Updated steam parts, now worse than before

Vito Cavallo

I replaced my old main vents per instructions from the very knowledgeble and helpful people on this board. I have a one pipe system.

I also replaced my old Dole 1A steam vents with brand new Hoffman 1 vents. I even turned my pressure from 3 PSI down to 2. The only thing I have not done was insulate my 2.5" main pipes.

Now, some radiators do not get hot, and it seems some of the radiators do not radiate heat as strongly as before. I have removed some of the Hoffman vents, and drained the water from them. This seems to solve the problem for a short term. The old system took a while to heat, but it worked great.

What could be the problem? Are the Hoffmans defective or not adjusted properly? The first floor vents are dialed into 4 and the second floor vents are wide open.

Thanx

Mark Eatherton1

Inadequate pitch...

You're dealing with one of the simplest forms of steam heating. It is not uncommon for the radiators to chew their way into wood floors, causing the radiators to be either pitched flat, or actually running backwards. Try taking some checkers, and lifting the end opposite of the steam connection, then insert the checkers under the legs so as to elevate the end of the radiator to allow the condensate to freely flow back to the supply main. Also, make sure all radiator valves are either wide open or completely shut. Any atempt to throttle the radiators with these valves will cause problems

Once things start working again, you may have to consider the use of one pipe non electric thermostatic temperature controls. They will shut off steam to the rooms that are too warm and divert it to the rooms that are too cool.

Also, get the lines insulated. It wil make a world of difference in teh performance of your system.

ME

Vito Cavallo

Thank you for the response

I did raise one of my problematic radiators, but the problem still appears. The valves are fully open.

The big question is why all of these new parts made things worse. Can I increase the pressure back to 3 psi?

Steve_35

More pressure is not better

Mad Dog

Bottom line, Vito...........................................

and, I have learned the hard way to tell people BEFORE I touch their system that ANY!!!!!!!!!!!!!!!!!!!!! Change you make to a steam system Will change its behavior. Don't go backwards, the changes you have made a good,but you need to keep going. How is the boiler piping? cleanliness of water...what kind of main vents and how many? Mad Dog

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Mad Dog

Also, this is why some jobs are too much for most DIYs

I don't know if you are a contractor or not, and I will try to help you regardless, but getting a steam system working right is a lot harder than many imagine. It takes years of getting beat up on these jobs before one gets reallllll good. It may be time for a steam pro to pay a visit. Mad Dog

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Vito Cavallo

I will give it one more shot

I will give it one more try by insulating the mains and raising and adjusting the rad's. Then, I will call an expert.
The parts I replaced were very old and probably needed replacing anyhow.

The good thing is that spring is coming up soon.

Thanx

Fred Harwood

Venting

and mains insulation are critical to your system. For more on balancing by venting, see for example:

http://www.bellgossett.com/Press/balancing.html

Adding a pair of 75s, or Gorton #2s, always helps. You cannot vent your main fast enough (in a parallel-flow, single-pipe).

Vito Cavallo

The main vents

are above the boiler, not at the main ends.

Should I move them? Someone here responded that they built them like that sometimes. I have a Hoffman 75 and a Hoffman 4a as my vents.

Looking for insulation today.

Thanx

Fred Harwood

Main vents

In a one-pipe steam system, the main vents should be at the end of the main, about 18 inches before the drip to the wet return. Tell us more about those vents near the boiler. Mains should be vented to just past the last riser on the main, and then big time as well.

Steamhead

Also

measure the length and diameter of each steam main and tell us which vent is on which main. We can tell you if they are sized properly.

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Ralph Blaine

I am not a pro. Just a homeowner that likes this site. In your text you note that you were shaking water out of your rad vents (Hoffman 1A). According to Dan's book (The Lost ARt, page 106 to 109) the 1A vent has a dropaway pressure of 1.5 PSI. If you have your system set at 2 PSI then the 1A will have a hard time opening back up after each cycle and so when the next run of steam comes it won't be able to enter the rad because the valve is still closed. Dan's book recommends a cut-in pressure of 0.5 PSI on one pipe systems. That's what I did. I also replaced my Hoffman 1A's (which were also filling with condenstate) with Gorton vents. These two steps turned a radiator which was only getting hot occasionally into a reliable performer. I think the Gortons must have a higher drop-away pressure (they work on a different principal I think) - I think they are great vents.

That's my two cents worth.

Bob C

Vent Location - Same Setup

I have the same setup as Vito where the vents for the mains are above the Boiler on the dry return. I was told this was okay? How beneficial would it be for me to get the vents moved to the end of the mains?

Vito Cavallo

I am glad someone had this problem. I just spent over $150 replacing all of my vents. If my insulation does not fix this problem, I guess I may need to replace my vents again. Bummer.

Dave Meers

all is not lost

Hi Vito,

Take a deep breath. OK, what it sounds like you have done so far is all positive. MAD DOG is right, it is better to step forward than back. Steamhead needs some info on the mains. Get back to him with yours. Venting is very important with one pipe. The location of, venting capacity of, and number of vents, main and radiator are crucial to top performance.

Insulation is probably the best bang for the buck on a steam system, other than cranking down the pressure.

Take these steps: 1) verify vent capacity and location

2) verify pitch of all piping & rads

3) operate at lowest pressure

4) insulate all supply piping

5) have a pro do it or guide you, they
are worth it.

6) always suspect a dirty boiler

Best regards, Pat

Bob C

Well, not exactly.

I am not having any major problems. Just trying to fine tune the system to get the house heated more evenly. I was reading your post and the location of the vents got me curious since I have the same setup.

I am also a homeowner, and just spend 200+ dollars to put new vents on all of the radiators. It did help me a ton. I have my mains insulated, so I am still betting that has a lot to do with your problems. I have had my house for 6 years now and it seems like I need to change the vent setting slightly every year. That is why I am here, to read and learn.

Bob

Vito Cavallo

The mains are about 20 feet and 12 feet, not including the 2 or 3 feet for the risers.
Diameter is 2 1/2.

Thanx

RonWHC

I think Ralph

nailed it. Drop the pressure. The 1-As can't do their thing @ 2#.

Unknown

Pipe insulation

That seems to be the biggest problem

Noel

Steamhead

Try upgrading

go with two 75s or Gorton #1s on the long main and one on the short one.

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jeff_50

Several of the pros here have mentioned the
importance of the location of the main vents.
Most things I've read say that the main vents should
be back from the end of the line between 12 and 18".
Why? Or rather what are the benefits of doing it this way?

On my old one-pipe system, the main vents are right
at the end of the line directly above the drip return. The system runs run fine and I have no water hammer.

Just curious.

JC

Fred Harwood

End of main vents

usually are installed away from the turbulence and spray of condensate hitting the el before dropping into the return. It's just a way of helping them stay clean and avoid hammer. Smaller systems that build little pressure and just trickle condensate into the return have few problems even when the vent is mounted on the drop. I still like to get them up off the el a foot or so, if only to let them cool more quickly and reopen between cycles.