Overview
Process air filter, 20" × 20" × 2", MERV 8. Phoenix part number 4022636.
This is the filter on the process air stream — the air the machine dries and returns to the structure.
What it fits
- Phoenix D850 Desiccant — named in the manual as Process Air Filter Replacement 4022636, 20" × 20" × 2" MERV 8 Filter (Standard), and in the parts list as item 20, Air Filter, Process, one fitted
- Phoenix 300 LGR — two required (CCW record)
Process air and reactivation air are different filters
A desiccant dehumidifier runs two separate air streams, and each has its own filter. Getting them mixed up is the most common ordering mistake on these machines:
- Process air — the air being dried and returned to the structure. Filter 4022636, 20" × 20" × 2" MERV 8. This part.
- Reactivation air — the air heated to drive moisture off the desiccant wheel and exhaust it. Filter 4027168, 9" × 11-3/8" × 1/4".
Both need changing. Neither substitutes for the other.
Why it matters on a desiccant machine
The desiccant wheel is the expensive component in a D850, and the process filter is what stands between the wheel and everything the job is throwing into the air.
A loaded process filter costs airflow, and reduced process airflow reduces the machine's grain depression capacity directly. Worse, a filter that has collapsed or been left out lets fine particulate reach the wheel, where it blinds the desiccant media — and that is not a service item, it is rotor assembly 4036125 and seal kit 4036124.
On desiccant work the filter is genuinely protecting the asset.
When to change it
Change it between jobs on anything dusty, and check it whenever you move the machine. Desiccant machines are most often deployed on the difficult end of drying work — cold conditions, contained chambers, dense materials — which is exactly the work that loads filters fastest.
Do not wash a pleated media filter. Replace it.
Frequently asked questions
How many does my machine take?
One on the D850, two on the 300 LGR.
Is it the same as the reactivation filter?
No. That is 4027168 and it is a completely different size.
Can I run without it?
No. You risk blinding the desiccant wheel, which is the most expensive component in the machine.
What is MERV 8?
The media efficiency rating. MERV 8 is the standard specification Phoenix fit to this machine.
Running a D850? Order both filters together — the process filter and the reactivation filter are separate parts and both need changing.
