Vaillant ecotec plus 831 intermittent hot water repair sheffield

vaillant ecotec plus 831 intermittent hot water repair

This was a service and repair I did yesterday in Rotherham on a Vaillant ecotec Plus 831 Combination boiler. The customer said the hot water was working intermittently, running hot and cold and seemed to be worse at the taps in the bathroom.

They said the hot water had gradually got worse over the last few months and now was unusable. When it comes to hot water repairs on Vaillant ecotec combination boilers or combination boilers in general, the issue usually comes down to one of two issues. Either the boiler doesn’t know the tap is running, or the actual process of heating the water up is the fault.

When the hot water consistently runs cold on a combi boiler, it usually means the mechanism or switch that tells the boiler the tap is running is faulty and the boiler doesn’t know the tap is running, hence the water runs cold.

Vaillant ecotec blocked plate heat exchanger

vaillant ecotec plate heat exchanger

When the hot water runs hot and cold and is inconsistent this usually means that the actual process of heating the water is going wrong for some reason. On an older Vaillant ecotec combi boiler it is easy to determine if the boiler thinks the tap running as a tap symbol should appear on the display if it is a Plus model. On the Pro models the green led will be flashing. On later models you get a tap symbol on both pro and plus models. One can also use status codes to determine what process the boiler is in.

The boiler not responding when the hot water tap is running can usually be attributed to a faulty flow sensor(aqua sensor as vaillant likes to call them) or faulty printed circuit board which i have come across before.

Vaillant ecotec blocked canoe filter housed in flow pipe manifold

vaillant ecotec blocked canoe filter housed in flow pipe manifold

The hot water temperature fluctuating on a Vaillant ecotec combi can be attributed to several things including a blocked primary heat exchanger, blocked plate to plate heat exchanger, blocked flow or return pipes on older models or a blocked canoe filter. In some cases a weak pump can attribute to the problem.

The first thing I did with this particular boiler was remove the plate heat exchanger to inspect it. I also felt the internal return pipe rubber hose to see how soft it was which can be an indication as to whether it’s blocked, plus it was leaking slightly and needed replacing anyway so I removed it.

I removed the pressure sensor to have a look at the canoe filter to get an idea if that was blocked. I also removed the internal flow pipe as the customer wanted to replace this one as well.

The plate heat exchanger was blocked and was subsequently flushed out with acid to restore it. The flow and return pipes were partially blocked and were replaced. The canoe filter in the flow pipe manifold was blocked and replaced. Theses filters usually break and don’t come out easily to my surprise this one came out in one piece without me having to remove the flow manifold.

Blocked canoe filter inside flow pipe manifold

blocked canoe filter inside flow pipe manifold

Blocked and leaking internal rubber return pipe

Richard contact numberemail address

Areas where I can repair your Vaillant ecotec plus combi boiler

areas that are covered

I cover a large part of South Yorkshire including most of Sheffield, Rotherham and Barnsley. I also cover a small part of Doncaster.


I cover most of Sheffield including central Sheffield, Chapeltown, Ecclesfield, Grenoside, High Green, Oughtibridge, Thurgoland, Wortley, Aston, Aughton, Swallownest, Todwick, Hillsborough and Stannington.


I cover the whole area of Rotherham including central Rotherham, Brinsworth, Catcliffe, Canklow, Masbrough, Treeton, Whiston, Greasbrough, Kimberworth, Thorpe Hesley, Rawmarsh, Wentworth, Bolton-on-Dearne, Goldthorpe, Thurnscoe, Wath-on-Dearne, Mexborough, Swinton, Kilnhurst, Hooton Roberts, Ravenfield, Thrybergh, Bramley, Hellaby, Maltby, Thurcroft, Wickersley and Braithwell.


I cover most of Barnsley including central Barnsley, Birdwell, Stairfoot, Worsborough, Kendray, Ardsley, Athersley, Monk Bretton, Lundwood, Royston, Brierley, Cudworth, Cortonwood, Great Houghton, Shafton, South Hiendley, Brampton, Darfield, Wombwell, Hemingfield, Elsecar, Hoyland, Jump, Barugh Green, Cawthorne, Darton, Dodworth, Gawber, Mapplewell, Pogmoor, Staincross, Wilthorpe, Worsbrough, Thurnscoe and Tankersley.


I cover a small part of Doncaster including central Adwick, Conisborough, Edlington, Warmsworth and Mexborough.