Is there ever a reason to maintain higher water level than NWL in spec book??

JUGHNE · February 2018

Looking at 2 Independence SIN8LNS-LE2 boilers connected in tandem/parallel.
Installed in 2002. Installer was very competent and would follow instructions and piping diagrams.
There were no piping diagrams for tandem connections included with the boilers.
He had to depend upon supplier/factory advice.

Each boiler piped with both 2" risers into 3" header with 2" equalizer.
Each has 3" supply main riser drop headed into 6" header which has two 3" steam mains connected.
6" header has drip with F&T going to dry return. All connections are in the approved arrangement/order by the book.

One feeder pump for both boilers.
Each boiler has M&M 150S-MHD LWCO/ pump feeder control.
Solenoid valve for each boiler water fill from pump.
Each boiler has probe type secondary LWCO.

However........the pump feeders are mounted with the casting line at the level of the recommended Normal Water level.
This is 2" higher than recommended by M&M, boilers are constantly over filled.
Installer was told by supplier/factory reps to install them at that height.
Any idea why??

The system runs at less than 1 PSI. The same reps said he needed to raise the pressure by installing King valves on all 4 boiler risers and throttle them down. Anyone ever heard of this??

It has been heating the building and is in need of basic servicing now.
I believe lower the feeder controls would improve the steam delivery.
There is very little steam chest with this water level.

New England SteamWorks · February 2018

JUGHNE said:

The system runs at less than 1 PSI. The same reps said he needed to raise the pressure by installing King valves on all 4 boiler risers and throttle them down. Anyone ever heard of this??

Find someone else.

New England SteamWorks · February 2018

JUGHNE said:

It has been heating the building and is in need of basic servicing now.
I believe lower the feeder controls would improve the steam delivery.
There is very little steam chest with this water level.

Very plausible.

EBEBRATT-Ed · February 2018

I would try lowering the pump controls. Sounds like he did a good job with the piping.

Had a job a few years back with two boilers and the engineer undersized them a decent sized school. They were piped right and had been skimmed and skimmed. When they had steam pressure on the gage they were fine.

With 1 boiler on on a cold start you couldn't keep water in the boiler, surging and tripping low water. What I figured was as soon as the 1 boiler started making steam into the building all the piping was stone cold, this cause the steam to collapse making a vacuum in the system. This pulled steam and water out of the boiler and made an unstable water line. They had an electronic pressure transducer on the steam header. As soon as that thing went +.02psi the boiler was fine.

I ended up throttling the gate valves in the steam coming off each boiler and it "got by"

JUGHNE · February 2018

Thanks for the interest. This was installed in 2002.
This is a church that the installer is a member of, I am sure he donated more time and treasure to this project than he ever intended to. It pretty well swore him off steamers and most older CI HWH. He refers most of these jobs to me......as few of them as there are in the area.

The supplier/reps are 220 miles away, but as we all know in the rural area that anyone that far away, from the big city and sounding as if they are in the know of all things are to be believed.....sometimes. As one ages and you know what questions to ask, you see thru the BS smokescreen......(just get off my phone and don't call back

)

Ed, thanks for that info. That is an interesting concept, it should be a note of interest for the library here concerning tandem boilers.
This install has both boilers connected to 1 tstat.
I have wondered about shutting one boiler down after temp is reached. I will keep your story in mind if it comes to that experiment.
All emitters in the church are fin tube. This is a good lesson in how much better CI is for steam. Another church with CI I have the setback happen shortly after services start and with the added people BTU the building will coast thru to the end.
I see not to do this with the fin tube.

ChrisJ · February 2018

Increasing the pressure decreases size of steam bubbles and will stabilize the boiler according to the commercial boiler videos I've seen.

Those aren't for low pressure steam heat though....

Is there ever a reason to maintain higher water level than NWL in spec book??

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