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Plumberpro, Home Appliance Technician
Category: Appliance
Satisfied Customers: 634
Experience:  Heating and hot water heating appliances experienced
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Quite suddenly my Vaillant boiler has become slow at delivering

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Quite suddenly my Vaillant boiler has become slow at delivering domestic hot water. It seems to have two or three goes before it finaly ignites. It is a Turbomax VUW 242 E and is around 12 years old. It was serviced in May this year by British Gas as part of my homecare agreement which I have now cancelled due to a 33% rise in their prices I have had a plumber (friend) to look at it and he has suggested I get in touch with Vaillant to sort out a plan. Theire helpline is closed until Monday. He tells me that the diverter valve and microswitch are working fine, as is the fan and temp cut - out. However, he did explain about the 2 thyristors and that the domestic one might be faulty. What do you think ?
Plumberpro : Hi , if it's trying to light then it can be one of three things, the fan is packing up ,the air pressure switch is faulty or if you can hear it trying to light then the flame rectification sensor is faulty . I would recommend getting a good heating engineer recommended by freind
Plumberpro : s , family , neighbours etc,. Someone they have used more than once . Not British Gas , they aren't great . Good luck . Please don't forget to rate.
Plumberpro : Hi . Try the heating as well . Does it do the same thing?

Thanks, ***** ***** a play around. The flame rectification sensor is worth checking out and I have been lead up the garden path before now by the air pressure switch. Having said that, I have noticed in the past hour that opening the hot tap at full whack produces hot water no prob which could suggest the pressure switch is not sending the right signal when the tap is opened nomally or slowly.

Plumberpro : Hi , if it is the fan , air pressure switch or flame rectification, it should do it on heating as well
Plumberpro : Check the hot water micros witch is making contact , should be able to see it moving when tap is opened . If the pin isn't coming out far enough. Then that could be a diverted valve diaphragm issue .

Hi, Sorry I had to have a little knap. It's now lookin more like a diverter valve problem as I have raised the central heating thermostat and switched to both ch and hw on demand. The wireles is calling for the heating but no response over an hour or so.

Plumberpro : Ok. What if you now run the hot rap ?
Plumberpro : Sorry , tap

Will wait till Monday to see what Vaillant have to say and when we reach a positive outcome I will rate your answer. So far so good. I appreciate how difficult it is in this particular instance to pin it down. I have had about 4 diverter valves over the lifetime of this boiler and I'm surpised that technology has not come up with something more robust and reliable. Just saw your message. The HW came on smoothly

Plumberpro : Ok , thanks . Hope it goes well . Toby
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Hi . Just wanted to say , change the ntc temp stats aswell , when they start going wrong all sorts of wierdness can start happening , thanks for the rating