My Dad’s boiler and Rayburn packed in this week. Turns out they’ve been fed with water so no surprise they stopped working. It seems that the tank has a known (to the supplier) fault with the outer cap. This is how the water got in. However the oil delivery guy had left the inner cap off which would otherwise have kept the water out of the inner tank.

So does one point the finger at the tank supplier for not notifying people of a known issue? Ought the delivery guy assiduously replace all the caps? Should my Dad ensure the cap is leak free and in place? Or s the blame shared and Dad sucks up the cost?

I’ve had a driver not fit the lid correctly, now I always check it. Not sure if you can blame the driver, someone else could have removed it (unlikely but you never know).

i) did the tank supplier/manufacturer make your dad aware of the fault? if not, then their fault (how could anyone else be reasonably expected to know?)
Ii) if your dad was aware of the fault, did he make the delivery driver/company aware of it and how? If he did, then you could argue it was their fault, but seeing as your dad was aware of the (unusual) fault, might be reasonably argued to share some of the blame for not putting a reminder sign or checking it himself, as it could be reasonably foreseen that this might occur.

Tbh, you’ll have a hard job proving that the water in the tank wasn’t ‘historical‘ – the outlet from the tank is usually raised a few inches as a sink for sediment and water, so must have been a lot of water in there. That said, the cap should have been replaced, so might be worth appealing to the oil company. If they value continued custom I would hope that they would make a contribution to having the boiler/rayburn serviced and relit (do it in that order – serviced and then relit). `they might want to cover the cost with account credit – cheaper for them to do so. Bad luck, been there. Horrible situation.

Tank driver must replace filler cap if present and working. Go to the oil company.

Tank will have to have water drained out, easy enough with a pump and rigid tube.

Oil pump in boiler and possibly Rayburn (if pressure jet burner) Will need to be renewed and re-set to boiler spec. It may work for a short while without renewal but the bearings will be rusty and will start squeeling.

However the oil delivery guy had left the inner cap off which would otherwise have kept the water out of the inner tank.

He needs a slap for that, ask the delivery company if he leaves every inner cap off.

No idea how you’d apportion blame, so just get it all fixed and see what the bill is (and is it worth your Dads time to get someone to pony up).

He wasn’t aware of the fault until he rang them to query how water might have got in and they admitted that it was probably the faulty cap. However the cap is not covered by the warranty so they’ve so far charged him £180 to pump out the tank and the new cap will be £90 plus the vat.

On what day does the window cleaner come?