In September I had to replace our CH pump. I fitted a Grundfos UPS3 15-5065 130. The pump is working o.k. When we put the CH on, we started to get a waterhammer bang which we have not had since we live in this house, which has been 21 years. But I am not 100% certain whether the waterhammer started after replacing the pump because the CH was only on occasionally then.
The bang usually happens when the system shuts down the Central Heating. There is no bang when either CH or HW run on their own.
I have bled the system, i.e. radiators and hot water. There was a little bit of air in the odd radiator, but no more than any time before.
The pump is running on setting 1. I have tried the other settings too.
The mid position valve is a Honeywell V4073A1039 which has been in the house for a long time. Nothing else apart from the CH pump has been changed or fixed recently.
Does anyone have an idea how we can get rid of the bang easily? Or does the 3-port valve have to be replaced?
The bang usually happens when the system shuts down the Central Heating. There is no bang when either CH or HW run on their own.
I have bled the system, i.e. radiators and hot water. There was a little bit of air in the odd radiator, but no more than any time before.
The pump is running on setting 1. I have tried the other settings too.
The mid position valve is a Honeywell V4073A1039 which has been in the house for a long time. Nothing else apart from the CH pump has been changed or fixed recently.
Does anyone have an idea how we can get rid of the bang easily? Or does the 3-port valve have to be replaced?