DAVIS Shelter Heaters User Manual

EATER

H

FOR C

OR MULTI-PURPOSE SHELTER

The heater may be used with the Complete System Shelter (CSS) or the Multi­Purpose Shelter (MPS). Used with either shelter, it will protect the contents of
the shelter from damage due to cold weather or condensation. Use the heater if
you expect temperatures below 0˚F (-18˚C) or condensation.

Please note that we have made every attempt to design and manufacture a safe
product, but Davis Instruments assumes no liability for any injury or damage
caused directly or indirectly by the installation or use of this product.

CAUTION:

Although the nominal heater voltage is not hazardous, a short in the wall transformer
could cause hazardous voltage to appear on the heater wires. For safety, you should
always turn the heater’s power unit to the “OFF” position before opening the shelter.
We also recommend that you unplug the wall transformer before opening the shelter.

OMPLETE SYSTEM SHELTER

Product #7726, 7730

OMPONENTS

C

The heater includes components pictured below as well as the insulation blan­kets pictured on the following page. Please make sure you have all listed com­ponents before continuing.

OMPONENTS

C

Page 2 Heater

Insulation Blankets

Included in your heater package will be the insulation blankets appropriate for
either the Complete System Shelter or the Multi-Purpose Shelter, as pictured
below.

CSS H

EATER INSULATION BLANKETS

MPS H

EATER INSULATION BLANKETS

T

OOLS

AND

M

ATERIALS

In addition to the components listed above, you will need some of the follow­ing tools and materials. Please be sure you have everything you need before
beginning the installation.

Medium Phillips Screwdriver

✦

Wire Cutter

✦
✦

Wire Stripper or Knife
Cable Clips or Weather-Resistant Cable Ties

✦

Tools and Materials Needed for Installation Page 3

N

EEDED

FOR

I

NSTALLATION

)

Choosing Cable for the Heater

The heater comes with a 50-foot (15 m) length of 22 gauge, two twisted-pair
cable. When using this cable, the red and white wires are joined and used as
one wire and the two black wires are joined and used as one wire. You may use
22 gauge, two-twisted pair wire in this manner for cable lengths up to 120 feet
(36 m). If you want to use single pair cable, use the following table to deter­mine the minimum wire size for the desired length of cable run.

ENGTH

OF

ABLE

L

C

R

UN

Up to 60 feet (18 m) 22AWG (0.50 mm
60-100 feet (18-30 m) 20AWG (0.75 mm
100-160 feet (30-50 m) 18AWG (1.0 mm
160-250 feet (50-80 m) 16AWG (1.50 mm

INIMUM

M

W

IRE

2

)

IZE

S

2

)

2

)

2

If the heater cable is routed with a system signal cable, be aware that for cable
runs over 50 feet (15 m), you need to do at least one of the following to prevent
the heater cable’s voltage from interfering with sensor voltages.

✦

Use twisted pair for the heater cable or the signal cable.
Use shielded cable for the heater cable or signal cable (shield must be

✦

grounded).

✦

Keep the heater cable and the signal cable separated by several inches (at
least 8 cm) over most of the length of the cable run.

Page 4 Heater