Burner Keeps Shutting Off

mikos

Hi everyone,
I have steam boiler that provides heat for pair of large tanks and burner is constantly shutting off during first hours of runs.

These are few observations I noticed so far, any help is appreciated:

1. Burner shuts off after couple of minutes when I start the boiler-maximum 0.5 bar pressure is reached. It shuts off continuously for first 2-3 hours of running, then it runs fine.

2. Pump runs until boiler is completely filled with water even it should stop when there is 70-80% level in reservoir so it is full of water most times.

3. I piped condensate trap and water reservoir, but water leaving steamtrap is pretty rusty since valve is iron made.
Similar model as this one: http://bellgossett.com/steam-specialties/traps/inverted-bucket-beartrap/
I assume this not quite good for boiler as it requires softened water.

Unit is almost new and provider/service is little help.

Jamie Hall

A bit out of my league, but a few questions to get started...

Why half a bar? Is this running to a process of some kind? If so, what?

What vents the air out of the steam mains? A bucket trap like the one you are using won't do it -- certainly not fast enough.

What controls the pump which is cheerfully overfilling the boiler? It should be controlled by the water level in the boiler -- not the level in the condensate receiver/reservoir.

If you are adding a good deal of makeup water such as might be needed with a consumptive use, things will rust unless you are also adding chemicals to control oxidation. That is not needed if you aren't adding much makeup water. Softened water may not be what you want -- probably isn't, unless your normal water is pretty hard. Softened water is remarkably corrosive.

EBEBRATT-Ed

1/2 a bar is about 7 psi. You have to find out why the boiler is overfilling with water. Normal water level is about 1/2 a glass of water. If the burner is running with the boiler overfilled you will get little if any steam.

Try posting some pictures maybe we can help. Why won't the installer fix the issue? Where are you located Canada or overseas?

mikos

Thank you for responds, I will try to answer your questions to clarify it a bit:

- Set pressure is 3 bar, but it cant reach above 0.5 bar at the few first hours.

- Air is vented only trough traps I linked, by manufacturer recommendation.
Should there be some other device for venting?

- Pump is controlled with water level electrode in boiler (by reservoir I meant boiler).
There is sight glass where you can see water level.

- Our main water is hard, this is the reason to use softener.
My concern is can rusty water that comes from system clog boiler or water level electrode.

I am in Croatia, Europe and installer keeps prolonging servicing the unit.
I will post few pictures to make it more clear.

Jamie Hall

I still don't know why you are running 3 bar as your set pressure -- some sort of process? What? That is much ohigh for just heating.

Also need to know if what you are doing uses up the steam -- a consumptive use -- or if the condensed steam is recycled to the boiler; it makes a big difference on water treatment.

That said. The bright light is your comment that after the system has been running for a while it no longer cycles, couple with your comment that it only does this on startup. This is a clue -- a big one -- that what is happening as far as cycling goes is that on startup there is a great deal of air in the system -- and you are counting on those bucket traps to vent it, which they can't do anywhere near fast enough. You do need to have some way to vent that air out much faster on startup.. The problem is that 3 bar operating pressure. There are many good, fast steam vents available, however none of the simple ones can handle anything like that operating pressure; most of them are good for 1 bar maximum, but won't operate properly even at half a bar. It may be possible to use an electrically controlled valve controlled by sensing the presence of steam at the valve -- probably a temperature sensor would be simplest.

On water treatment. Softened water is, as I noted, corrosive. If your use is consumptive, you may need to look into a reverse osmosis system for the supply feed. If not, you can still use reverser osmosis treated water, or distilled water, but should add a small amount of water treatment to it to control the pH (should be in the range from 7 to 8.5).

On the water level control. A probe is a good means for controlling, but it will need to be cleaned regularly. If it is not controlling the water level properly, that is the most likely explanation.

mikos

I run brewery and steam boiler heats 11bbl and 15bbl reservoirs.
It is self installed by manufacturer guide and 3 bar is recommended set pressure. Process runs fine when 3 bar is reached (but with burner that continuously shuts off it take forever to provide that pressure).

Also, there is no thermometer as there is on home heating system.
Steam is only used for heating reservoirs and condensation water is returned to bucket connected with boiler via pump.

I hope pictures will clear it:
https://photos.app.goo.gl/ifbC2n353eZAy2g5A

Jamie Hall

OK --Now good and thank you. Now what we need to do is to figure out how to manage the water level and how to get the air out.

On the water level. Make sure that when the water reaches the probe the pump feeding the boiler turns off -- and there should be no other feed to the boiler. If it doesn't turn off properly at that level, then try cleaning and reseating the probe (no Teflon, please!); if that doesn't work, then you may need to replace the controller.

The venting is a bit more problematic because, as I noted, the pressure is higher than most vents like Your best bet is probably to contact Barnes & Jones for their advice -- I would suggest a steam trap rated for the pressure, discharging air to the atmosphere (the Barnes & Jones Big Mouth vent may be able to handle the pressure; if not, they can come up with something -- they make steam traps up to 250 psi rating -- your 3 bars is only 45 psi or so). They might also suggest a float and thermostatic trap system rated for the pressure.

EBEBRATT-Ed

I don't think venting is an issue. looks like the condensate come back to an open tank

mikos

Thank you very much for your help.

Pump is purged from air, and there is no other water source on boiler except this pump so I assume that electrode is causing problem.. but I may be wrong.

As for condensate, it is returned to open tank. This hot water is feeding the boiler when it returns from brewery reservoir jackets.

Here are some more pictures of burner and level electrode, I hope that could help:
https://photos.app.goo.gl/dyMkGF5gBNHzU5wj6

EBEBRATT-Ed

I would suggest removing and cleaning the probe

STEVEusaPA

Can we get make/model number? Is this a yanoboiler with a Sennisi burner?