50
10.4 Boiler Operation
Domestic hot water supply always takes priority over central
heating.
Demand for hot water required during central heating period,
boiler automatically switches to hot water mode until demand
is satisfied i.e. storage water is to required temperature.
This interruption in central heating is only when demand for
hot water is present and should not be noticed by the User.
10.5 Central Heating Mode
1.
Call for heat. Pump will start to circulate central heating
water, operating the flow switch.
2.
Fan will run. Once fan speed is reached burner will light.
3.
Burner output automatically adjusts to suit system
demand; as temperature of water in boiler approaches
that set by adjustable temperature selector, burner output
is reduced.
4.
When set temperature is reached, burner is turned off
and fan stops. Pump continues to run for three minutes
to remove residual heat build up in boiler. Burner will not
relight for 3 minutes.
5.
If CH sensor has not registered pre-set temperature but
room thermostat is satisfied the burner is turned off. Fan
stops. Pump continues to run for three minutes. In this
instance there is no 3 minute delay before burner relights.
6.
If there is demand for DHW during 3 minute burner delay,
boiler will operate to provide DHW until tap is closed.
Boiler will immediately revert to provide CH if there is
demand.
10.6 Domestic Hot Water Mode
• Flow switch senses demand for hot water (opening a hot
water tap, etc.), the pump starts and burner lights at its
ignition output, increasing to its maximum output.
• Water in the boiler is diverted from central heating
system to domestic hot water heat exchanger, heating the
incoming supply water.
• Burner output is varied to maintain temperature of hot
water as set by the adjustable temperature selector.
•
When flow switch senses hot water is no longer required
burner is turned off. Boiler immediately returns to central
heating mode.
10 - OPERATING INSTRUCTIONS
10.7 Frost Protection
Boiler has a built in frost thermostat which automatically turns
boiler and pump on.
If water in boiler falls below 41°F (5°C), providing the display
is switched on, boiler will operate until water temperature in
the system reaches approximately 86°F (30°C).
Frost protection is for the boiler only and not for complete
Central Heating System.
10.8 Pump
If display is switched on and boiler has not operated for 24
hours for heating or hot water, pump will operate automatically
for five minutes every 24 hours.
10.9 Low Water Pressure Sensor (Internal)
This device protects the primary exchanger from damage. It will
not allow the boiler to run in a LOW water pressure situation. Low
water condition occurs when water pressure drops below 7.0 psi
(0.5 bar), approximately.
240011941 REV B, [03/31/2018]
Summary of Contents for MAC-150
Page 2: ...MAC 205 ...
Page 4: ...MAH 165 ...
Page 65: ...61 APPENDIX A WIRING DIAGRAMS A 1 MODELS 125 Heat Only 240011941 REV B 03 31 2018 ...
Page 66: ...62 APPENDIX A WIRING DIAGRAMS A 2 MODELS 165 Heat Only 240011941 REV B 03 31 2018 ...
Page 67: ...63 APPENDIX A WIRING DIAGRAMS A 3 MODELS 150 Combi 240011941 REV B 03 31 2018 ...
Page 68: ...64 APPENDIX A WIRING DIAGRAMS A 4 MODELS 205 Combi 240011941 REV B 03 31 2018 ...
Page 69: ...65 NOTES 240011941 REV B 03 31 2018 ...
Page 70: ...66 NOTES 240011941 REV B 03 31 2018 ...
Page 81: ...9 125 WITH ZONE CIRCULATOR PUMPS 125 with Zone Circulator Pumps PN 240011430 REV G 03 31 18 ...
Page 84: ...12 125 WITH ZONE VALVES PIPING DIAGRAM 125 with Zone Valves PN 240011430 REV G 03 31 18 ...
Page 90: ...18 165 with Zone Valves 165 WITH ZONE VALVES PIPING DIAGRAM PN 240011430 REV G 03 31 18 ...
Page 94: ...22 150 205 WITH ZONE PUMPS WIRING DIAGRAM 150 205 With Zone Pumps PN 240011430 REV G 03 31 18 ...
Page 102: ...30 MODEL 125 Heat Only 125 HEAT ONLY WIRING DIAGRAM PN 240011430 REV G 03 31 18 ...
Page 103: ...31 MODEL 165 Heat Only 165 HEAT ONLY WIRING DIAGRAM PN 240011430 REV G 03 31 18 ...
Page 104: ...32 MODEL 150 Combi 150 COMBI WIRING DIAGRAM PN 240011430 REV G 03 31 18 ...
Page 105: ...33 MODEL 205 Combi 205 COMBI WIRING DIAGRAM PN 240011430 REV G 03 31 18 ...
Page 110: ...38 Low Water Cutoff Detail LOW WATER CUTOFF NO NO YES PN 240011430 REV G 03 31 18 ...
Page 111: ...39 NOTES PN 240011430 REV G 03 31 18 ...
Page 112: ......
Page 115: ......
