Bubbling Keston 25 Problem - Please help

[StevieBoy]

Well, and it was going so well. The system has been working fine since April.

It's an vented system.

My Keston 25 this morning is making noises like a Mad Scientists Laboratory ... bubble bubble bubble.

Symptoms of the Patient:

1. Only some of the rads are heating up, and at best they're getting luke warm.

1. Going outside to the flue, the bubbling sound is more pronounced and the occasional drip of water is coming out of the flue. The normal condensate drain is working.

2. The low water pressure light is intermittently coming on

1. Boiler has problems igniting.

o About to pop up into the loft to check the header tank.

Any more thoughts on what I should check as apart from this I'm at a loss.

Thanks, Steve

Regards, Steve

[StevieBoy]

If the condensate trap fails, does it make a bubbling noise and reduce the output of the system?

The bubbling noise is coming out of the 'exhaust' vent.

Thanks, Steve

[IMM]

Does it have water in it?

[StevieBoy]

Yup, loads of water, all the rads are full of water + all the bleed points. Don't think there are any leaks as the water in the header tank was nice and 'greasy' from the inhibitor.

Most of the noise is coming from the flue vent going to the outside, sounds like large volumes of air being pumped through water.

[StevieBoy]

Error messages I've had so far are:

1) Ignition Failure. 2) Sensor Failure. 3) Low Pressure.

Oh joys!

Regards, Steve

[Ed Sirett]

What about the pump?

[StevieBoy]

Pump is integral to the Boiler, when it was firing up, you could feel the temperature difference between the flow and return pipes so I guess this is still working?

Regards, Steve

[IMM]

Auto air vent not working?

[StevieBoy]

Not got one of those in the pipework. There are two bleed points in the airing cupboard and neither of those had any air in. Actually none of the rads had any air in, and never needed to bleed any of them under any circumstances, not sure if this is usual/unusual lucky or unlucky!

Have spoken to Keston and they're coming out tomorrow to take a look.

Many thanks to all who have responded, will update if/when they fix it.

Regards, Steve

[Andrew Gabriel]

There's one on the outlet of the heat exchanger, which can be turned on or off.

To me, it sounded like the combustion chamber has built up a significant amount of water in it, presumably not discharging down the condensate drain for some reason. However, that didn't match all the symptoms you reported. It will be interesting to hear what the cause really is.

[StevieBoy]

The cause was (drum roll please) some gunk in the condensate filter thing inside the boiler. As a guide, the engineer said he gets less than one of these problems a month.

Got a full Boiler check into the bargain, water dirtiness (pass), inhibitor (borderline), and tune up of air/gas mixture.

Shame I had to buy a load of electric heaters from Argos to use to keep the house warm, touch wood won't be needing them again but don't have the confidence (or gall) to return them under the 14 day month back guarantee. We'll see how it goes.

At least they came out quickly and the engineer was very pleasant. Counts for a lot.

Regards, Steve

[Andrew Gabriel]

In that case, maybe my guess was maybe right, but I don't see how this could cause low pressure symptom.

[StevieBoy]

Yup, condensate trap. It's on the right hand side about halfway from the top of the unit.

Agreed, I perhaps that whatever was going on in there go bad enough to reduce the flame, as when it was running it was hardly outputting any real heat to the flow. Maybe some of the sensors got wet or did a mild short circuit. We may never know.

Regards, Steve

[IMM]

Sounds like the flue water full of water, hence the gurgling sounds from the terminal. This would impeded flue flow. Did the fan go off and on intermittently?

[StevieBoy]

As far as I am aware, the fan stayed on. Imagine filling a bucket of water, then getting a bit of hose dunking one end in the bucket and blowing air into the other, that's what it sounded like.

(Time to change alias as there's already a "Stevie Boy" on this newsgroup and don't want any confusion "ragworm" it is)

Regards, Steve

[Ragworm The Abominable]

Ah that's better.

What was interesting is that had a nice chat with the engineer, and he told me all about his lovely Keston Duet he'd got ... just a shame that particular model was well outside my budget.

Regards, Steve

[Tony Bryer]

Isn't a Duet just a Celsius and cylinder preplumbed together for ease of on-site installation?

[IMM]

Yep.

[Tim Mitchell]

That isn't the condensate trap, that is the condensate outlet from the heat exchanger. The condensate trap is at the bottom where the condensate pipe outlet is.

How do you get gunk in there anyway? Things crawling down the flue pipe?

[Andrew]

In article , Tim Mitchell writes

How long before condensing boilers become a source of legionnaires disease ?. Or is the temperature high enough to kill any bugs off ?.