Vitodens Inspection/Cleaning

Mike T., Swampeast MO

Opened the combustion chamber today. Photos just as seen.

2,077 operation hours (86.5 days).

Began operation 11-1-04 (143 days) so burner fired 60% of the time.

No real idea what the small amount of "stuff" inside really is. The largest pieces disintegrated when I tried to pick them up. Most of the smaller pieces quite crumbly. A few rather hard but still able to pulverize between my fingers.

Date code shows the boiler was over a year old upon purchase--maybe there was some gunk already inside.

Boiler hung without flue (didn't order the adapter) for a week or so--maybe some stuff fell in as my basement isn't exactly clean.

Only one cut in the flue line and am quite certain I cleaned it nicely. Horizontal venting with termination piece going through a fresh hole in old brick so maybe some small pieces of brick made their way in as it was pushed through the hole.

Large gravel parking lot below my house to the west and north. Nearest part about 60' away and about 15' lower. Lots of activity down there as it's the transportation and facilities maintenance hub for a university.

Natural gas here should be about as pure as it gets. Huge pipeline only 15 or so miles away and am 90% certain that it's our source.

2nd photo shows the top of the HX.

Last photo shows the burner. Sorry for fuzzy focus. It was perfectly clean.

Everything else inside the sealed portion of the boiler as clean as the day installed. No visible dust/dirt buildup on anything.

Mark Eatherton1

That is without a doubt...

the DIRTIEST Vitoxchanger I've ever seen.. Really.

ME

Mike T., Swampeast MO

It's clean now. Will be interesting to see after the next heating season. Never opened it before, so don't know if it was something already inside. Did vacuum the sealed area before shutting it up.

hr

Looks like some German

mouse turds to me

hot rod

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Mark Eatherton1

ISO DIN ISH MOUSCH TURDSCH

Now THATS a mouth full...

Actually Mike, I guarantee you that those weren't in there from the factory,and to be perfectly honest with you, I wouldn't worry about them. Probably more of an environmental intake thing than anything. The three that I pulled own after a year were immacualte, other than a very small amount of white powder coating on the heat exchanger.

I've got the factory cleaning instructions here somewhere. I'll try and post them later.

ME

Mike T., Swampeast MO

Not concerned as there wasn't much there. Vacuumed, used C.L.R. and clean white towel--less grime than when I clean my face after a day of messy work. Like you, I suspect environmental intake. Vent termination faces that gravel lot and the prevailing winter wind. When all the workers tear out at 3:30 p.m. there's a cloud of dust. The little bit of rusty water at the back almost makes me think that I left some loose burrs when cutting the flue pipe.

From the patterns of discoloration it sure looks like the water jacket at the rear (where the return water enters) sees LOTS of condensate flow.

ScottMP

Interesting

Looks like the same deposits in the munchkin.

Can we get a responce from Viessmann on this one.

Are we seeing the begining of combustion effects on Stainless Steel in the field ?

Anyone ever see this ? It would be nice to understand whats happening here.

Scott

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S Ebels

I suspect

If I had to guess I would say it's probably some sort of external contamination. Mike said the stuff was crumbly not hard and metallic like the stuff in the Munchkin post. Combustion and/or condensation residue most likely. Bear in mind that any condensing appliance will build up some gunk simply from the minerals contained in the water vapor. This is just one of the reasons that condensing furnaces and boilers need good timely maintenance.

Mark Eatherton1

As promised...

From the Office of Master James McCarthy, Vitobonics expert extraordinaire...

----- Original Message -----
From: "James McCarthy"
To:
Sent: Wednesday, October 06, 2004 1:28 PM
Subject: Fw: Vitodens Cleaning


>
> Hi Mark,
>
> The cleaning agents referred to in the Service manual fro Vitodens are
> typically found in welding supply shops. These are known as a "pickling
> paste" which cleans high grade stainless of residue etc. "Antox" is a
> brand, versions of Antox 71E or Antox 73E is recommended. This is a
> hydroflouric acid and requires safe handling (don't get it in your eyes
> etc).
>
> I've also attached information on a citric based alternative which can be
> bought straight from the manufacturer. I hope this info isn't too late
for
> your service call!
>
> Kind regards
> Viessmann Manufacturing Company (U.S.) Inc.
> James F. McCarthy
> 45 Access Road
> 02886 Warwick RI
> phone: +1 401-732-0667 / fax: +1 401-732-0590
> e-mail: mcc@viessmann.com / web: www.viessmann-us.com

And the MSDS inforation he sent me...

