Lochinvar Knight kettling?
Visiting my sister for Christmas. She had a Lochinvar Knight installed a few years ago after her old Munchkin crapped out. Don't remember how long ago, but I think less than 10 years. Occasionally I hear a kettling sound from the boiler room. Wondering why. Maybe air in the system?
There is a bypass installed, but no mixing valve or throttling valve of any kind. 4 heating zones and 1 indirect DHW tank. Heating zones go to air handlers in the attic. Boiler circulator is on the return, pumping towards the Spirovent and expansion tank on the supply.
Also, there doesn't appear to be an outdoor temp sensor. LCD screen shows supply and return temps, but outdoor temp reads "none." Shouldn't there be an outdoor temp sensor for ODR to make this condensing boiler run most efficiently?
Comments
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This fellow must own Taco stock. No other explanation for that. 500W if they are all running.
"I think I will just pump water in a circle even though I have direct piping".
Yes, it should have an outdoor sensor connected for maximum efficiency.
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@LRCCBJ said:
"I think I will just pump water in a circle even though I have direct piping"
LOL, yeah. Am trying to figure out what he was thinking. I read the Lochinvar install manual, and it can be piped direct without the Taco near the boiler and without the bypass.
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if that bucket is any clue, I would guess the water quality could be an issue.
It’s not a true primary secondary piping, and is that boiler pump correctly sized?
I’d start by running a cleaner, flushing and adding DI water and conditioner
Is it connected to non barrier tube by chance?
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream1 -
The four constant speed pumps are truly ridiculous. No control of DT whatsoever. One VT2218 would have been perfect.
I believe he was "thinking" P/S. But "executing" and "thinking" are two separate operations.
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one delta p circ with zone valves for the distribution would be ideal. Delta T distribution circulators constrain the distribution to one operating condition, that is not always desirable on a dynamic hydronic system.
A variable speed boiler pump, controlled by the boiler microprocessor, can have some value to keep the boiler operating in a good efficiency range. But it too can limit temperature output when you need it most.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
I thought they shipped Lochinvar boilers with 0-10 VDC primary pump?
I don't see a union on the gas pipe.
8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour
Two btu per sq ft for degree difference for a slab0 -
My 055 Knight came with a VS boiler poump. I've heard they ship with fixed speed now??
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
Bucket is dry but has some very fine gray/black powder, almost like cement or tile grout powder. Maybe left over from the bathroom tile guy.
Yes, it's got the boiler pump that you would install for a primary/secondary, but with a bypass instead of a true primary/secondary. Not sure why.
There is some black Viega Pexcel coming off some of the zone risers. Not sure if that is barrier or not.
The Grundfos pump just ran noisily, with what I'm guessing is cavitation. Probably air in the loops.
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I just ordered a 110 KBTU Knight and it comes with the Grundfos VS pump; might be old stock.
That Taco pump furthest to the right in the pictures above looks larger than the others. It also has a big wiring box which may be one of their zoning pumps that has a transformer and relay.8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour
Two btu per sq ft for degree difference for a slab0 -
Take a water sample in a jar, let it settle overnight to see what is in the fluid.
Does that air intake piping have a drain on the low spot?
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
That's a Taco 0015 3-speed for the indirect DHW. They have that wired as a separate zone on the Taco zone controller.
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No drain on the air intake PVC piping.
This is a water sample from the return manifold drain. Photo taken shortly after drawing the sample. There seems to be a very fine gray-black sediment in the water, consistent with the gray-black powder in the white plastic bucket under the manifold drain.
I'll take another pic of it in the morning when the sediment has settled out.
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got a magnet? Stick it against that glass see if the particles stick.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
OK, this is strange. I dipped a magnet into the water and swirled it around. All the fine black powder stuck to the magnet and made the water almost perfectly clear now.
Then I wiped the magnet on my fingers and got the fine black powder as a wet paste on my fingers. It's like someone took another magnet, pulverized it, and injected the powder into the boiler water.
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it iron oxide particles, aka magnetite
Basically the ferrous metals in your system breaking down from the presence of Oxygen. Very common in non barrier tubing systems
It’s heavy and a bit tough to flush out. It lies in low sections like cast iron boiler sections, reduces heat transfer and can cause the kettling sound you hear
Similar to a tank water heater filling with sediment and making that sound Or a scaled up tea kettle 😉which is maybe where the term comes from.Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream
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OK thanks. Why isn't the water turning rust colored?
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Magnetite turns to hemitite (rust) when more O2 is added. But you don't want either in a hydronic system.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream1
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