Bosch Worcester Junior 28I pressure loss

[MancAnt]

Hi all, anyone give any advice regarding our Bosch Worcester Junior 28I .... I have to keep re pressuring it every two weeks ( drops to 0.6- I put it back upto 1.2 and then it drops after 2 weeks).
Expansion vessel was re-pressured earlier this year by the installer . It is in warranty until the end of 2022

 

[Chuck]

Hi all, anyone give any advice regarding our Bosch Worcester Junior 28I

Okay, you're losing a litre or so of water every week. So before calling anyone I'd have a good look round at the radiators and pipework to see it there is any evidence of leakage anywhere.

Next step is to call a heating engineer who'll be able to isolate the boiler from the radiators, etc. and pressure test them independently. Such a test will normally involve isolating the expansion tank to prevent it masking leaks.

 

[MancAnt]

Thanks for the prompt response Chuck, all radiators and visible piping checked and all seems spot on... there is an older radiator in the hall which has an ever so slight to touch spot of water but only a midges bit occasionally and does not drip..more of a slight seep.picture attached of where it seeps from ever sp slightly.

 

[Chuck]

Thanks for the prompt response Chuck, all radiators and visible piping checked and all seems spot on... there is an older radiator in the hall which has an ever so slight to touch spot of water [...]

It's not a sure thing but if it's weeping it may well be the cause of the pressure loss you are seeing. Even if it isn't now, it probably will become a problem in due course at some point. I would suggest you get it fixed and see if the problem resolves.

It's sometimes possible to cure leaking joints of that type by dismantling them and reassembling with some Loctite thread sealant or Plumber's Mate. I'd be inclined to give such a repair one attempt and if it wasn't successful then replace the radiator with a new one.

Edit: P.S. Use the 'Search' box at the top right of the page. There are many 'How to seal leaking thread?' answers.

 

[Scott_D]

Any water at the discharge pipe outside?
Any pipework hidden under floors on the ground floor?

 

[MancAnt]

It's not a sure thing but if it's weeping it may well be the cause of the pressure loss you are seeing. Even if it isn't now, it probably will become a problem in due course at some point. I would suggest you get it fixed and see if the problem resolves.

It's sometimes possible to cure leaking joints of that type by dismantling them and reassembling with some Loctite thread sealant or Plumber's Mate. I'd be inclined to give such a repair one attempt and if it wasn't successful then replace the radiator with a new one.

Edit: P.S. Use the 'Search' box at the top right of the page. There are many 'How to seal leaking thread?' answers.

Thanks again for the response! I think I'll be looking down the radiator replacement route to be. It's like a small pencil head sized minute it of water that I see that doesn't drip if the radiators have not been on for a while to be fair. The boiler is still under warranty with Bosch Worcester until September/October 2022 so I am going to probably book an engineer out under the pressure drops issues as well as surely it isn't doing it any good topping up the boiler pressure every 2 weeks?

 

[MancAnt]

Any water at the discharge pipe outside?
Any pipework hidden under floors on the ground floor?

Hi Sott no water coming out of the discharge pipe outlet outside.. Also my pressure is going upto 2-2.5 bar and I believe it will only come out when it hits 3 bar on the boiler presure gauge or am I wrong?

 

[Chuck]

as surely it isn't doing it any good topping up the boiler pressure every 2 weeks?

Nope, it's a sign there's a leak somewhere. (I have a Worcester Bosch at home, it has never (5+ years) needed topping up other than as a result of maintenance such as cleaning the magnetic filter.)

 

[MancAnt]

Nope, it's a sign there's a leak somewhere. (I have a Worcester Bosch at home, it has never (5+ years) needed topping up other than as a result of maintenance such as cleaning the magnetic filter.)

I have the magnetic filter fitted too. If there are no visible signs of any other leak other than the ever so slight seep of water as stated earlier could it be a faulty expansion vessel or an internal fault somewhere in the boiler? My fitters repressured the vessel back in May and told me to monitor it then .... 😒
He said if that doesn't solve it get it replaced under warranty ??

 

[John.g]

If your fitter repressurised the E.vessel then he should also have checked the pre charge pressure before repressurising, if he did and the pressure is falling from say 1.5 bar to 1.0 bar when cold over a short period then you are losing ~ 1.5 litres, not good, on the other hand if he has set the filling pressure the same as the pre charge pressure then the cold pressure will fall very rapidly even with a tiny leak.