I am sizing the central heating pipes for a complete replacement. The property has an elongated floor plan so I have used a piping layout consisting of single flow and return headers running the length of the property and take-offs to and from radiators.
Currently there is a combi boiler serving the property, which will be staying for now. But the idea is to size the pipes for a delta T (flow - return) of 5C for a possible future heat pump. One potential issue is with the central headers. If I use 28mm pipe, the pressure drop is something like 1m of pump head per 4m of pipe length. If the water circulation pumps in a heat pump are similar to the ones in combi boilers, this will be a problem. Is it normal for the central heating water circulation pumps in a heat pump to have higher head than those in a combi?
Currently there is a combi boiler serving the property, which will be staying for now. But the idea is to size the pipes for a delta T (flow - return) of 5C for a possible future heat pump. One potential issue is with the central headers. If I use 28mm pipe, the pressure drop is something like 1m of pump head per 4m of pipe length. If the water circulation pumps in a heat pump are similar to the ones in combi boilers, this will be a problem. Is it normal for the central heating water circulation pumps in a heat pump to have higher head than those in a combi?
