Baxi Duo-Tec 28H - Error 119

7 Jan 2008
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United Kingdom
Hi all

Our Baxi Duo-Tec 28H combi boiler threw an Error 119 at me yesterday. It's done this before, every few months, and as the error code means low pressure, I've simply had to repressurise and all has been well. Yesterday, however, the pressure gauge sat at 1bar when the error message occurred and repressurising, even modestly, caused the pressure gauge to move over about half an hour almost into the red, at which point the boiler stopped working showing Error 119 (even though this seemed to be an issue of over-pressure).

On the advice of our gas engineer, I then used the Pressure Relief Valve to let out some air, lower the pressure back to about 1.5bar, and get it working again. The first time, it worked for a few hours, then another Error 119 on low pressure (still at 1.5bar, which shouldn't be 'low'). There is no detectable leak and it's not sinking lower than 1.5bar. I went through this cycle of repressurising, then depressurising after half an hour, about three times. Each time it eventually stopped working with an Error 119 message.

Today the pressure is stable at 1.5bar, but it's stopped and stuck on Error 119. I can fill it up a little with water, to around 1.75-2bar, but this does nothing. If I then turn the Pressure Relief Valve it seems to release water not air, so I've stopped doing this. I can't get the boiler to start at all.

Does anyone have any ideas what might cause this, and what the solution might be?

Thanks for any pointers!


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Stop messing about with your boiler ! you and by the sound of it your heating engineer do not know what you are doing or talking about.
i would say you have now broken the pressure vessel with the tinkering! Even if replaced im not sure this would cure the existing fault? Get your 'gas engineer' to check the charge in the existing pressure vessel.
Okay, thanks.

Certainly I have zero expertise with boilers. Therefore I can only trust the gas engineer (Gas Safe registered) when he advises me. Of course, he may well be wrong. Perhaps what he advised will even cause further problems. But as I have zero expertise I cannot judge that.

So I ditch him and get another engineer in, who tells me something else. And because I don't know anything about this, I have no way of judging his expertise either.

I'm sure you understand the predicament.

Perhaps you could suggest what might have been the fault that caused the initial problem. And what can be done now - presumably even if I have broken the pressure vessel and it's replaced, I'd still need to know what the initial fault was in order to get it fixed.

I'm here to try to educate myself a bit so I can make some informed judgments about what others say and what I should - or shouldn't! - do.

Thanks for any further constructive guidance.

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The pressure releif valve is a safety device, not a drain point or air bleed point.

It should never be used for either as muck in the system may then clog the seat and it will let by.

I can only guess from here, but it seems that some muck has blocked the pressure gauge and you need a new one, but this can only be found out by someone in front of the boiler.

I obviously don't know your gas man from from Adam, but it does sound as though he has given rather bad advice.

If you can, ask around friends and colleagues for another RGI who is recommended.
is it not just those crap water pressure switches baxi use on these things? seems obvious it's blocked or broken. takes two seconds to confirm.
Thanks for these two replies. He's replaced the pressure switch and cleaned debris from behind it (on my advice, having read this and other forums!), and the boiler seems to be running okay. I hope no damage was caused to pressure relief valve or expansion vessel by earlier actions.

This guy was recommended, but self-confessedly doesn't know this make of boiler. I agree that's a problem. I'll try to find someone who does.



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