STELLAR
v
SOLUTIONS
MATERIAL SAFETY DATA SHEET
05/20/04
SECTION I - PRODUCT AND COMPANY IDENTIFICATION
Supplier: Stellar Solutions, Inc. Manufacturer: Custom Formulating and Blending
4511 Prime Parkway 17716 Commerce Drive
McHenry, IL 60050 Bristol, IN 46507
(847) 854-2800
EMERGENCY TELEPHONE: (Chemtrec) (800) 424-9300
24 hours
Trade Name: CitriSurf 2310
Identification Number: STS-2310
Product Use/ Class: Specialty Cleaner
SECTION II - COMPOSITION/ INFORMATION ON INGREDIENTS
Item Chemical Name CAS NO. % By Wt.
less than
There are no hazardous ingredients in CitriSurf 2310
Citric Acid is "Generally Regarded as Safe", "GRAS", as a general food additive 21 CFR 184.1033
Exposure limits:
Item TLV/TWA TLV-STEL PEL-TWA PEL-CEILING TLV-TWA SKIN
(See Section 16 for abbreviation legend)
SECTION III - HAZARDS IDENTIFICATION
***EMERGENCY OVERVIEW***: Harmful if swallowed.
Effects of Overexposure - Eye Contact: Liquid, aerosols and vapors of this product are irritating and can cause
pain, tearing, reddening and swelling accompanied by a stinging sensation and/or a feeling like that of fine dust in
the eyes. May cause permanent eye damage if not treated immediately.
Effects of Overexposure - Skin Contact: Prolonged or repeated exposures can irritate or burn skin. Reaction may
be more severe if there is skin abrasion(s). Allergic sensitization in susceptible individuals is possible.
Effects of Overexposure - Inhalation: Prolonged inhalation may be harmful. May cause irritation to nose and
throat.
Effects of Overexposure - Ingestion: Irritating to mouth, throat and stomach. May cause discomfort, nausea,
vomiting, diarrhea if swallowed.

CitriSurf 2310 05/20/04 PAGE 2
SECTION III - HAZARDS IDENTIFICATION (continued)
Effects of Overexposure - Chronic Hazards: Repeated skin contact may cause a persistent irritation or
dermatitis.
Erosion of tooth enamel is possible from long-term overexposure.
Primary Routes of Entry: Skin Contact, Skin Absorption, Inhalation, Ingestion, Eye Contact
SECTION IV - FIRST AID MEASURES
First Aid - Eye Contact: IMMEDIATELY FLUSH EYES WITH WATER FOR 15 MINUTES. Get medical
attention immediately.
First Aid - Skin Contact: Wash with soap and water. Remove contaminated clothing. Get medical attention if
irritation develops or persists.
First Aid - Inhalation: Remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult,
give oxygen. Get immediate medical attention.
First Aid - Ingestion: If swallowed, do NOT induce vomiting. Give victim a glass of water. Call a physician or
poison control center immediately. Never give anything by mouth to an unconscious person.
SECTION V - FIRE AND EXPLOSION INFORMATION
Flash Point: N/A - Aqueous solution Flammable Limits: N/A
LEL: N/A
UEL: N/A
2 Extinguishing Media: None required - Aqueous solution. Alcohol, foam, CO , dry chemical, water fog may be
used.
Special Fire Fighting Procedures: If storage containers are involved in fire, keep cool with water spray to
prevent pressure build-up. As in any fire, wear self-contained breathing
apparatus pressure-demand (MSHA/NIOSH approved or equivalent) and
full protective gear.
Unusual Fire and Explosion Hazard: None known. "Empty" containers retain some product residue (liquid
and/or water vapor) and can be dangerous when pressurized. Empty drums
should be completely drained, properly bunged and promptly returned to a
drum reconditioner, or properly disposed of.
SECTION VI - ACCIDENTAL RELEASE MEASURES
Steps to be taken in case material is released or spilled: Absorb spill with inert material (e.g. dry sand or earth)
then place in a chemical waste container. Avoid runoff into storm sewers and ditches which lead to waterways.
Follow all government regulations.

