Is 6psi steam with no vents a problem?👀👀

Oh boy- where to start…………..

Especially where a return tank and pump is used, you need traps. I'm guessing there is likely a large trap where all the returns go into the boiler-feed pump. That's wrong. You need a trap on each drip so steam will not enter the return lines. These returns are not large enough to handle steam, and often will bang when someone uses a "master trap" at the tank.

Now….. assuming all these returns slope down to the tank, you can vent the mains through them. You'll need an F&T on each drip, and on longer mains a crossover trap as well to add venting capacity. If you're using an H-pattern F&T such as this Barnes & Jones:

https://barnesandjones.com/wp-content/uploads/2024/02/Float-Thermostatic-2000-H-Series-125-psig.pdf

you can use the extra tappings to mount a Big Mouth so it will pass air into the return, which saves some piping work.

Once everything vents out properly, you can grab the pressuretrol and CRANK IT DOWN!!

Where is this job located?

@AndythePlumber said "Steam regularly dumps out the reservoir overflow."

Now we know why the boilers don't last. With all that steam leaving the system, you need a lot of fresh water coming in to offset the loss. That much fresh water will rot out the boiler quickly.

Agree with @Steamhead 1000%. Steam out the boiler feed tank vent means a ton of MU water. It will rot the boiler and all the boiler feed piping (maybe the tank and pumps as well) and it will rot a boiler very quickly.

I have a customer with a 2 pipe Webster system if I remember correctly. The house has been added onto multiple times. There are F&Ts at the mains and steam traps at built in convectors. The only vent on the system is the wide open vent on the condensate pump. Recently moved the pump for another addition where they dug out a deeper basement adjacent to the pumps old location. Still works like a charm. You sure steam isnt just blowing throw traps into the boiler feed pump? Especially since its cranked to 6 psi...

@AndythePlumber , I wonder if @Mad Dog_2 would come up there to consult?

@AndythePlumber Do you know if the original boiler was in a pit? Sunk into the floor? Have the replacement boiler, or in this case boiler"s" been placed above the pit?

That is what RETARD means on that gauge. Once the pressure rises above 10 PSI the gear ratio changes to move the needle at a reduced rate. When you want an accurate gauge in the lower PSI increments, but code says you need a 30 PSI gauge, this is the best of both worlds.

“RETARD” means the gauge movement is damped (slowed down) so the needle responds more slowly to pressure changes. A “retard” gauge has built-in damping or other modification to:

• Reduce needle flutter
• Smooth out rapid pressure fluctuations
• Modify the arc at one end or the other end of the scale.
• Make readings easier to see and interpret
• Protect the internal mechanism from vibration and pulsation

Are those wet returns? If they go to the condensate tank and the tank is lower than the return, won't they be dry returns, unless the pipe goes up then back down.

Radiators that drop down individually to a wet return are usually 2 pipe air vent systems but those are early 20th century systems normally.

The back-pitch is the problem- those returns should slope down to the condensate tank. When that's done they will vent air as well. Then rebuild the traps and that zone should work.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ THIS ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

I have seen a lot of boiler installations that are similar to yours and most of them work pretty well. First, let me ask, what is controlling the operation of the condensate pumps? It has to be a water level control on the boiler itself. Next; looking at the picture of the 3 zone valves, they look OK but I would replace those thermostatic traps with an F&T trap, a ball valve and Y strainer before each of the traps. While you are at it I would replace all the thermostatic traps that are used on any line except those that are installed on the radiation. Now to the condensate return tank. The make-up line to the tank is controlled by a float which is part of that bushing fitting. The float level should be adjusted to it's lowest level to give the tank it's greatest capacity to store condensate water. The PRV on the make-up line should be adjusted to below 30PSI so water pressure will not push past the float valve. If possible, I would add a water meter to that make-up line so someone can record how much make-up water is being added. All of the steam traps should be checked and replaced if necessary .Any return line that is nit visible should be inspected to make sure it is not leaking and wasting water. One more item, those zone valves should have the slowest opening time possible to eliminate the possibility of pulling water from the boiler due to high steam velocity. Last item, a lot of these older steam systems need to operated a higher than what is considered normal steam pressure since there have ben so many changes to the system. (radiation and piping changes). In most cases air vents are not necessary if everything is operating properly.

6 PSI steam pressure is considered higher than normal but in this system it may be what is needed. You could try reducing the pressure gradually to see if a lower setting will work. These older systems can be challenging especially to a new service company since most of these building owners are used to repairs that are the cheapest and they are afraid to spend the money to correct all the problems.

the vacuum in the return is the water that is filling the pipe because of the bad pitch trying to get out but air can't get behind it because it is filling the full cross section.