plex,
The instructions for the DFARS ARE confusing. However, I do think that Davis gave you some bad information. The naturally aspirated VP2 has 5 shield plates which the instructions say to modify (remove the insulating disk) then rearrange position, then ADD a 6th "open plate". This can be deciphered in the section, "Assemble the Lower Section" of the installation manual (page 6 in mine). FWIW, I have 3 VP2 DEFARs and all are assembled with 6 lower plates. I have 1 VP2 with 24hr FARS and it has 7 lower plates. So, to summarize, 5 rings for naturally aspirated, 6 rings for DFARS, and 7 rings for 24 hr FARS.
Hello George
I did like illustration on page 8 in my manual:
http://www.davisnet.com/product_documents/weather/manuals/07395-236_IM_07747.pdf What I have left, is the old closed ring, with the isolation disc.
I can't see where I could add this, since another closed plate doesn't make any difference. And my bolts are not long enough to cary one more ring.
Mine looks like the first picture in my first post - 5 rings under the fan ring.
Totally confusion here
Here's what Davis technical support told me:
Dear Sir,
The radiation shield (6 rings) is for our 24 HOUR FAN.
24-HOUR
FAN-ASPIRATED
RADIATION SHIELD
Models with 24-hour
fan-aspirated radiation
shields include
additional radiation
shield plates and a
second solar panel,
which powers the
motor-driven fan.
The additional plate is where the Batteries (2, C Cell NiCad), and electronics for recharging the batteries are located, for night time use.
The radiation shield (5 Rings) is our DAYTIME FAN,
Daytime Fan-Aspirated Radiation
Shield Kit
An economical solution for adding the benefits
of fan aspiration by retrofitting your wireless or
cabled Vantage Pro2 or Pro2 Plus. Less costly
than our 24-hour fan-aspirated radiation shield,
but nearly 75% as effective in reducing the effects
of daytime radiation. With no backup battery, the
fan only runs during daylight hours and will cease
running at night when solar radiation effects are
reduced. Retrofit kit for Vantage Pro2 and Vantage
Pro2 Plus includes fan, solar panel, additional
radiation shield plates and hardware.
7747 Daytime Fan-Aspirated Radiation