If anyone can help with our problem I will be eternally grateful. Here we go....
Approx a year ago we extended our house and had a new Alpha CB50 boiler fitted to cope with the new rads etc. The hot and cold water piping was extended to serve the new rooms. The boiler is fairly high capacity. The brochure quotes a “never ending supply of hot water” and a flow rate of up to 18 litres a minute.
The main problem is when running a bath, the water runs very hot for approx 5 mins (we think until the reservoir is empty) then it cools down to luke warm and the flow rate reduces. The boiler should start up and keep the water hot. After a few minutes it goes hot again but the flow is still low.
We have had Alpha engineers in who say there is nothing wrong with the boiler (3 times). They say that there is a shower or mixer tap on the system where cold water is leaking back into the hot water. Our plumbers are sceptical but as the recommendation of Alpha have fitted a non return valve on the hot water output from the boiler – it hasn’t solved the problem.
The confusing thing is that the hot tap in the kitchen and the bathroom work fine. They will supply hot water constantly. I have tried excluding any mixer taps etc from the system by turning off the isolation valves. The only device I can’t do this with is the shower as the pipework is behind the tiles.
As the Alpha engineer insists it is the shower at fault, I sourced a new cartridge for it but the problem persists.
Another possible clues:
The boiler overflow (I think it’s the pressure relief valve) drips constantly (24/7)
When running the bath the radiators cool down
Hope I have included all relevant info. This has been driving us mad for months so any help greatly appreciated.
Approx a year ago we extended our house and had a new Alpha CB50 boiler fitted to cope with the new rads etc. The hot and cold water piping was extended to serve the new rooms. The boiler is fairly high capacity. The brochure quotes a “never ending supply of hot water” and a flow rate of up to 18 litres a minute.
The main problem is when running a bath, the water runs very hot for approx 5 mins (we think until the reservoir is empty) then it cools down to luke warm and the flow rate reduces. The boiler should start up and keep the water hot. After a few minutes it goes hot again but the flow is still low.
We have had Alpha engineers in who say there is nothing wrong with the boiler (3 times). They say that there is a shower or mixer tap on the system where cold water is leaking back into the hot water. Our plumbers are sceptical but as the recommendation of Alpha have fitted a non return valve on the hot water output from the boiler – it hasn’t solved the problem.
The confusing thing is that the hot tap in the kitchen and the bathroom work fine. They will supply hot water constantly. I have tried excluding any mixer taps etc from the system by turning off the isolation valves. The only device I can’t do this with is the shower as the pipework is behind the tiles.
As the Alpha engineer insists it is the shower at fault, I sourced a new cartridge for it but the problem persists.
Another possible clues:
The boiler overflow (I think it’s the pressure relief valve) drips constantly (24/7)
When running the bath the radiators cool down
Hope I have included all relevant info. This has been driving us mad for months so any help greatly appreciated.