Central Heating Question

Combi boiler heating water red hot for first few minutes

Hi all, am after advice on my Baxi Duo-tec Combi GA 40kW boiler which has been installed for less than a year.
I have the water temperature set at 42 but when I turn on hot water tap the water runs extremely hot for 2-3 mins going up to 60c on the digital screen until it settles down to 42c and then remains steady.
I've had the heating engineers out twice. First time because the temperature of the water was all over the place whilst running. This was fixed but had them out again because of the extremely hot water on start up.
The engineer said that its not a problem and its a powerful boiler for the size of my property ( 3 bedroom semi with 2 people in) I thought from the offset that it was a powerful boiler but went along with the guy who fitted it.
Any advice appreciated

2 Answers

Without the benefit of seeing the property to carry out a heat loss calculation which your installer should have done before selecting the appropriate size of boiler, I can only speculate that the boiler does seem a little bit over sized.

You state the DHW rises when you initially call for hot water but then drops to a more comfortable temperature after several minutes, this clearly is not delivering water a the required pre-set temp. Suggest because the boiler is less than 1 year old and still covered by the manufacturer's warranty, you call them and request a technician attend to rectify this fault.

The boiler should have a Domestic Hot Water NTC Sensor fitted, this maintains the temp you have set it at the control panel and should deliver that desired temp until you adjust it. Soon as you turn a DHW tap/outlet on the burner will light automatically and the temperature of the domestic hot water is controlled by the above sensor.

Answered 22nd Sep 2013

Boiler Homecare

Member since 6 Jan 2010

We used to find that the silicone tube off the gas valves was always too long which stops the boiler from modulating and always got trapped when the front fascia was refitted. When it fires up it goes straight to high flame and stops there?

Answered 9th Feb 2014

Paul Caton Gas Services

Member since 23 Mar 2010

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