CitriSurf 2310 05/20/04 PAGE 3
SECTION VII - HANDLING AND STORAGE
HANDLING: Wash thoroughly after handling. Do not get into eyes, on skin or on clothing.
STORAGE: Keep container closed when not in use. Store in corrosion resistant containers. Store away from
incompatible materials. Aqueous solutions of citric acid can, if in contact with reactive metals, (iron, zinc,
aluminum) form hydrogen- an extremely flammable gas.
SECTION VIII - EXPOSURE CONTROLS/ PERSONAL PROTECTION
Engineering Controls: Good general ventilation should be sufficient to control airborne levels. Facilities storing
or utilizing this material should be equipped with an eyewash facility and a safety shower.
Respiratory Protection: A respiratory protection program that meets OSHA 1910.134 and ANSI Z88.2
requirements must be followed whenever workplace condition warrant a respirator’s use.
Skin Protection: The glove(s) listed below may provide protection against permeation. Gloves of other chemically
resistant materials may not provide adequate protection. Polyvinyl chloride, Impervious gloves. Consult your
glove manufacturer for compatibilities.
Eye Protection: Wear chemical splash goggles. DO NOT WEAR CONTACT LENSES.
Other Protective Equipment: Wear suitable protective clothing to minimize and /or prevent contact. An eyewash
and safety shower should be present in the immediate area when handling this product.
Hygienic Practices: Wash hands before eating. Remove contaminated clothing and wash before reuse. Use only in
well ventilated area. Follow all MSDS/ label precautions even after containers are emptied because they may retain
product residues.
SECTION IX - PHYSICAL AND CHEMICAL PROPERTIES
Boiling Point: 212°F Melting Point: NA
Odor: N.D. Appearance: Clear, pale-colorless
Specific Gravity: 1.1 Solubility in Water: Complete
Vapor Density Heavier than air Vapor Pressure N.D.
Physical State: Heavy liquid Odor threshold: N.D.
Evaporation Rate: <1 Freeze Point: N.D.
(Butyl Acetate= 1) pH @ 100 % ~2
Viscosity: N.D. Coeff. of water/oil distribution: N.D.
See Section 16 for abbreviation legend
SECTION X - STABILITY AND REACTIVITY
Stability: Unstable_____ Stable X Conditions to Avoid: NA
Incompatibility: Strong bases, alkali metals, organic acids, oxides of sulfur, strong oxidizers, strong reducing
agents, caustic materials.
Hazardous Decomposition or byproducts: Carbon dioxide, carbon monoxide
Hazardous Polymerization: Will not occur under normal conditions.

CitriSurf 2310 05/20/04 PAGE 4
SECTION XI - TOXICOLOGICAL PROPERTIES
Threshold Limit Value: LD 50 (ORAL-RAT) 11.7 g/kg (as dry material)
LD 50 (SCU-RAT) 5500 mg/kg (as dry material)
LD 50 (IPR-RAT) 883 mg/kg (as dry material)
LD 50 (ORAL-MOUSE) 5040 mg/kg (as dry material)
Carcinogenicity: NTP? NA IARC Monographs? NA OSHA Regulated? NA
SECTION XII - ECOLOGICAL PROPERTIES
Ecological Information: No information.
SECTION XIII - DISPOSAL CONSIDERATIONS
Disposal Method: Follow all federal, state and local regulations.
SECTION XIV - TRANSPORTATION INFORMATION
DOT Proper Shipping Name: Compound, Rust Preventing, NOI
DOT Hazard Class: Not DOT Regulated (Class 55)
SECTION XV - REGULATORY INFORMATION
U. S. Federal Regulations as follows:
OSHA: Hazardous by definition of Hazard Communication Standard ( 29 CFR 1910.1200)
CERCLA - SARA Hazard Category: This product has been reviewed according to the EPA "Hazard Categories"
promulgated under Sections 311 and 312 of the Superfund Amendment and Reauthorization Act of 1986 (SARA
Title III) and is considered, under applicable definitions, to meet the following categories:
Immediate Health Hazard
SARA Section 313:
This product contains the following substances subject to the reporting requirements of Section 313 of Title III of
the Superfund Amendments and Reauthorization Act of 1986 and 40 CFR Part 372:
No SARA Section 313 components exist in this product.
TOXIC SUBSTANCES CONTROL ACT (TSCA):
The chemical substances in this product are on the TSCA Section 8 Inventory.
This product contains the following chemical substances subject to the reporting requirements of TSCA
12(B) if exported from the United States:
No information is available.

