Combi Boiler


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Old 01-04-23, 05:01 PM
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Combi Boiler

I recently installed a Bosch Greenstar Combi 100p. I'm using it only to heat cast iron radiators, not for DHW. I hooked up my house thermostat to a Taco SR501-4 Switching Relay. The problem is that every time the thermostat calls for heat, the boiler throws a communication fault A8. Any suggestions would be appreaciated.
 
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Old 01-04-23, 06:02 PM
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This is looking for a multiple boiler operation. Check the manual and see how to change to a single boiler application.

 
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Old 01-10-23, 06:02 PM
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You were right. I double checked the Appliance Type 4e setting and it was no longer Central Heating Only, but had reverted to Combi Mode. I reprogrammed it and watched it save the value, but every time I exit Service Mode it reverts to Combi Mode. There must be something I have to change first to allow Operation in Central Heating. I suspect disabling something in DHW, but can't find anything promising. Do you have any suggestions?
 
 

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