I’ve never been too happy with the condensing Vaillant EcoMax Pro 28E that replaced our original cast iron boiler heating our vented microbore system. The house didn’t seem to get any warmer than before the changeover about 5 years ago, but I’ve been told everything was OK so I did nothing about it.
When sorting paperwork out I found some information produced when the system was checked out to get the right boiler output. It indicates the rads and pipework create a 2.5m head pressure loss.
Looking at the boiler information online I see the boiler has a 2.5m head pressure loss while the original had almost none. The 28E spec says it needs a minimum flow of nearly 1400 litres/hour for the maximum output of 28kW with a flow/return differential fixed at 20C. The flow is set to 80C.
The installer didn’t change the pump, which was presumably selected to suit the original system of 8 rads off one 22mm manifold upstairs with the same setup downstairs.
Could the low heat be due to lack of pump head as the current one can’t move that much water through the pipes even at top speed.
Standard 5 or 6m head pumps can’t achieve the minimum flow at a 5m head either. However there is an 8m head one that can pump 1400 l/h at a 5m head but it’s for a 25mm internal pipe not 20mm.
Am I tackling this problem the right way?
When sorting paperwork out I found some information produced when the system was checked out to get the right boiler output. It indicates the rads and pipework create a 2.5m head pressure loss.
Looking at the boiler information online I see the boiler has a 2.5m head pressure loss while the original had almost none. The 28E spec says it needs a minimum flow of nearly 1400 litres/hour for the maximum output of 28kW with a flow/return differential fixed at 20C. The flow is set to 80C.
The installer didn’t change the pump, which was presumably selected to suit the original system of 8 rads off one 22mm manifold upstairs with the same setup downstairs.
Could the low heat be due to lack of pump head as the current one can’t move that much water through the pipes even at top speed.
Standard 5 or 6m head pumps can’t achieve the minimum flow at a 5m head either. However there is an 8m head one that can pump 1400 l/h at a 5m head but it’s for a 25mm internal pipe not 20mm.
Am I tackling this problem the right way?