CitriSurf 2310 05/20/04 PAGE 5
SECTION XV - REGULATORY INFORMATION (Continued)
NEW JERSEY RIGHT-TO-KNOW:
No non-hazardous materials are among the top five ingredients.
PENNSYLVANIA RIGHT-TO-KNOW:
No non-hazardous ingredients are present in the product at greater than 3%.
CALIFORNIA PROPOSITION 65:
No Proposition 65 ingredients are present in the product.
INTERNATIONAL REGULATIONS: As follows -
Canadian WHMIS: This MSDS has been prepared in compliance with Controlled Product Regulations
except for use of the 16 headings.
Canadian WHMIS Class: No information available.
SECTION XVI - OTHER INFORMATION
HMIS RATINGS - Health: 1 Flammability: 0 Reactivity: 0
___________________________ 09/11/03 05/20/04
Signature of Preparer Date Prepared Date Revised
Reason for Revision: pH change Previous Revision Date:
Legend: N.A. - Not Applicable N.E. - Not Established N.D. - Not Determined
While the company believes that the data contained herein is factual and the opinions expressed are based on tests
and data believed to be reliable, it is the user’s responsibility to determine the safety, toxicity and suitability for his
own use of the product described herein. Since the actual use by others is beyond our control, no guarantee,
expressed or implied, is made by this company as to the effects of such use, the results to be obtained, or the safety
and toxicity of the product, nor does this company assume any liability arising out of the use, by others, of the
product referred to herein. Nor is the information herein to be construed as absolutely complete since additional
information may be necessary or desirable when particular or exceptional conditions or circumstances exist or
because of applicable laws or governmental regulations.

And the manufacturers use infomration...

STELLAR
v
SOLUTIONS
MATERIAL SAFETY DATA SHEET
05/20/04
SECTION I - PRODUCT AND COMPANY IDENTIFICATION
Supplier: Stellar Solutions, Inc. Manufacturer: Custom Formulating and Blending
4511 Prime Parkway 17716 Commerce Drive
McHenry, IL 60050 Bristol, IN 46507
(847) 854-2800
EMERGENCY TELEPHONE: (Chemtrec) (800) 424-9300
24 hours
Trade Name: CitriSurf 2310
Identification Number: STS-2310
Product Use/ Class: Specialty Cleaner
SECTION II - COMPOSITION/ INFORMATION ON INGREDIENTS
Item Chemical Name CAS NO. % By Wt.
less than
There are no hazardous ingredients in CitriSurf 2310
Citric Acid is "Generally Regarded as Safe", "GRAS", as a general food additive 21 CFR 184.1033
Exposure limits:
Item TLV/TWA TLV-STEL PEL-TWA PEL-CEILING TLV-TWA SKIN
(See Section 16 for abbreviation legend)
SECTION III - HAZARDS IDENTIFICATION
***EMERGENCY OVERVIEW***: Harmful if swallowed.
Effects of Overexposure - Eye Contact: Liquid, aerosols and vapors of this product are irritating and can cause
pain, tearing, reddening and swelling accompanied by a stinging sensation and/or a feeling like that of fine dust in
the eyes. May cause permanent eye damage if not treated immediately.
Effects of Overexposure - Skin Contact: Prolonged or repeated exposures can irritate or burn skin. Reaction may
be more severe if there is skin abrasion(s). Allergic sensitization in susceptible individuals is possible.
Effects of Overexposure - Inhalation: Prolonged inhalation may be harmful. May cause irritation to nose and
throat.
Effects of Overexposure - Ingestion: Irritating to mouth, throat and stomach. May cause discomfort, nausea,
vomiting, diarrhea if swallowed.

