Hi My Modena 80E boiler cuts out when I am running the hot water so the hot water gets hot then cold then hot then cold. The heating is fine so it is only the water is there anything I can do or should I call someone in to look at it?

A Potter, January 2008

This is a common part failure on the Modena 80 and Modena 102.
The cause will be failure of the DHW temperature sensor which can, and usually does go out of tolerance. The sensor is located on the DHW outlet just before it passes through the bottom plate of the boiler.
Part number is 800320 and costs around £7.40 +VAT.

It's straightforward enough to replace. Shut off the cold supply and electrical feed to the boiler, open your hot taps to drain the pipework, then simply unplug the old sensor, unscrew it, then replace with the new item.

Steve, February 2008

you could try cleaning the fan vanes with a tin of comressed air , this is an easy check, turn off the mains power before removing the fan

mike b, January 2008

it could also be the domestic hot water stat, again this is in the waterways, i woundn't attempt to do this yourself as you need to know how to carry out the tests using a multimeter

mike b, January 2008

check the flow sensor, it is fitted at he bottom right hand side of the boiler and has a black cap wit an electical connector coming off it. it is part of the water ways.

mike b, January 2008