Worcester Heatslave 20/25 Lockout

11 May 2015
Reaction score
United Kingdom

We have a Worcester Heatslave 20/25 boiler and as of this morning hot water ceased to come from the taps!

I read the manual and it appears that the lockout light is indicating it cannot fire up. My first instinct was to check the oil in the tank, which was absolutely fine and has been for a number of months.

I did some more reading around and understand you can bleed the oil line manually. The manual instructs to only press the Lockout Reset button twice, which we have done.

If I was to attempt to bleed the oil line manually, could I risk doing further damage to the boiler in attempting to fix it on the cheap?


Sponsored Links
Unfortunately Paul, there's quite a few possibilities why the burner has locked out.....if the oil supply has remained constant and untouched, it could be a pump solenoid fault, photocell, motor or whatever.
When you go for start up, the burner should purge with fresh air before the fuel is turned on.
What can you hear?
John :)
Sounds like my luck is out then.

I have tried bleeding the oil through the nut a few times, but don't get anything at all which is worrying.

The motor starts, it tries to fire up for several seconds before just ceasing. No other noises if I'm honest.

Looks like it's a plumbers job.
Sponsored Links
If your opening the bleed port and nothing's coming out, you have a problem with blocked filter, fuel to low or a fire valve has popped.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local