Home » How to repair your Sime Combi Boiler Top up the Pressure / Repressurise ALL 02
SIME BOILER NOT WORKING Sime ALL 02 fault code low water pressure. AL 02 Today I’m going to show you how to fill up or top you a Sime boiler, or S-I-M-E boiler. I’ve come to do a service on this boiler today. I’ve got to drain the boiler down anyway so I can top up the expansion vessel. I thought I would take that opportunity just to do a short video on how to refill the boiler.

If your boiler’s not working, then there’s a good chance that this is what the issue would be. This is one of the biggest call outs we get, for low water pressure. What I’ll do, if we have a look now, I’ll show you the pressure gauge and then I’ll show you the pipes underneath, and I’ll show you how to top it up.

On this boiler, it’s got a digital pressure gauge there, which shows 0.9. So that’s 0.9 bar. I’m going to lower the pressure in this, and then I can show you how then to refill it. Then we’ve got a filling loop here. How this filling loop works on this, this pipe here, this is the cold water. And what we want to do is we want to put some more cold water into the heating system. And then this pressure then would go up.

So, if we have a look on there, this pipe here is the central heating pipe, and that’s teed in to there. All we need to do is open the valve on this one, and it’ll allow cold water to go into there, and then into the heating system. You’ve got to be really careful not to push pressure in. If you put too much pressure in, you could do more damage to the boiler.

What I’ll do is I’ll show you how to do that now. I’m just going to use the filter, just to adjust the pressure. And then we can see on there, it’s gone red on the front here. And there’s no pressure now in there. Now what we’ll do is we’ll refill the boiler, and I’ll show you the pressure going back up.

All we need to do now is open this valve here, and as I said, just remember, do not put too much pressure in. We only want to get to just over one bar on that gauge there. Sometimes they’ll have a manual gauge as well. The manual gauges are better, because you can do it when there’s no power on, but we’ve got what we’ve got.

Right, so we’ve opened that now. And as we open that, and you don’t need to do this quickly, just take your time, now we can see pressure gauge going up on there. I’m going to do it to about 1.2 and then I’ll turn it back off. And then we see there, the boiler will now work again.

And that’s how to top up or refill your Sime boiler. Thank you for taking the time to watch my video, how to fill up or re-pressurize your Sime boiler when it’s not working. Thank you.

Allen Hart

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