POTTERTON COMMERCIAL PRODUCTS DIVISION
SECTION 1
INSTALLATION, OPERATION & MAINTENANCE MANUAL
NXR3
PAGE 3
1.
FUEL CONSUMPTION
Gas fuel consumption is based on natural gas with a gross calorific value of 38.6 MJ/m
3
. The gas rate
should be corrected for the meter supply pressure particularly on high pressure supplies to prevent
overfiring.
Fuel oil consumption is based on Class D (35 second) gas oil with a calorific value of 58.24 MJ/lit and a
density of 0.855 kg/lit, Kerosene (Class C2) has a calorific value of 53.22 MJ/lit and a density of 0.795
kg/lit.
2.
MINIMUM OPERATING PRESSURE
This is the minimum operating pressure of the boilers with pumps operating (NOT static pressure). The
requirements of the Health & Safety Executive guidance note PM5 regarding maximum operating
temperatures should be observed.
3.
BOILER FLUE CONNECTION
This is the nominal flue size of the flue connection spigot, for dimensional details of the flue connection
spigot see Fig. 1. Actual flue size required to achieve correct draught and operation under all running
conditions may need to be increased.
4.
FLUE GAS VOLUME
Flue gas volumes are given at STP (standard temperature and pressure [15
°
C and 1013.25 mbar]).
Typical flue gas temperatures are given in Table 2.
5.
NATURAL VENTILATION
The sizes indicated are free grille areas and are based on a single boiler installation.
6.
MECHANICAL VENTILATION
The volume given is for a single boiler installation.
7.
CONNECTION SIZES
The boiler water connections are 2 ½” BSP screwed flange PN6. Also supplied 2 ½” welded flanges.
8.
WATER FLOW RATES
Water flow rates are given for boiler flow and return water temperature differences of 11
°
C.
9.
COLD FEED/ OPEN VENT/ SAFETY VALVE SIZES
Sizes indicated are minimum sizes for single boiler installations.
10.
MINIMUM RETURN TEMPERATURE
If system return temperatures below 55
°
C are required the contact the Potterton Commercial Technical
Department.
11.
WEIGHT
The dry weight is exclusive of the burner and gas train. Each section measures approximately 1100mm
(high)
×
606mm (wide)
×
180mm (deep) and weighs 106kg (inter), 110kg (front), 125kg (rear).
ANY PERSON OR PERSONS MOVING OR LIFTING SHOULD BE TRAINED IN MANUAL HANDLING
TECHNIQUES AND IF NECESSARY USE SUITABLE LIFTING EQUIPMENT TO REDUCE THE RISK OF
INJURY TO THEMSELVES OR OTHER PEOPLE.
12. Some burners may require higher than 17.0 mbar inlet pressure, please see relevant burner card for details,
or contact the Commercial Technical Office.