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Very hot, hot and freezing cold water
Anonymous user 23/02/2024 - 3.08 PM
I have a Vaillant combi boiler. The heating works fine but the hot water temperature keeps fluctuating from very hot to warm and freezing cold. An engineer has cleaned out the small rectangular dish like heat exchanger and replaced the switching valve, outlet valve and the pump at a considerable cost to me but still the water temperature continues to fluctuate. Can anyone tell me what the real problem is so that I do not have to go through much further expenses. Thank you kindly.
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2 Answers
Anonymous user
sounds like you need a new plate heat exchanger cleaning the old one does not always gurantee success also divertor valve has that been checked?
Answered27 March 2017
0
Martin O'Toole Small jobs Handyman, Electrician, Builder
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Combi boilers can sometimes have head scratching problems, quite common is the fan running slow due to lack of lube on its shaft and the vacuum switch cutting in and out , bringing the boiler on off whilst drawing hot water, a squirt of wd 40 on the fan shaft can improve. Vacuum tubes from the fan to pressure switch can have cracks and leak air having the same effect.occasionally the stop tap may have been turned off and on and be giving too much flow and reducing the hot water temp. Getting a little more complicated, a dicky diverter valve can prevent full boiler output from going to hot tap water side and dicky flow switch or pressure switch on hot water sensing can create fault. A knowledgable engineer with test instruments should be able to sort.
Answered27 March 2017
0