We have a Baxi boiler that is failing every day or so, going straight into error code e168. The problem is baffling our local British Gas engineers who have replaced parts (pump, 3-way switch for water, PCB twice) and say the problem is now most likely caused by system blockages and needs flushing by them to the tune of £720 (only the boiler and controls are covered as the pipes and rads are not part of the breakdown cover I have with them!). Rather than me try and explain what happens to them and anyone reading this post, I set a webcam up to record the pressure and temperature gauges, the event in question usually happens after heating has been on for a few hours, but sometimes it can go for days without problem. Our attention was first drawn towards something being wrong when we heard the boiler banging and clattering back in February at which time I refilled with water as pressure had dropped to almost nothing, according to gauge. Note: one of the BG engineers says there is no problem with pressure vessel / diaphragm or PRV as he checked all. When the system is running all seems fine with radiators getting hot. There have been no system mods (like re-positioned rads) done in at least the last 2 years, so nothing has changed recently that would ring my alarm bells. The video is here, watch what happens at about 12 seconds in. Any advice appreciated.
Intresting, no nothing about baxi boilers, had a look on Baxi site, long list relating to E168 error code. http://www.baxi.co.uk/trade-resources/technical-advice/error-codes.htm#horizontalTab4 I put my money on Diverter Valve (cartridge sticking), don't whether you can get a service kit, or it's a complete new valve. Some one on here will know.
I'm pretty sure this model (System type HE) does not have an internal diverter valve. We have a diverter in airing cupboard that flows to heating or hot water cylinder.
Long day, your correct,thinking of the wrong model, facia layout almost identical on others in range confused me, but could the valve still be sticking?
Blimey, that's sudden! It does appear that something shuts off/blocks the boiler flow very suddenly, and there can't be too many components that will do that. The still-running pump then possibly causes the sudden pressure jump, but I guess that could only happen if the pump is on the return, pumping in to the boiler, with the diverter valve on the flow? The flow blockage - with the boiler still running - will cause the very sudden temp rise, and over-heat thingy. If the diverter valve is external, that makes it even easier to replace, so KIAB's suggestion sounds good to me if what you are looking for are ideas to try. All of the above is pure speculation of course...
It could be restricted heat exchanger, AAV in boiler, exp vessel to small, boiler stat faulty, it's certainly not the PCB? Or 3 port valve?
OK just read the manual, its the Baxi Megaflo HE model. There is indeed an integral auto bypass inside the boiler, well at least according to manual in front of me. My installer also just called me back, he fitted the system about 8 years ago, though he's since retired and taking well earned rest however the first thing he told me to get the BG engineer to check when he returns is the spring/valve in the auto by pass pipe. Now, this is rather worrying me as my retired installer (40 years BG eng) pointed this out without thinking too long but when the BG home service engineer was last here checking everything on the system, he refused to accept the fact that the boiler was fitted with an integral by-pass and told me that the only bypass on the system was the hall radiator (no trv). Is this part of the power flush over sell strategy... I hope not! BG are due back today so it will be interesting to hear what they say. They have to return anyhow as water is leaking from service valve after last visit when they checked expansion vessel. (Releasing pressure by activating the PRV, which I have since read is absolutely frowned upon as it probably wont reseat fully). So this auto by pass might be duff, lets wait and see. What do you guys think?
If they have activated the PRV to release pressure then they are liable to replace that valve FOC. You should point out to the BG engineer its a Pressure Relife valve and NOT a drain off point. Like I said before have them look at the Bypass valve and probably replace it.
Nice good competent engineer visited and looked into bypass operation and how its supposed to function on this particular model, which is a system boiler as opposed to combi, which seems to make a difference to how the bypass operates. He called Baxi and it appears that this bypass pipe is in fact nothing more than a loop as opposed to a diverter. Still seems kind of strange to me though that you would permanently recirculate hot water.
Frosty, that's good news you have the original installer giving his input. He probably fitted many of these during his career, so will be very familiar with them. The current BG 'engineers', on the other hand, will likely have a basic knowledge of many different boilers, but detailed knowledge of very few... That's not to excuse them from their responsibilities, of course; if they have been replacing expensive parts (pump, 3-way switch for water, PCB twice...) on a 'suck-it-and-see' basis, then they can be held to account over the final bill. Is BG charging you for each 'repair' or are they on a fixed-price maintenance contract (I really hope the latter)? As said above, using the PRV to release the system water is very silly. There are many threads on this forum that attest to that, so they need to replace it FOC. And, if it turns out that the fault here is in the built-in by-pass - which they maintained didn't even exist - then they can forget charging for all the other components too. Anyways, let's not jump t'gun too soon - there could, of course, be another issue here. But, if when they come back and you tell them there is a by-pass inside and they check it and find it was the cause, then you can happily tell them to hand over all the payments made to date. Or you will use MoneyClaim.gov - and you will almost certainly win.
I don't need to worry about the cost of all the parts and labour as I'm on a service contract with zero excess in event of a claim. I must say that the engineers who have visited, bar one, have been extremely helpful. It looks like I'm going to do a mains flush of whole system at Easter as they are convinced there is a blockage somewhere downstairs as pipework is old 10mm micro bore from a manifold. As far as I'm concerned a powerflush will be a last resort. I'd rather crawl under floors and replace sections of piping than pay hundreds of £'s for someone to stick a power hose on the end of a piece of pipe. A blockage however still doesn't explain the e168 code as the auto-bypass is designed for exactly the reason of allowing a constant flow through the heat exchanger regardless of system pressure variables like blockages and closed trv's i.e. the boiler should still be able to run (albeit for a short time) without overheating instantly.
Anything to be gained running a cleaner Fernox or Sentinel like through the system for a week, (won't clear a blockage) just ran some through the system here prior to me replacing a few radiators, amazing the crud & water colour that came out, flush the system a few times. Thankfully, I don't have microbore pipework, horrible stuff.
please explain Is your system boiler dumping from its built in PRV when fired up? Do you have split htg zones? Underfloor heating? Have you checked your room stat turns boiler off when satisfied? The expansion vessels in system boilers are notoriously too small, check charge pressure/add additional expansion vessel, A auto bypass is required and I would recommend one be fitted away from the boiler in cyl cupboard before all zone valves, you also need a radiator with no TRV in room with room stat fixed open, Feel free to give me a call I am happy to help, Tony 07542193857
.... the E168 saga that has now dragged on for over 2 months, seems to be finally at and end. It turns out that an incompatible pump was fitted to the boiler back in February, when we originally reported kettling noises and sudden pressure fluctuations. I might be being unfair (hindsight of course is a wonderful thing) but installing the wrong pump and then immediate promotion of a flushing service quoted at £720 with no guarantee if it doesn't in fact solve the problem of circulation issues, does to me seem rather a nice way to make a bang tidy profit, then put the right pump back on.... Of course this could all be completely coincidental and simply that fault diagnosis procedures were being followed, I don't know but we're just happy to not coming back home to no heat or guessing if we would have hot water in the morning. The 'problem solving' engineer, who had never been before, even showed me a page on his portable laptop that clearly had a big red cross through a diagram of this pump in relation to the boiler model, apparently it was for the combi version and ours is a system version so the page needs updating. So glad we had no excess and zero to pay I guess the moral of this tale is to take out their cover but make sure you don't have a penny to pay if there is a fault and just keep calling them out until you finally get sorted.
Blimey! What a story. As you say, good job you weren't paying for it, or it would have been thumbscrews and small claims court...
Forums
Facebook
Twitter
You Tube
Instagram
Shop