up first, the slow radiators probably need a faster venting rate. In general the radiators with the most EDR and longest pipe runs will need a faster vent rate. Basically you want to vent the higher volumes of air faster so the radiators will see steam at the same time. Don't worry if radiators don't heat all the way across as long as the room gets warm enough.



If you have more than one main make sure you know how fast they vent relatively. It might take a few tries to get things fairly well balanced. Be careful not to vent the radiator near the thermostat fast because that could shut the system down prematurely - the thermostat will shut off.



I've heard mixed results with the Maid O Mist vents but have never used them myself.



good luck,



Bob

jhosef

pictures

okay, I went down that checklist and took some pictures:



- What pressure is the system operating? It looks to be set at 2psi and the guage looks appropriate for the low pressure.



- Is there any banging as the system heats up, if so where? Will have to wait until fall.



- Is the piping to the radiators sloped so any condensing steam can find

its way back to the boiler? I'm assuming that you mean the return lines back to the boiler. These all now ~1/4"/ ft. Had to loosen the hanger on one of them.



- Is the radiator sloped so condensing steam can find it's way to the

steam pipe? Are the radiator valves

all the way open? Some are, some are not. What sort of slope are we looking for? Valves are open.



- Are the air vents on the steam mains working and are they large enough to vent the mains quickly? I've got an order in for a Gorton #1 and #2 for the 26'-0" and 11'-0" runs respectively.



- Is all the piping in the basement insulated? Working on putting the insulation back on to current EPA standards. By "all" does mean the piping coming right out and into the boiler (incl. Hartford loop)?



Thanks for the help,

Joseph

Rod

1 Pipe Steam Radiators

Hi Joseph -

On a one pipe steam system the radiator should be slightly sloped towards the inlet pipe as this “encourages” the condensate to leave the radiator and return to the boiler.  It’s best to use a carpenter’s bubble level to check the slope as in some cases the floor (especially in older houses) have sagged so that just propping up one end of the radiator may not be enough. I use stacked quarters ($0.25) till I'm satisfied with the amount of slope and then cut a block to that thickness to replace the quarters.  Too much slope can cause problems as this then causes the condensate to pool near the valve end and interfere with the incoming steam. Be careful when lifting a radiator as they are heavy and can be unsteady. I use a 2x4 as a pry bar with some wood blocks to help me ease one end of the radiator up.



The intake valve to the radiator has to be fully open or fully closed during operation (See attached drawing)



On the insulation- All steam bearing pipes should be insulated. One of the Wallies, "Crash" did several very good posts on insulation just a couple of weeks back so you might want to take a look at them.

- Rod

BobC

Q&A

- What pressure is the system operating? It looks to be set at 2psi and the gauge looks appropriate for the low pressure.



After everything else is working fine you might want to put an auxiliary low pressure gauge on to be sure the pressure is low, pressuretrols are not very precise. i have a vaporstat set to 12oz on my system. Problem is they don't give vaporstats away.



- Is there any banging as the system heats up, if so where? Will have to wait until fall.



- Is the piping to the radiators sloped so any condensing steam can find

its way back to the boiler? I'm assuming that you mean the return

lines back to the boiler. These all now ~1/4"/ ft. Had to loosen the

hanger on one of them.



These radiators just have a single pipe going to them; 1/4" per foot should be fine.



- Is the radiator sloped so condensing steam can find it's way to the

steam pipe? Are the radiator valves all the way open? Some are, some are not. What sort of slope are we looking for? Valves are open.



You need a slight slope so the condensing steam finds it's way back to the pipe feeding the radiator. On a level the bubble should just about touch the line. On my 2 ft level one quarter gets me to the fist line on the level, two get me half way to the second line (my level has two lines on each side of the center level position).  Rod's information is right on the money.



- Are the air vents on the steam mains working and are they large enough to vent the mains quickly? I've got an order in for a Gorton #1 and #2 for the 26'-0" and 11'-0" runs respectively.



Just for curiosities sake, what kind of vents were on there originally and what kind of shape did they appear to be in?



- Is all the piping in the basement insulated? Working on

putting the insulation back on to current EPA standards. By "all" does

mean the piping coming right out and into the boiler (incl. Hartford

loop)?



All the piping and the fittings should be insulated, do the piping first and then go back and do the fittings. It can be aPITA but be fussy with the steam exit out of the boiler and the header area, it's not cheap but it does pay off down the road.



Bob