Worcester Bosch Oil Heatslave 26/32 loss of pressure - update

[mitchino]

A few weeks ago I asked about pressure loss on my oil boiler and central heating, and decided to isolate the flow and return with lever valves, so I could eliminate it being a leak somewhere on the radiator circuit. After much difficult work in confined spaces, and a few messy solder joints, I have fitted the valves and discovered that the Boiler is dropping pressure. It drops from 1.0 bar to zero in about an hour.

I am mighty relieved to discover I don't have a leak in my radiator circuit, but where could the water be escaping? I can see if I get down on my hands and knees and shine a torch in, that there is water collecting in the bottom and a drip at the back near the heat slave tank. That shouldn't affect the heating circuit though should it?

Got a Worcester Bosch engineer coming tomorrow to service the boiler and hopefully find the fault, but I'm interested to know where the leak could be.

 

[oilhead]

Common place for these to leak is between the heat store and the boiler section, but your W B techie will advise you.

 

[mitchino]

That's exactly where the leak is by the looks of it. It's all looking a bit corroded down at the bottom. Bit worried a new boiler will be required, mind you it is 14 years old.

 

[mitchino]

So engineer says boiler has had it. Leak is a hole in either heat slave tank or the main boiler unit.

He suggested a very temp fix might be to try a sealer. If I try this what do I use and how do I add it to the system?

I was asking him which boiler to get that will be an easy replacement, and he says the equivalent Greenstar, the 25/32, should slot straight in, with the flue in the same place, pipework in roughly the same place and only one extra condensate pipe to deal with.

Is this our best option? Also found a place in Dumfries that sells refurbished Heatslaves, waiting to see how old and how much they are.

 

[mitchino]

Regarding trying a leak sealer - since I know the leak is in the boiler, can I shut the valves I installed to isolate the boiler, then introduce the sealer into the filling loop (thinking of the Fernox aerosol product that comes with a tube that screws on), then run the heating without the radiators so the sealer only goes round the boiler and not the whole circuit?

 

[oilhead]

If you're going to try that route, then isolate the CH and run up on hot water thermostat. This will keep the sealer in the boiler and heatstore. It may provide a temporary fix. I would forget about a refurbished Heatslave. Your problem is not uncommon, and unless you get one with a complete new boiler and heatstore.

 

[mitchino]

Thanks Oilman, do you happen to know if the equivalent Greenstar 25/32 is a straightforward swap?

Regarding the refurbished unit, we might in the future look at an external boiler, or if oil goes back to silly prices, a biomass boiler, so I'm not keen to shell out £3000 for a new boiler that we might not keep that long.

Nothing to lose in trying the sealer I suppose, might keep us going for long enough to make our minds up on the best way forward.

 

[mitchino]

A plumbing firm on ebay is selling an unused 26/32 Oil Combi. It is a room sealed balanced flue version. I think mine is a conventional flue model, but it has a flueless silencer kit fitted. The flue comes straight out horizontally through the wall. Would the ebay model be a straightforward swap, do I need some kind of conversion kit, or is it not going to work?