CitriSurf 2310 05/20/04 PAGE 2
SECTION III - HAZARDS IDENTIFICATION (continued)
Effects of Overexposure - Chronic Hazards: Repeated skin contact may cause a persistent irritation or
dermatitis.
Erosion of tooth enamel is possible from long-term overexposure.
Primary Routes of Entry: Skin Contact, Skin Absorption, Inhalation, Ingestion, Eye Contact
SECTION IV - FIRST AID MEASURES
First Aid - Eye Contact: IMMEDIATELY FLUSH EYES WITH WATER FOR 15 MINUTES. Get medical
attention immediately.
First Aid - Skin Contact: Wash with soap and water. Remove contaminated clothing. Get medical attention if
irritation develops or persists.
First Aid - Inhalation: Remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult,
give oxygen. Get immediate medical attention.
First Aid - Ingestion: If swallowed, do NOT induce vomiting. Give victim a glass of water. Call a physician or
poison control center immediately. Never give anything by mouth to an unconscious person.
SECTION V - FIRE AND EXPLOSION INFORMATION
Flash Point: N/A - Aqueous solution Flammable Limits: N/A
LEL: N/A
UEL: N/A
2 Extinguishing Media: None required - Aqueous solution. Alcohol, foam, CO , dry chemical, water fog may be
used.
Special Fire Fighting Procedures: If storage containers are involved in fire, keep cool with water spray to
prevent pressure build-up. As in any fire, wear self-contained breathing
apparatus pressure-demand (MSHA/NIOSH approved or equivalent) and
full protective gear.
Unusual Fire and Explosion Hazard: None known. "Empty" containers retain some product residue (liquid
and/or water vapor) and can be dangerous when pressurized. Empty drums
should be completely drained, properly bunged and promptly returned to a
drum reconditioner, or properly disposed of.
SECTION VI - ACCIDENTAL RELEASE MEASURES
Steps to be taken in case material is released or spilled: Absorb spill with inert material (e.g. dry sand or earth)
then place in a chemical waste container. Avoid runoff into storm sewers and ditches which lead to waterways.
Follow all government regulations.

CitriSurf 2310 05/20/04 PAGE 3
SECTION VII - HANDLING AND STORAGE
HANDLING: Wash thoroughly after handling. Do not get into eyes, on skin or on clothing.
STORAGE: Keep container closed when not in use. Store in corrosion resistant containers. Store away from
incompatible materials. Aqueous solutions of citric acid can, if in contact with reactive metals, (iron, zinc,
aluminum) form hydrogen- an extremely flammable gas.
SECTION VIII - EXPOSURE CONTROLS/ PERSONAL PROTECTION
Engineering Controls: Good general ventilation should be sufficient to control airborne levels. Facilities storing
or utilizing this material should be equipped with an eyewash facility and a safety shower.
Respiratory Protection: A respiratory protection program that meets OSHA 1910.134 and ANSI Z88.2
requirements must be followed whenever workplace condition warrant a respirator’s use.
Skin Protection: The glove(s) listed below may provide protection against permeation. Gloves of other chemically
resistant materials may not provide adequate protection. Polyvinyl chloride, Impervious gloves. Consult your
glove manufacturer for compatibilities.
Eye Protection: Wear chemical splash goggles. DO NOT WEAR CONTACT LENSES.
Other Protective Equipment: Wear suitable protective clothing to minimize and /or prevent contact. An eyewash
and safety shower should be present in the immediate area when handling this product.
Hygienic Practices: Wash hands before eating. Remove contaminated clothing and wash before reuse. Use only in
well ventilated area. Follow all MSDS/ label precautions even after containers are emptied because they may retain
product residues.
SECTION IX - PHYSICAL AND CHEMICAL PROPERTIES
Boiling Point: 212°F Melting Point: NA
Odor: N.D. Appearance: Clear, pale-colorless
Specific Gravity: 1.1 Solubility in Water: Complete
Vapor Density Heavier than air Vapor Pressure N.D.
Physical State: Heavy liquid Odor threshold: N.D.
Evaporation Rate: <1 Freeze Point: N.D.
(Butyl Acetate= 1) pH @ 100 % ~2
Viscosity: N.D. Coeff. of water/oil distribution: N.D.
See Section 16 for abbreviation legend
SECTION X - STABILITY AND REACTIVITY
Stability: Unstable_____ Stable X Conditions to Avoid: NA
Incompatibility: Strong bases, alkali metals, organic acids, oxides of sulfur, strong oxidizers, strong reducing
agents, caustic materials.
Hazardous Decomposition or byproducts: Carbon dioxide, carbon monoxide
Hazardous Polymerization: Will not occur under normal conditions.

