Blowing Hoffman 45 Main Valve

colonelcasey

I noticed a large amount of condensate on the wood paneling surrounding my main line vent in the basement. Seems that when the boiler in my one-pipe steam system is on, the main line vent starts spitting out air, water, and eventually steam instead of staying shut. The main line valve is a Hoffman 45. The other radiators in my house are a mix of VariValves, Gortons, VariVent, etc. I've opened up all of my vents and opened all of the intake valves to the max but the main line valve keeps spitting out water/steam/air. I brought the water level in my sight glass back down to half (it was a little high before) and cleaned out the LWCO drain valve but nothing has helped so far.

Do I just need a new Hoffman 45 valve for my main line vent or is there something else going on with my system?

Edit: Added a picture of the main line vent in question.

Captain Who

How long has this been going on? I'm sorry but it just seems to me like a pretty poor location for a vent. All that condensate is probably splashing right into the vent. I think it needs to be located up on the end of the main. If that elbow were changed to a Tee you could have the vent on an antler at the top of the Tee and the bottom will go down into the return.

Fred

It is probably a Hoffman 75 Main vent. i don't think Hoffman has a #45. It sounds like the vent is stuck open. You can take it off (with power to the boiler shut down so it doesn't come on) and either soak it in vinegar and wash it out or you can put a new one on there. Almost any Plumbing Supply will have them or you can buy them on ebay> If ebay, buy only new ones. If that one Hoffman 75 is the only vent on that steam Main, you almost certainly need additional venting to get better performance from your system.

EDIT: I did find the Hoffman 45. It is a Convector vent but that certainly is not enough venting for a Steam Main. It looks like you don't have room for the Gorton #2's and I'm not sure you have room for Hoffman 75'S. You may be able to install multiple Gorton #1's. In any case, you should go up higher than where that vent is.

nicholas bonham-carter

You definitely need more venting than you have now with that old vent, and you need to check your pressuretrol and pigtail for correct operation. a good low pressure, 0-3 psi gauge, showing ounces of pressure will give more accurate information than the 0-30 psi standard, required gauge. start with at least one Gorton #2, and work up from there, (1 Gorton #2 will vent 20 feet of 2 inch pipe).--NBC

colonelcasey

I just bought the house so this is my first heating season here. It wasn't so bad earlier in the season with just a little bit of water coming out now and then but it's almost constant now. That's why I have that little cover on because it's starting to affect the wood paneling in the basement.

I confirmed that the existing vent valve installed is a Hoffman 45. Would a Hoffman 75 or a Gorton #2 be able to screw directly onto that fitting?

Fred

The 75 will fit in that existing fitting (3/4").
You will need to install a bushing in the fiting to take it down from 3/4" to 1/2 for the Gorton 2. The question is do you have enough head room to install either? The Gorton #2 is about 7-1/2 inches tall. The Hoffman 75 is about 6 inches tall. The Gorton 1's are 3-1/2 inches tall. Again you will need multiples of either of these depending on the length of that Main.

BobC

How long is that main, you may need more than one vent and if you use that location you should extend the pipe out about a foot making sure you have slope so water finds it's way back) so the vent has some isolation from any water slugs.

The Gorton #2 is about 6-1/2" tall and has a 1/2" thread.

Bob

colonelcasey

This is what my pressuretrol and pressure gauge read right now. Thermostat reached temperature and has been off for nearly an hour. Any issues here? I might look into getting that 0-3psi gauge since this one only goes up a little to 0.5 psi when in operation.

colonelcasey

The supply main extends for about 15-20 feet from my boiler to the point in my first picture. Then there's three take-offs that go up to the first floor radiator and two second floor radiators. In my first picture, the larger diameter pipe is from my boiler and the smaller diameter pipe goes down and back to the boiler.

Edit: I need to check my headspace to see how much room I even have. Probably won't be very much since the wood panel ceiling is really close by. Barely an inch now with the existing Hoffman 45 in place.

Captain Who

The pressuretrol is set really high at cut-in of 2psi. What is the differential set to on the wheel inside the unit? I assume it is additive differential. You need to dial the pressures down to cut-in 0.5 and differential 1.0 (if additive diff). Make sure the pigtail is not clogged at all.

Fred

Yes, that dial on the front of that Pressuretrol is the Cut-in Pressure and should be set at .5PSI. it looks like it is at 2PSI.
It is adjusted by the screw on top of the Pressuretrol.
Take the cover off of the Pressuretrol (screw at the front, bottom, center and you will see a white wheel inside. That should be set at 1PSI. That will give you a cut-out Pressure of 1.5PSI which is plenty. The Empire State Building runs on about 2PSI. As a matter of maintainence, you shoould take the Prerssuretrol off and take the pigtail off (the looped tube under the Pressuretrol and clean it out. They get plugged up with gunk and the Pressuretrol can't see the boiler pressure when that happens.

Fred

colonelcasey said:

The supply main extends for about 15-20 feet from my boiler to the point in my first picture. Then there's three take-offs that go up to the first floor radiator and two second floor radiators. In my first picture, the larger diameter pipe is from my boiler and the smaller diameter pipe goes down and back to the boiler.

Edit: I need to check my headspace to see how much room I even have. Probably won't be very much since the wood panel ceiling is really close by. Barely an inch now with the existing Hoffman 45 in place.

