Glow worm Ultracom 30 cxi query

[Waigo1]

Hi all

Homeowner with little understanding of boilers...

Heating is working fine and hot water is working fine from the bathroom basin taps. Pressure is at 1.6. The issue is that from the bathroom bath taps and kitchen taps (which appear to be higher pressure), hot water runs for a bit but then runs cold. I’ve checked what happens on the boiler display when the water goes cold and the ’burner‘ flames display on the right hand side drop from 5 out of 5 flames lit down to 1 out of 5 flames lit. This doesn’t happen when I use the bathroom basin taps, which stay with flames lit on the display and continues to provide hot water.

Any ideas?!

Thanks

Craig

 

[green grant]

pressure has nothing to do with tap output (central heating only)
You have a combi so all water comes from a single pipe to all other hot water outlets so "higher pressure" you describe is an example of "less resistance" in the pipe run as the pressure leaving the combi is always the same.
The good news is that you don't need anything expensive or major replaced as it heats DHW and CH.
Before calling a "heating engineer" you can do some tests yourself. Get a bucket and timer on your phone and run the hot water taps in turn for 30 seconds and then with a kitchen measuring jug, see what came out in 30 seconds then double to get your flow in L/min. Compare the findings between the taps, see what the data sheets says about flow rate then try and discover why the difference.(isolation valves not fully open, that sort of thing)
My initial thought is the resistance on the thermistor for DHW is at the edge of tolerance and will need replaced. Thermistors should be a service part, swapped annually. The pressure regulator switch is far less sensitive which is why I have excluded it as a primary indicator.