I found the limit for undersizing steam supply piping on my boiler

STEAM DOCTOR

For what it's worth, when I get a call about any sort of uneven heating, banging...... my first response is to tell the customer to have the boiler properly cleaned. Which should really be done regardless and very often solve the problem. My maintenance includes, removing and cleaning and inspecting all the safety controls, gas pressure test and combustion analysis, cleaning the burners if necessary.. And thorough cleaning. Which means dumping a bunch of eight way into the boiler and letting the boiler run. Typically breaks up a lot of sludge. Pumping out and refilling the boiler multiple times, until water comes out clean. This cleaning in and of itself, will often make significant differences.

ethicalpaul

https://forum.heatinghelp.com/discussion/comment/1884250#Comment_1884250

I can totally understand this kind of conservatism and caution. I have a friend where I have been trying to get their water in good shape for a couple years now, it's not easy!

I guess I am talking about the many times a homeowner comes to this forum complaining about things that seem like carryover (diving water level, squirting vents, water shooting out of main vent, etc). That homeowner comes here either unable to pay a professional, or more likely, unable to find a professional who can actually fix their problem.

Should we point them to paying thousands of dollars to correct some deficiency in their piping, or should we advise them how they can work to correct their water quality issue? Especially since we know that re-piping work can result in even more carryover if the contractor doesn't know the importance of skimming?

But mostly I'm just putting information out there that I think wasn't out there before. Take it or leave it! 🙂

STEAM DOCTOR

Should definitely start with boiler water cleaning. Unless piping is really egregious.

STEAM DOCTOR

Boiler cleaning is a fraction of the price, should be done regardless, and will often solve the problem.

pedmec

I do agree 100% with your water quality playing a huge factor in system performance and carryover. I learned that the hard way trying to figure out a 64 unit two pipe steam issue. They had a chemical treatment of the boiler water and the water was crystal clear. Almost too clear. But for the life of me I couldn't understand why I had sloshing sounds in my returns. One day separated the header drip with the boiler running and it turned out there was so much water in the header it was getting tossed into the supply like an open faucet. I came to the conclusion that it was the chemical feed pump adding too much chemical and just by luck the chemical feed tech came into the boiler room on the day of discovery. He stated that the boiler water, due to the action of the chemical which is clumping the TDS together, needed to be flushed once a week from the M&M 150 just to lower the TDS. I asked him if he is adding to much chemical as the order is so strong you smell it out of the boiler feed tank. After much discussion he lowered the feed rate and the maintenance would blow out the 150 as instructed and we have a steady water line for about 7 years now.

tim smith

Paul, cool to see your experiments. Here is a portable boiler set up with pyrex piping for the near boiler piping for a test boiler. I swear one of the members hear did same with Slant fin # of years ago but could not find. Here is link

https://www.youtube.com/watch?v=wWxRkIHTV4k

Paul, one question when you were doing prior tests with bit larger pipe that you were not seeing carry over on. Would it not make a difference in connected radiator load as flow rate increased in main piping the rate would increase in boiler outlet piping and tend to increase carry over issues. Just wondering?

ethicalpaul

Thanks Tim!

Are you asking if increasing the radiation load could increase the flow rate in the boiler piping resulting in more carryover?

For a residential system, the radiation load would not increase very much (I suppose if a TRV opened it would a little).

Here is where I could see that happening (and this is what they did with the Weil-McLain unit above, but they did it by throwing open the valve all the way open).

1. You have a small radiation load due to let's say a closed zone valve (resulting in the boiler being oversized for the connected load at that time)
2. You build up some pressure (let's say like 5 psi) — pressure will build due to the small radiation load
3. That takes the boiling point to 227F
4. Then the zone valve is opened, resulting in like two times the connected radiation suddenly
5. The pressure in the system is then lowered suddenly resulting in a lower boiling point a lot closer to 212F
6. That makes the water in the boiler flash to steam very quickly which could result in carryover

Is that what you are referring to? If not, let me know I misunderstood and I'll try again 🙂

STEAM DOCTOR

That Weil Mclain video is pure entertainment. No educational value at all.

Eastman

Are these glass pipe viewing segments expensive? I wanna see this on every installation now.

ethicalpaul

No they are quite reasonable and very solidly built. Dernord is the good brand but even the off brands are good.

You have to buy the NPT adapters for them too, but then you have the equivalent of a union, so it makes pipefitting very easy.

https://www.amazon.com/DERNORD-Line-Sanitary-Straight-SUS316/dp/B075JBJQ1Y

https://www.amazon.com/DERNORD-Sanitary-Threaded-Fitting-Ferrule/dp/B07F8P3ZW6