one of those wks glowworm betacom a

[buckley plumb]

fitted a betacom 28a about 5 months ago and got called back to it today due to poor ho****er - checked at taps only 39degrees with tap on full flow or low flow . water temp set at 60 - 14 degres across plate - flow 73 rtn 56 on boiler . checked fan target and actual values which were ok . inlet pressure 20mb on full . only thing i could see was the burner seemed to hunt up and down . called glowworm out under warranty they are coming tomorrow . asked customer to get engineer to write down what fault was . i was thinking thermistor due to only 73 on flow or fan

 

[buckley plumb]

engineer rang me to let me know the problem - was the shower mixer valve letting cold into the hot causing the boiler to fluctuate burner all over the place .he turned the cold supply to the boiler off and turned the hot tap on - there would be a pulsed flow as mentioned from the shower mixer. you learn something new every day