Page 39 - Dometic RM Series Refrigerators Service Manual
P. 39
20. PRESSURE DEVICES
The pressure at the burner should be checked at the time the refrigerator is started
up, After connecting the pressure gauge, set the thermostat dial at Turn on
the gas at the union cock and light burner. At the setting the pressure
reading should be (280 mm). The L.P. gas is supplied directly to the thermostat
from the regulator fitted on the gas bottle at pressure of 11” (280
Water U gauge (fig, 67)
The water gauge consists of a glass tube filled to with water.
pressure is exerted on one side of the gauge, the water on side is forced down
and there is a corresponding rise of water on the other side.
Water column pressure per square inch is indicated the difference of the two
columns of water measured in inches.
A convenient scale reading in inches and tenths of an inch is bctveen the
two columns.
When reading the gauge proceed as follows
If the gauge is filled with water to zero and the lower column is 5.5 inches
(140 below zero, the other column will also be 5.5 inches (140 By adding
the tvo together 5.5 + 5.5 11 inches (280 mm) water column,
For accuracy of measurement a vater gauge is far superior to a low pressure gauge.
If a low pressure gauge is used, it should be checked for accuracy against a water
gauge occasionally .
LOW PRESSURE GAUGE
Adopter
Part No.
.
WATER U I F - - 33 87
GAUGE
Fig.
Low pressure gauge (Fischer) (fig, 64)
This gauge is calibrated to read in “inches of water column pressure”. It is a
standard manometer reading and is colored red.
How to use the pressure gauge
When testing the pressure at the burner, remove the plug indicated with an arrow in
fig. 67 and fit the hose from the pressure gauge. Use adapter, part 33 87
It is very important that the gas operated refrigerators operate at correct pressure
i . e . at the pressure stipulated for the refrigerator.
21. OPERATING
Experience over many years shows that incorrect installation and adjustments are
major causes for unsatisfactory refrigeration.
