Installation guide
C:\Documents and Settings\Matt\My Documents\Business\everlast\content\commerical_315C250_MANUALandWarranty.doc Page 7 of 12 January, 2006 Revision 3 
COMBO System Capability 
The following chart will assist in the selection of the COMBO 
System that meets with your specific requirements. 
Even if you have specified a basic COMBO System with a single 
Bosch Continuous Flow Water Heater and the Everlast Accumulator 
and then your hot water delivery requirements increase; or if the hot 
water demand is not immediately known; this is a System where, if 
required, a further Bosch Continuous Flow Water Heater may be 
added. 
HOT WATER DELIVERY CHART 
COMBO with Bosch 17E, 21E or 25E Gas Heater Units & one 
Everlast 250 Litre C2 
Figures based on heating from 15 °C up to 65 °C (fairly typical) 
COMBO 
Unit Model 
Heat up 
Time 
(mins) 
Burner Size 
(MJ / hour) 
Tank 
Capacity 
(Litres) 
First hour 
delivery 
(Litres) 
Further hourly 
delivery 
(Litres/hr) 
250117E 36  132  250  784  534 
250121E 29  160  250  898  648 
250125E 24  200  250  1060  810 
** Notes for tables: Motel rooms will be a mixture of 1 bedrooms 
with 1 or 2 people showering (business accom. is typically 1 person); 
and 2 bedrooms with 2 or 3 persons showering. Therefore to average 
at 2 persons per room is conservative, safe design. 
These are scenarios ranging from small motel/hotel/unit 
developments up to significant multi room accommodation; serviced 
with very efficient hot water plant . 
3 Star Accommodation equals 30 Litres per person per Peak Hour 
5 Star Accommodation equals 45 Litres per person per Peak Hour
COMBO with Bosch 17E, 21E or 25E Gas Heater Units & one 
Everlast 315 Litre C2 
Figures based on heating from 15 °C up to 65 °C 
(fairly typical) 
COMBO 
Unit Model 
Heat up 
Time 
(mins) 
First hour 
delivery 
(Litres) 
Further 
hourly 
delivery 
(Litres/hr) 
Typical Number of 
motel/hotel rooms assuming 
2 persons per room 
showering. ** 
3 STAR 
ACCOM. 
5 STAR 
ACCOM 
315117E 36  849  534  14  9 
315121E 29  963  648  16  11 
315125E 24 1125  810  19  13 
[ Reference: Robert Bosch (Australia) Pty Ltd ] 
COMBO Pipe and Fittings Sizing Guidelines 
The Bosch-Everlast™COMBO Gas Hot Water System relies on the 
Everlast Accumulator which will accommodate from one to 5 Bosch 
Continuous Flow Water Heaters. 
Specified in conjunction with the Grundfos UPS 32-80 B pump, a 
system may be assembled with consistent pipe and fittings sizing. 
The 50 mm sizing of Primary Circulation piping in the COMBO 
design, ensures that the system will meet the range of major 
commercial applications of single or multiple Gas units; manifolded to 
the COMBO. Connection may be made using 50 mm direct coupling 
as required. The factors to be considered by the Installer are the 
mains supply piping/flow rates, and Secondary Circuit piping, if 
required. 
The following design principles should be considered in the 
determination of the mains and secondary piping sizes : 
If pipework is undersized for the required flow (litres/sec) or 
(litres/min), then the velocity will increase (metres/sec) resulting in an 
increased pressure loss. If pipework is oversized for the required 
flow, then the heat loss will be increased. 