If that is the length of the Main, 1 Gorton #2 will work OR 2 Hoffman #75's or 4 Gorton #1's. You can build an antler using 3/4 inch nipples and Tee's and elbows to mount the multiples at that same location.

Captain Who

"I need to check my headspace to see how much room I even have. Probably won't be very much since the wood panel ceiling is really close by. Barely an inch now with the existing Hoffman 45 in place."

Varivalves wouldn't be my preference but they are arguably almost equivalent to a Gorton #2. If you made an antler that goes up almost to the ceiling, you could put 2 or 3 straight varivalves, oriented horizontally. They are very small and might be the solution here, or at least worth a try because they are much cheaper per CFM than the Gortons. They also open back up at a higher temp than the Gortons (around 160 F vs 130 F).

BobC

If height is an issue you could use 2 or 3 Gorton #1's which are a lot smaller. I assume there is more than one steam main, if so how long and what kind of vent on it. You have to keep the venting balanced for good operation.

Bob

Jamie Hall

Absolutely the first thing to do is to get that pressure down. As has been said, turn the cutin down to 0.5 psi -- which is as low as it will go. That's half your problem right there.

That said, a vent in that location is going to be a problem, almost no matter what you do. Think about it: the condensate from the steam main comes sliding down that sloping nipple, then across the horizontal. Then, if any air is blowing out the vent the water will just get carried along and up... and sprayed out. With zero headroom there, I'm honestly not sure just how I would pipe that puppy. If I have a bright idea I'll come back on and post it.

Captain Who

That pigtail is oriented incorrectly, for the design of pigtail you have. It is designed to be screwed into a horizontal bushing, not vertical. I would purchase a 360 deg pigtail instead of the 270 deg one you have there.

The one you have is not protecting anything due to the fact that it cannot pool up water like a p-trap in a sink drain does. The only protection is due to the length of the pipe.

colonelcasey

I changed the main scale down to 0.5 psi. Not sure about the differential knob though. Currently, the 1 is right side up facing me. Is that the correct setting for the pressuretrol?

colonelcasey

Captain Who said:

That pigtail is oriented incorrectly, for the design of pigtail you have. It is designed to be screwed into a horizontal bushing, not vertical. I would purchase a 360 deg pigtail instead of the 270 deg one you have there.

The one you have is not protecting anything due to the fact that it cannot pool up water like a p-trap in a sink drain does. The only protection is due to the length of the pipe.

You're talking about the pigtail that contains the pressuretrol and pressure gauge on my setup? Should I change it so it looks like this instead?

Captain Who

Yes. Bingo.

colonelcasey

Just a follow-up note, I found another main vent valve on the rear part of the basement (separate from the main pipe in the first pic) that has a Gorton #1 on it. This one T's off the main and is connected to a dead-end riser pipe that goes about 6" above the main.

I'm thinking the best way to solve the blowing steam problem is to just buy another #45 for now and just replace it so at least it's not blowing water everywhere. I'll figure out a more effective venting solution once the heart of winter is over and have more time to fiddle with alternate vents/pipes/antlers for a more efficient setup.

BobC

How long is this other main? The Gorton #1 has more capacity than the Hoffman, you want the mains vented so they fill with steam at about the same rate.

Bob

colonelcasey

The rear steam main is a shorter run since it's closer to the boiler. I'd say about 10-15 feet long.

Does the Gorton #1 vent also fit the same fitting as the Hoffman 45?

BobC

The Gorton #1 has a 1/2" female thread and a 3/4" male thread. It seems you now have a higher capacity vent on the short main than you do on the long main, that can cause an imbalance in the system.

Bob

colonelcasey

BobC said:

The Gorton #1 has a 1/2" female thread and a 3/4" male thread. It seems you now have a higher capacity vent on the short main than you do on the long main, that can cause an imbalance in the system.

Bob

That's probably right because I have noticed the back of the house heats up slightly faster than the front of the house. Not by much though. Both sides are equally hot after a 10-15 minutes.

I'll just replace the main vent in the front of the house first so it stops sputtering all over the place and then work on balancing when the heating season starts to wind down. Don't want to get too crazy while it's freezing outside.

Steamhead

I'd start by putting your Gorton #1 on the longer main, and a Hoffman #4A on the short one. Those are pretty short mains so this setup should vent both quickly and evenly. You can always tweak them later if needed.

nicholas bonham-carter

Look for a location close to the end of the dry return just before or after the drop down to the wet return. As the pipe slopes down, there may be more headroom.--NBC

colonelcasey

I was able to cancel my order for a Hoffman 45 and replaced it with a Gorton #1. The height looks to be about the same as the Hoffman 45 so clearance shouldn't be an issue. I'll get it tomorrow so hopefully I can install it and resolve the blowing steam/water issue for the rest of the season.

colonelcasey

I installed the Gorton #1 valve to replace the Hoffman 45 on my main line vent yesterday. So far, after two heating cycles, I haven't seen any problems with water or steam hissing out of the main line vent. The main also seems to heat up a little bit faster than with the Hoffman 45. Still not as fast as my rear main but it's an improvement from before. The water levels in my sight glass have also stabilized during the heating cycle. It was fluctuating a fair amount with the Hoffman 45 and before I brought down the cut-in pressure. Hopefully this Gorton will last a while so I won't have to do this again!