Lochinvar Solutions clogs with 'soot'

Jeffthearchitect

I have a reasonably new Lochinvar Solutions boiler - for heating my 1940's 1,000 square foot home (in slab heat). EVERY year I pay hundreds of dollars to have it cleaned (it stops igniting) . It is absolutely loaded with what I will call 'soot'. The boiler gets all the combustion air it could possibly need (it is in a open room) and has a new exhaust (with motorized vent damper). The boiler is a 'rebuild' - the boiler I bought leaked (at the sweges(sp?) between the fin tubes and the tanks) Lochinvar was adamant this could not be happening and did not want to replace - they finally agreed, albeit reluctantly, when it became obvious it was leaking - the agreed to replace the unit with a rebuilt unit. I have the mechanical man coming Tuesday for the nasty job of dissembling the unit and cleaning. ANY IDEAS how to keep this from happening? can I post pictures to this site (I will have them Tuesday night). Buying a more efficient boiler has turned into an expensive nightmare ! thank you .

kcopp

Tell us more about the system. What do you have for radiation? How is it piped? Where is it located in the home? Is it in a wide open area or in a closet?

Tinman

He needs to check gas pressure, flame impingement, burners, burner orifices, combustion air, combustion analysis.

Is it LP or NG? Is it set up properly for the gas being used?

Jamie Hall

Stephen Minnich said:

He needs to check gas pressure, flame impingement, burners, burner orifices, combustion air, combustion analysis.

Is it LP or NG? Is it set up properly for the gas being used?

Yup. Step one is to get the unit thoroughly cleaned -- all the "soot" taken out of it. Don't just wave a vacuum at it, really clean it. It can't breathe properly if it's gunked up. Then, the whole combustion train needs to be checked and set to be right, as @Stephen Minnich said. Then it needs to be properly adjusted, which means doing it with the correct instruments -- adjusting by eye won't do it.

rick in Alaska

Any chance of backdrafting in the room? Dryer, kitchen range hood, bathroom fan, fireplace, etc? Makes me wonder if it is why it is sooting up.
Rick

JUGHNE

How about the temp of the return water?

Tinman

@JUGHNE - I could see flue gas condensation then, but sooting?

Zman

@Jeffthearchitect
You have received some very good feedback here.
Please post pictures of the installation and any info you have about combustion analysis you may have.

I think the idea that all the combustion you will ever need can come from the space is a common misconception and is deeply flawed. It assumes leaky construction which often does not exist in today's tight building envelopes. The combustion air cannot come from the space without being replace by air leaking into the space (from the outdoors). This negative pressure is often very undesirable from a building science point of view.

delta T

The solution has a 2 stage burner, BOTH high and low fire need to be checked for the proper manifold pressure stated in the instruction manual, and a combustion analyzer needs to be used to fine tune the combustion. Depending on how the control is set up, the boiler should be running on low fire most of the time. You should not be seeing any soot, and if soot is really what it is, there is a problem with makeup air, gas pressure, draught, or some combination of all three. You said "The boiler gets all the combustion air it could possibly need (it is in a open room) and has a new exhaust (with motorized vent damper)", this does NOT guaranty that there is enough combustion air. Make sure there are not exhaust fans pulling a negative pressure on the room (bathroom fans, clothes dryers, etc.)

Mark Eatherton

I've seen low mass CFT boilers connected to high mass radiant systems "sweat" on the heat exchanger, drop condensate on the burner, fouling the burn, causing carbon deposition on the HXer. We need more pictures and information...

ME

Zman

Mark Eatherton said:

I've seen low mass CFT boilers connected to high mass radiant systems "sweat" on the heat exchanger, drop condensate on the burner, fouling the burn, causing carbon deposition on the HXer. We need more pictures and information...

ME

Not to mention, the boilers get a bad case of dandruff.
Hopefully the OP is not a one hit wonder. This is an easy one to remedy once the cause is determined.

JUGHNE

Cold 1940 slab...cold return water...cond water raining down on burners....maybe containment air in the mix and not enough.
Like a pool heater on first startup?..
WAG

delta T

You know, I guess I just assumed this boiler would be piped correctly with injection mixing, or some other means of controlling the return temp, (I know, I know, I should know better by now) but we may find that it is piped direct to a manifold, boiler temp set at 110, and well we all know what will happen in that case. Just re-read OP's post and this popped out at me:

"I have a reasonably new Lochinvar Solutions boiler - for heating my 1940's 1,000 square foot home (in slab heat). EVERY year I pay hundreds of dollars to have it cleaned (it stops igniting)"

I'm leaning more towards bad installation causing low return temps, condensation buildup on the exchanger leading to a retarded draught which is causing the sooting. The solution heat exchanger is not particularly easy to clean thoroughly, so if the bottom is getting cleaned with a brushed vacuum cleaner attachment, and that is it, there is likely more buildup in the fins of the exchanger, which is probably now beyond saving. Of course this should be readily apparent if a combustion analyzer is used, but Solutions are also hard to tune with an analyzer because of the built in draught diverter. You have to be very judicious on getting the probe up into the diverter, and down into the gap between fins. Its not easy to get an accurate reading. And if an anazlyzer is used, but it is being probed after the diverter, then the dilution of the gas sample may make the high CO we would associate with a clogged exhcanger read as less than 100ppm.

Make up air may or may not be a secondary problem, but of course this is all speculation until we get some pics.....

gennady

You will most probably need to install 4 way motorized valve with outdoor reset and with cold water protection set at 140F to prevent condensation, or primary secondary piping. I see these problems all the time, with copperfin boilers installed without any cold water protection. All burners must be cleaned and inspected. Most likely they are already damaged.

nicholas bonham-carter

The solution has an optional outdoor reset, and a 2-speed gas valve, so presumably you cannot select too low a water temperature.
Maybe there is an unvented dryer blowing in its face.--NBC

Zman

"The Architect" is done. One post, Zero return visits.....

Mark Eatherton

Oh well. Maybe others will learn from his mistakes...

ME

delta T

@nicholas bonham-carter Crazily, I think you set the SWT down to 110 on the solution. I might be wrong, but I think you can

delta T

@Hatterasguy

Hatterasguy said:

delta T said:

@nicholas bonham-carter Crazily, I think you set the SWT down to 110 on the solution. I might be wrong, but I think you can

The I & O manual is pretty firm about staying above 140F.

Yes it is for obvious reasons, but the control goes down to 110 on the low temp setting for outdoor reset. If you are using the boiler in a low water temp situation, you are supposed to install a system sensor and a bypass kit to ensure 140+ going back into the boiler. That being said, the control will still allow you to run very low temps without the kit or system sensor installed, so someone who doesn't know what they are doing, could easily set it up wrong and cause low return water temps and all the associated problems.

captainco

Two stage boiler, indoor-outdoor reset = self destruction!! 20 or 30 degrees of water temperature is not going to make as much difference as the 1000 degree lower flame temperature in low fire.