Baxi Megaflo sytem not turning on!

JenK

Hi all, hope someone can help!

I have a Baxi Megaflo System 24 HE IE installed for my central heating for less than two years. Recently i've tried to turn on the heating and it doesnt work. I have the water set to heat every morning and this comes on without any problem.

I have a Horstmann controller downstairs in the house. Once i press the boost buttons for heat, nothing happens. The burner light on the boiler doesn't come on like it usually would. I have enough pressure in the system. Nothing comes up on the display to say theres an error.

Any thoughts? Its gona get cold soon!

anthonyos

sounds like a motorized valve room stat or timeclock you need a plumber to find the fault should be straight forward

DGOBS

it's a control issue, ensure room stats etc are turned up.

Calibos

Had a similar problem on the 28 version of that boiler. (The problem actually was nothing to do with the boiler) Upstairs zone stopped working 2 years after the system was installed. Then we thought it might be one of the Myson Zone Valves. With the help of the lads here I was able to narrow down the problem. It was actually the contacts on the Sunvic Controller that were the problem. I don't know if your controller is the same but on the Sunvic the backplate mounting is offset to one side of the unit. If your wall isn't perfectly parallel with the controller casing there can be a gap between the plastic standoff on the other side to the backplate. 2 years of pressing buttons on that side with the standoff not making contact with the wall and allowing the controller casing to torque on the backplate, broke the backplate clips letting the controller pull away from the backplate and some controller pins lost contact with the wiring contacts on the backplate. Not so much that a quick visual inspection would indicate a problem but after all, doesn't matter if the casing and pin had moved 0.5mm or 5.0 mm, if the pins lost contact, they lost contact.

I broke off the bad retention clip which allowed my controller to sit flush to the backplate again and made a custom standoff to bridge the gap between controller and wall on the otherside to prevent the torquing happening again.



Pic shows gap before I made custom standoff

Your problem may be nothing to do with this but its worth checking out before you call a plumber. I figured it out myself after the lads helped me rule most other things out. Apparently the Sunvic controllers had other issues with the PCB known to the industry but I read statistics that a high percentage of returned Sunvic controllers tested OK and lots of reports from people that their replacements also went around the 18month/2 year mark. I have a feeling my discovery explains most of these OK returns and replacement failures 2 years later. ie. the problem people were having with those OK return units were bad connections caused by this design fault in the casing/wall mounting system, the same would happen to the replacements after 2 years when the torquing would eventually also break/bend their retention clips.

None of the lads here had heard that explanation before so you might end up getting a plumber in who traces the problem back to the controller and simply replaces it because the manufacturer has not issued an addendum to their troubleshooting guide. Price of call out, price of new controller and then the same again every 18months/2 years.

Calibos

Calibos wrote: »

None of the lads here had heard that explanation before so you might end up getting a plumber in who traces the problem back to the controller and simply replaces it because the manufacturer has not issued an addendum to their troubleshooting guide. Price of call out, price of new controller and then the same again every 18months/2 years.

In all fairness programmers/timers not fitting on their backplate have been a issue since manfactures started using backplates and it shouldn't be a hardship to identify this fault. It wouldn't be up to the manufactures to determine incorrect positioning of a programmer or any component on a heating system, the fault you describe was happening 25 years ago when the Randell 103 and the like first came to the market.

Calibos

gary71 wrote: »

In all fairness programmers/timers not fitting on their backplate have been a issue since manfactures started using backplates and it shouldn't be a hardship to identify this fault. It wouldn't be up to the manufactures to determine incorrect positioning of a programmer or any component on a heating system, the fault you describe was happening 25 years ago when the Randell 103 and the like first came to the market.

Well thats perplexing then.

After telling the lads that after some further tests where I removed the controller from the backplate and re-seated it, the 'Dead' Myson valve/Zone started working again and the other Myson Valve/Zone stopped working. I figured this meant there was nothing wrong with the Myson Valve/Zones at all. I figured that the fact the controller turned on those 'working' zones fine and there were no glitches or screwed up LCD display meant my Sunvic controller didn't have the dreaded common PCB fault either.

I asked could my problem simply be bad contacts between the controller and backplate.

No one said, "Ah, yes, thats a common problem since these things were invented, have a look at your retention clips and see are they broken/bent from repeated torquing and preventing all your controller pins from making contact. Its an easy fix"

They just kept telling me it was my Myson Valves and/or to call in a plumber. So either this type of problem isn't as common knowledge as you think

or

for some reason the lads just kept not reading the bit where I told them the Myson valve/zone problem had switched 'places' after reseating the Controller even though I posted it several times in the latter part of the thread and thus this common knowledge didn't seem applicable in my case to them.

or

They wanted me to work it out for myself

At any rate, those are the reasons I thought that this was something I had figured out myself that might not be common knowledge in the industry. If its common knowledge I am suprised that Sunvic seem to be as suprised as everyone else about all these return controllers they are getting that turn out to test OK and not have the acknowledged PCB fault. Do they keep quiet because it means they get to sell replacement controllers every 2 years?

You are obviously correct when you say that its not up to Sunvic or other controller manufacturers to determine mounting position of their controllers but you would think they would design their controller casings such that a 2mm gap between standoff and a perfectly well plastered wall couldn't cause such problems.

I googled the OP's Horstmann controller and it also has the backplate mounting offset to one side. In fairness, maybe Horstmann have better retention clips that prevent the repeated torquing breaking/bending them eventually or maybe they have an adjustable standoff.

I only mentioned the problem I had in this thread because it seemed reminiscient of my controller problem which started 2 years after the system was installed just like the OP's. Also because its easy to check for before he calls in the big guns and starts paying out call out fee's.

You are absolutely right in spreading the word but do you think you could convey the same message with "get your connections on your programmer checked as I had problems with mine" :)

It's very hard to fault find via text, I don't know the psychology behind why you didn't get your answer from the "lads" but they post here to help, any heating engineer worth his salt would of come across this;).

DGOBS

Calibos, we can only give advice on information given, we are not there looking at the problem!

The thread you refer to, you were asked repeatedly to get a multimeter an confirm the voltage to the motorized valve to confirm correct working or not, but didn't listen. Once that would have been confirmed as incorrect, then the same with the stat (but you thought TRV's interlocked with your boiler) , then the Timeclock. A competent technician would go through this procedure in minutes, and the fact remained, that a Timeclock junction does not sporadically weaken, it's due to either poor installation like not flat to the wall, or unqualified people taking them on and off in a 'DIY experience', which is usually more likely! You were repeatedly told it could be a time clock issue and maybe it might need replacing! (again I am not there looking at it)

In general I would not advise inexperienced people to play with electrical contacts etc, as I do not want them electrocuting themselves, I have no idea of the level of their experience, so commonly stick to DIY then recommend someone competent for the rest (it's safer)

As for 'missing information' on your posts, well to be frank, they do tend to be on the looooonnnggg side, and meander quite a bit, and as I give up my time here for free, do try to wade through the chaff to get the wheat so to speak, as I want to answer more than one poster in my spare time to help.