oil techs please comment

[manortim]

got a customer who i replaced their old 50-70 danesmoor water jacket 25months ago.

system wasn't exactly clean so it got a flush through to remove 90% of muck and a magnaclean fitted on return of CH.

its got 35mm primary's unpumped to the cylinder and 28mm flow return pumped via 25/85 for CH.

it has started to leak from the water jacket.

now, Worcester claim it is because the return temp was too low causing condensation build up in the burner chamber, which leads to corrosion of the jacket and causes a leak. BUT it has a 22mm bypass gate valve that was open 1/4 way and the boiler temp was on its 2nd from highest temp setting. return temp from both CH and cylinder are above 60degrees.

now i have seen this many times on condensing oil boilers but it has ALWAYS caused the water leak inside the burner chamber from the inner part of the jacket, not the external part of the jacket.

they also state there is no warranty on water jackets unless fitted by them!

comments please......

 

[gremlin16]

they also state there is no warranty on water jackets unless fitted by them!

Typical WB answer.

Seen a couple of heatslaves jackets leak after 3 years, allways on a welded seam.

 

[DeltaT2]

Worcester Tupperware Bosch are talking sh.te as always!! There's no way a water jacket should leak after on two years, condensation or not!
Yes, this can happen on HE oil boilers as you say; if the Delta T on the F&R is wrong. But 4mm steel water jacket corrode through in two years, no way.

I think you may have got the spotty faced yoof in their Tech dept. Why not speak to your local WB rep, & ask him for the name/phone number of a senior guy in their Tech dept.??

We have had loads of Grant oil boiler with leaking water jackets & they've been 'text book' installation.

 

[Onetap]

1) Worcester claim it is because the return temp was too low causing condensation build up in the burner chamber, which leads to corrosion of the jacket.......................

2) BUT it has a 22mm bypass gate valve that was open 1/4 way and the boiler temp was on its 2nd .....................

3) they also state there is no warranty on water jackets unless fitted by them!

1) Back-end corrosion, caused by acidic condensation forming at the return connection (coldest point) within the combustion chamber. It won't cause corrosion anywhere else, unless there's some mechanism collecting the acid and depositing it elsewhere. It's lovely to be patronized and treated like a gullible idiot by a manufacturer, after they've got your money; not a mistake you'll be making twice, I'm sure.

2) This wouldn't guarantee an adequate return temperature, you'd need an automatic valve or a shunt pump. You'd usually only get condensation during start up which isn't significant. If there isn't corrosion around the return connection, then it wasn't the problem.

3) That would have been stated in the terms and conditions, brought to your notice before you bought it. If it wasn't, they can't now slap on extra terms after you've entered into a contract, unless you agree to it. The contract is with the vendor (not the manufacturer, unless bought directly from the manufacturer).

Ring back and politely ask to speak to someone competent in the technical department. This is heading towards a County Court Summons, IMHO.

 

[DeltaT2]

got a customer who i replaced their old 50-70 danesmoor water jacket 25months ago.

system wasn't exactly clean so it got a flush through to remove 90% of muck and a magnaclean fitted on return of CH.

its got 35mm primary's unpumped to the cylinder and 28mm flow return pumped via 25/85 for CH.

it has started to leak from the water jacket.

now, Worcester claim it is because the return temp was too low causing condensation build up in the burner chamber, which leads to corrosion of the jacket and causes a leak. BUT it has a 22mm bypass gate valve that was open 1/4 way and the boiler temp was on its 2nd from highest temp setting. return temp from both CH and cylinder are above 60degrees.

now i have seen this many times on condensing oil boilers but it has ALWAYS caused the water leak inside the burner chamber from the inner part of the jacket, not the external part of the jacket.

they also state there is no warranty on water jackets unless fitted by them!

comments please......

If anything I'd suggest you'd always have a certain amount of residual heat in the water jacket - what with the gravity Hot Water F&Rs. But of course this doesn't take into account what the circulation pump is doing??!!

I too have never seen corrosion caused by 'cold' Return water on the exterior of a water jacket.

Another type of appliance that suffers from these corrosion faults is Solid Fuel appliances. A common installation fault on them; is fitting only one pipe or indeed cylinder stat, rather than fitting a Hi/Lo pipe stats on the gravity F&Rs, and the circulation pump remains on when the appliance is cold.

 

[oilhead]

Have seen it many a time, but not in such a short time. Also, not that often on such a small boiler, unless it is on a very large system. It is usually associated with too large a boiler when the heat produced cannot be circulated so the boiler cuts off. It also can be prevalent on gravity DHW circuits.
I would suggest to Worcester that the problem may be with the fact that they have sold you a quite old water jacket which has probably developed corrosion in stock in probably adverse storage conditions.