Heatslave 12/14 HW / hot water loses heat after 5 miniutes

[mike]

Hello i Just recently got my heatslave 12/14 working after 3 diverter valve replacements and 1 burner blower, it all works fine now but with one problem
when i use the ho****er to run a bath the water will run hot for about 5 miniutes and then it will cool down to lukewarm, i am guessing it is when the tank in the boiler empties but i have no idea realy; what could it be i have checked the thermostats and they dont make a bit of difference.

 

[kimbo]

It would be best to get an engineer out on this one. The diverter valve defaults to hot water, when you turn the hot tap on the flow switch detects a demand and sends a live signal to the pump and burner (via the hot water store stat). If the stat is satisfied the pump will pump the water out of the store and around the heat exchanger which gives its heat up to the cold water coming in from the hot side. I believe that this goes via a relay on the pcb which there is a bout 4 or 5. so as you can see it is not a straight forward job. An electrical tester will be required to see if the stat is calling and to check out the other components such as the flow switch etc.

 

[DirksPlumbing]

Hello i Just recently got my heatslave 12/14 working after 3 diverter valve replacements and 1 burner blower, it all works fine now but with one problem
when i use the ho****er to run a bath the water will run hot for about 5 miniutes and then it will cool down to lukewarm, i am guessing it is when the tank in the boiler empties but i have no idea realy; what could it be i have checked the thermostats and they dont make a bit of difference.

I am afraid your first suspicion is right. You could up the boiler output by fitting the biggest possible nozzle. But it is a general problem of having less than half of the required heat output available for continuous hot water flow.
Who advised you to choose this boiler?
For filling your bath you will need to run your hot water very slowly. Get yourself a flow cup. Then check your MI for the flow rate available and set your bath to roughly this flow rate and it will fill fine just it will take a while.

 

[kimbo]

When there is a demand for hot water does the burner fire up.

 

[mike]

Yes the boiler does fire as soon as the tap runs and you can hear the diverted valve going back in to home position , which for me is HW may I also add the pressure is 0.5 bar and the taps run very slow

 

[DirksPlumbing]

Have your boiler checked if the bigger available nozzle is fitted. Get your pressure up to 1.5 bar and believe it that after the exhaustion of the storage there is only water produced on the go which means somewhere in the range of 6l/min.

If you come back and tell me that you have been able to beat physics then you should get that patented as this would be the next thing to have, an oil boiler with 15kW input and above 30kW output would definitely be selling as sliced bread.