Two Problems With Worcester Bosch RD628 Boiler - Are They Related?

Maxes_Party_Planner

I’ve had a couple of longstanding issues with my Worcester Bosch RD628 boiler which I confess should have been addressed earlier. (The boiler's about 6/7years old and has been serviced every 2yrs and is also due a service).

Firstly, the boiler continuously pressurises up to and beyond 3.5Bar with a continuous flow of water coming out the overflow pipe.

Secondly, the boiler frequently trips out when I try to switch the heating on, either directly or via the timer or indeed when I'm just running the hot water taps. At first the boiler only tripped out now and again but over time this has got progressively worse, to the point that sometimes it can take up to an hour of pressing the reset button before it decides to switch on.

I recently called an engineer out from a local firm who said the pressure problem was likely to be the expansion vessel. He re-pressurised the vessel but the tripping out problem however seemed to have him puzzled. Typically, while he was there, the boiler fired up first time, every time and he seemed to be trying to convince himself the two problems 'had to be related' as he couldn’t think of any other reason why the boiler would trip out.

He said to keep an eye on the boiler pressure and if it went back up to 3.5 Bar (which it has) then it would need a new expansion vessel. He explained this would be costly purely in terms of labour as the boiler would have to be dismantled and taken off the wall in order to fit the new vessel.

I’m about to get in touch with them again (their service was very good first time around) to get an idea of how long this is likely to take and how much it is likely to cost (I previously paid £55+VAT an hour for labour and have also tried, unsucessfully, to look online for the price of a pressure vessel)

I was wondering if anyone had any views on whether the two problems are indeed related and whether both are likely to be resolved just by changing the expansion vessel and also what costs I should reasonably expect to pay.

Any advice & opinions would be much appreciated.

Former_MSE_Alana

Hi,

We have received this response from Worcester, Bosch Group:


"Hi, this is Worcester, Bosch Group

Our technical team can help with enquiries - please email technical.enquiries@uk.bosch.com or call 0844 892 3366.

We look forward to helping you."

gavleash

the pressure problem is due to the fill valve passing, the higher pressure mains cold water is over pressurising the heating system resulting in the safety valve blowing

keystone

gavleash wrote: »

the pressure problem is due to the fill valve passing, the higher pressure mains cold water is over pressurising the heating system resulting in the safety valve blowing

Assuming, of course, that it isn't a knackered EV.

Cheers

gas4you

If you press the air valve on the expansion vessel and water comes out, then it is definately knackered.

You do not necessarily have to have the one on the boiler replaced. If you have a suitable location you can have an external EV fitted. This should cost a lot less than having the boiler off the wall.

It sounds as if by tripping out, you actually mean it will not light? Two different scenarios really.

gasbag1602

Hi there there is a couple of known problems with this boiler, 1 being the main heat exchanger passing internally from the cold main in to the heating circuit hence the pressure rise. The other one is the main PCB which intermittantly stopps the poer to the fan and causes strange faults leeding to locking out.. I hope i am not right because these parts are not cheap but its dificult without seeing the boiler... hope this helps

gas4you

If the last post is correct, your best bet would be to call Worcester in on a fixed price repair. I think it is about £240 all in and for up to 3 major parts.