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Aardvark Newsletter


Inside this issue:                                                      

  • Why does my furnace smell when I turn it on?
  • NADCA guidelines for coil cleaning
  • Type 1 and Type 2

Mechanical Cleaning Methodology:

The HVAC system must be cleaned using mechanical

Cleaning methods designed to dislodge and extract

contaminants from within the HVAC system

components. Mechanical cleaning techniques employ

sizeable vacuum collection units, portable vacuum

collection units, mechanical agitation systems, hand

brushing tools, pressurized air sources, pressurized

water sources, plus other tools and equipment to

dislodge attached particulate and debris and convey it to

a collection device in a safe and controlled manner.

Coil Surface Cleaning:

It is Highly Recommended that all portions of each coil

assembly be cleaned. Both upstream and downstream

sides of each coil section must be accessed for cleaning.

Where limited access is provided between close

proximity or zero-tolerance heating coils in an AHU,

cleaning may require removal and/or replacement.

Coil Inspection and Cleaning Process:

For the purposes of this standard a coil is defined as an

evaporator, chilled water, hydronic, steam, hot gas or

heat pipe which is located within the air stream of an

HVAC system for the purposes of indoor environmental


The process begins with an inspection. The substances

deposited on the coil help determine the initial selection

of the cleaning protocol. There are two (2) categories of

coil cleaning. Coil reconditioning will utilize Type1 or

Type-2 cleaning methods. Both Types require usage of

HEPA filtered negative air machines when exhausting

within an occupied space. HEPA filters are

recommended, but not required, when machines are

exhausted outside of building.

Negative air machines must be operated continuously

during the complete coil reconditioning process. The coil

must be physically isolated from the duct system during

the cleaning process to ensure disrupted particulate

does not migrate to or redeposit on unintended areas.

Type 1 Coil Cleaning:

Type 1 methods of coil cleaning are appropriate for

removing loose dust, dirt or debris collected upon

evaporator coil surfaces. Physical removal of debris is

accomplished through a variety of methods which may


HEPA filtered contact vacuuming the coil surfaces

with a vacuum capable of generating a minimum of –

40 inches water lift. HEPA filtered contact

vacuuming must be used in conjunction with the

evaporator coil being maintained with a negative

pressure differential to the general work


Contact vacuuming may require the use of crevice

tools and brushes.

Brushes may be used for penetrating between coil

fins and up to the first row of refrigerant tubes

without damaging the fins.

Compressed air accelerator guns and wands may

be used to dislodge debris embedded between the

evaporator coil fins without damaging the fins.

Evaporator fin combs and fin straightening tools

designed to restore the evaporator coil fins after

initial cleaning



Type 2 Coil Cleaning:

Type 2 cleaning methods are appropriate for removing

adhered debris on all coil, drain pan and drain line

surfaces. Type 2 cleaning should be performed after

non-adhered particulate has been removed using Type 1

methods. Type 2 cleaning may include the following


All methods under Type 1

It is not always possible to remove all motors and

electrical equipment from the coil area. However, it

is always possible to either remove, isolate and/or

protect electrical equipment.

Application of coil cleaning products. (Must be used

in accordance with the manufacturer’s product


Usage of electric chemical coil cleaner application


Usage of water washing at normal water line


Remediation of Mold and Other Biological


This section defines processes for remediating mold and

other biological contamination within an HVAC system.

It is highly recommended the remediation plan for mold

decontamination include removal of contaminated

materials or employ aggressive cleaning techniques

when removal is impractical. Removal of contaminated

porous HVAC system materials is recommended (See

ACGIH Bioaerosols: Assessment and Control, 1999).

8.1 Cleaning Methods

Surface cleaning must be performed using mechanical

agitation methods to remove particulate, debris, nutrient

sources and surface contamination. Mechanically

cleaned surfaces must be capable of passing

cleanliness verification methods as defined in this

standard (See Section 13).

8.2 Removal of Mold Contaminated Porous


It is highly recommended that porous materials with

actual fungal growth (Condition 3) be removed. The

exposed non-porous substrate underneath the porous

materials must be mechanically cleaned and treated

before new replacement material is installed.

When removal of all Condition 3 contaminated porous

material cannot be performed, partial removal to the

greatest extent possible should take place. This must be

followed by surface cleaning of remaining material using

mechanical cleaning methods.

Hope everyone has a safe and wonderful week! Check out our website for our weekly specials. We also run our specials on our Facebook page. Thanks again everyone and don’t forget to get your chimney inspected BEFORE you burn!


Aardvark Residential and Commercial Services Inc.








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Aardvark Residential and Commercial Services | 13015 6th St | Grandview, MO 64030 | (816) 945-6070