CitriSurf 2310 05/20/04 PAGE 4
SECTION XI - TOXICOLOGICAL PROPERTIES
Threshold Limit Value: LD 50 (ORAL-RAT) 11.7 g/kg (as dry material)
LD 50 (SCU-RAT) 5500 mg/kg (as dry material)
LD 50 (IPR-RAT) 883 mg/kg (as dry material)
LD 50 (ORAL-MOUSE) 5040 mg/kg (as dry material)
Carcinogenicity: NTP? NA IARC Monographs? NA OSHA Regulated? NA
SECTION XII - ECOLOGICAL PROPERTIES
Ecological Information: No information.
SECTION XIII - DISPOSAL CONSIDERATIONS
Disposal Method: Follow all federal, state and local regulations.
SECTION XIV - TRANSPORTATION INFORMATION
DOT Proper Shipping Name: Compound, Rust Preventing, NOI
DOT Hazard Class: Not DOT Regulated (Class 55)
SECTION XV - REGULATORY INFORMATION
U. S. Federal Regulations as follows:
OSHA: Hazardous by definition of Hazard Communication Standard ( 29 CFR 1910.1200)
CERCLA - SARA Hazard Category: This product has been reviewed according to the EPA "Hazard Categories"
promulgated under Sections 311 and 312 of the Superfund Amendment and Reauthorization Act of 1986 (SARA
Title III) and is considered, under applicable definitions, to meet the following categories:
Immediate Health Hazard
SARA Section 313:
This product contains the following substances subject to the reporting requirements of Section 313 of Title III of
the Superfund Amendments and Reauthorization Act of 1986 and 40 CFR Part 372:
No SARA Section 313 components exist in this product.
TOXIC SUBSTANCES CONTROL ACT (TSCA):
The chemical substances in this product are on the TSCA Section 8 Inventory.
This product contains the following chemical substances subject to the reporting requirements of TSCA
12(B) if exported from the United States:
No information is available.

CitriSurf 2310 05/20/04 PAGE 5
SECTION XV - REGULATORY INFORMATION (Continued)
NEW JERSEY RIGHT-TO-KNOW:
No non-hazardous materials are among the top five ingredients.
PENNSYLVANIA RIGHT-TO-KNOW:
No non-hazardous ingredients are present in the product at greater than 3%.
CALIFORNIA PROPOSITION 65:
No Proposition 65 ingredients are present in the product.
INTERNATIONAL REGULATIONS: As follows -
Canadian WHMIS: This MSDS has been prepared in compliance with Controlled Product Regulations
except for use of the 16 headings.
Canadian WHMIS Class: No information available.
SECTION XVI - OTHER INFORMATION
HMIS RATINGS - Health: 1 Flammability: 0 Reactivity: 0
___________________________ 09/11/03 05/20/04
Signature of Preparer Date Prepared Date Revised
Reason for Revision: pH change Previous Revision Date:
Legend: N.A. - Not Applicable N.E. - Not Established N.D. - Not Determined
While the company believes that the data contained herein is factual and the opinions expressed are based on tests
and data believed to be reliable, it is the user’s responsibility to determine the safety, toxicity and suitability for his
own use of the product described herein. Since the actual use by others is beyond our control, no guarantee,
expressed or implied, is made by this company as to the effects of such use, the results to be obtained, or the safety
and toxicity of the product, nor does this company assume any liability arising out of the use, by others, of the
product referred to herein. Nor is the information herein to be construed as absolutely complete since additional
information may be necessary or desirable when particular or exceptional conditions or circumstances exist or
because of applicable laws or governmental regulations.

PS, This is obviously some serious chemicals. Don't scratch your nose with the stuff on your hands, or you may end up looking like Michael Jackson...

Be careful out there...

ME

Constantin

Agreed...

... though I suspect that the most likely cuplrit is not the HX material but either entrained contaminants in the combustion air or inside the gas.

I have a hard time believing that HX's with grades of SS as high as the Vitodens would decompose in any appreciable manner after just one year of use. Otherwise, the manufacturers of these HX's would be out of business a long time ago.

So my bet is that little things we do find in Munchkins and Vitodens' are remnants of things that got past the filters either at the intake or at the gas company. Considering how much combustion air goes over the HX, I'm surprised not to see more stuff in there. Areas that feature very dusty conditions would benefit from a filter on the intake, IMO.

Weezbo

Mike, from the oil side of the frozen north....

a viessman usually has ,if anything, a small condensate trail of white at the very front,that looks somewhat like a V about 2" at the top....natural gas boilers i have no idea.... however, it is suprising that the gas module has more signs of combustion than oil...maybe it is normal for condensing gas boilers.Ihad a thought that the particulates look like insects i wonder if these are the bone yards of unwary flies and roaches....maybe? i now have an idea what they look like after a year.Thanks.*~/:)

tim smith

heat x build up

Looks just like the munchie after a year, I too do not know what the mouse turds are but oh well.