Baxi Combi Heat HE 105 Problem

NiCkNaMe

NiCkNaMe

NiCkNaMe

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17 Jul 2005
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Hi Guys,

This isn't my boiler so i'm a little unsure as to how it works!

It is on a timer so I generally do not mess with it. However yesterday the house was a bit cold so I turned it up. Come that night the house was very hot so I decided to turn the boiler completly off. (To the 0 position)

This morning I turned the thing back on, to the radiator and tap position and turned both of the heating dials to medium ish.

However a few hours later the boiler has done nothing (it did make nosie for a while) and the 60 degree C (circular symbol with a triangle in it) is flashing red, and periodically the tap icon is flashing screen, but then returns solid after a bit.

Also the pressure guage is sitting at 0.

I have made sure the timer is not interfering (have set it to permenantly on)...

Any ideas what could have changed over night ?? Should I have not turned the thing off?

Checked on the web and it seems the 60 degree C light when flashing red indicates a pressure issue :s

Would appreciate anyone who has one that could shed a light!
 
Normally there is a filling loop (under the boiler somewhere) where you can top up the boiler with water, your guage should be around 1.5-2.0.

If you dont know jack about boilers it may be best to leave it to someone that does know.....
 
Yeah, i'm not going to touch it - will have to give my dad a buzz.

Just confused how it can be working perfect one moment, turn it off and it buggers up !? Do the boilers lose water? Have had a feel around and can't feel any wet patches.
 
Couldn't keep my hands off it so managed to find a service guide.

I've re-pressurised the system up to 1.5 bar (it reccomends 2.0 bar - but to be safe!)... and booted it up. Seems fine now. We've got hot water and the radiators have kicked in.

I've had a run around to check for leaks, etc but can find none. I've also felt all around the boiler and had a check up and down the pipes. The only thing I can think is we had family around yesterday and they were moaning it was cold (I hate it being too hot..) so I reckon they may have turned a few of the radiators up........!? Which could potentially have lowered the pressure if it was already low... I hope so anyway.

Thanks for the above reply, at least you pointed me in the right direction. :)
 
Check if there's water coming out the overflow pipe when the pressure is normal (1.5-2.5), remember having one boiler that constantly released water through it for no reason in one of the houses I used to manage.

Also just check and bleed any radiators that aren't full to avoid losing pressure if anyone turns the radiator knobs again.
 
Cheers.

I ended up needing to bleed a rad as the pressure was going up to 3.5bar, so I bled the rad that I think someone may have turned on yesterday...it's now sitting happily at just under 2.0 bar with everything being used.

I'll check the overflow now :)
 
Expansion vessel is probably flat. You'll probably need a plumber to do it if you're not very DIY concious but it's a mega easy and quick job. Something I do almost daily and takes about 10 minutes. Just involves pumping it up with air so the water has space to expand into when it heats up. If the expansion vessel is flat then that's the reason the pressure is going to 3.5bar which will cause it to blow out of the pressure relief valve and then when it cools down there is no pressure left for it to start up again (a switch inside stops the boiler firing up if the pressure is too low).
 
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Not by too much. 0.5 to 1 bar increase is acceptable.

If it goes up from 1bar to 3 bar then you need to have the expanssion vessel checked, this can only be done with the boiler empty..It has to be drained!
And if the Baxi boiler above is a 105he Instant then the preheat diverter valve has to be in the open position....The expansion vessel is used as a preheat store..

Mick
 
On my system (not a baxi) if I bleed a lot of air out of the radiators I lose pressure and have to recharge the system via a little valve under the boiler.
 
You do not need to drain the boiler to check the expension vessel.

If the pressure is quickly rising to nearly 3.5 bar then the expansion vessel is probably knackered as the rubber diaphragm has split meaning water is now sitting both sides.

Unscrew cap on top of pressure vessel and release some pressure if just air comes out then its fine, if water comes out then the vessel has gone and needs changing.

Once a PRV has opened to release pressure they are knackered and will normally always pass as they never reseal properly

oh and your biggest problem is you have a baxi - they are a pile of junk
 
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Thats misinformation..

So how do you check for correct air pressure in the expansion vessel when there is a possibilty of having upto 3bar of water pressure exherting that force on the diaphragm inside the vessel??

Not taking manufacturing inaccuracies into account (prv & guage) all domestic sealed heating water system prv's are 3bar not 3.5.

If you get air out of the shroeder (sp?) valve, all that means is that 'maybe' the diaphragm hasnt split! Even with a split diaphragm air can trap in the top of an expansion vessel... where you usually have the valve! And of course you can have upto 3bar of water behind it wanting to push that air out.. Esp if your too lazy to drain the boiler. Again draining the boiler and using a foot pump will determine if the diaphragm has split.

So unless you are doing a diy/cowboy job/diagnostic, if you suspect the expansion vessel is the cause of increased system pressure then drain the boiler and check the air pressure in the vessel against what the manufacturer recommends for the system volume in question..

Quite a sweeping statement to say when a prv has been used it wont do its job again....Maybe thats because lazy plumbers are fitting boilers without adequate chemical protection! Or maybe more profit in replacing unnecessary parts?

Certain Baxi combi boilers come with 5years warranty, perhaps they are confident enough in the build quality to offer this?

But hey what do I know, only been repairing domestic heating systems for 12 years..
 
The old Alfa italian baxi stuff is rubbish, the newer stuff isnt bad, I work for the company that has designed the electronics for em.If you want to talk about bad boilers, I raise you the potts puma :shudder:

That said my money would be on a Worcester or a Vaillant (proper Vaillant not a Glowworm or Saunier duval).
 
The baxi 105e is one of the worst boilers out there.

About 60 - 70% of the jobs i go to are baxis, although the new culprits in shoddy boilers are vokera.

I used to like them but over the last 3 or 4 months have had a load of linea he's go up the swanny and all of them seem to of just gone over the 2 year warranty period.

Worst thing about the potterton puma is the pcb but normally its just the track contacts that have gone so we usually just blob abit of solder back o nthe contacts and they are good to go again.
 
Hi,

Don't want to hijack this thread but there seem to be some professionals who know what they are talking about here.

Could you give me some idea of what lag or latency I should expect in a room stat. That is, if the thing in the hallway is set to 17 degrees celsius what air temperature near the room stat should I reasonably expect to see before the thing triggers and turns on the heating, and what temperature should the air around the room stat reach before it untriggers and turns off the heating again.

I'm finding its about 2.5 degrees celsius each way. Thats 4.5 degrees fahrenheit.

The system seems slow to come on when the house gets a bit cold and stays on too long overheating it a bit.

Thanks in advance and apologies to OP :)
 
The_One said:
Likewise the engineer i work with has 43 years in the gas industry.

Go figure :o
Click to expand...

So are you saying that because somebody you work with has 43 years of 'gas industry' experience, that means 'you' have 43 years of experience too?

Perhaps if it was your work colleague that posted a reply instead of you it would have been a more accurate and concise response?

And because you think that 60-70% of your jobs are Baxi repair work....You think that 60-70% of Baxi boilers on the market are junk? Is this based on poor design, poor installation, poor maintenance or what? Do you think that Baxi would still be in business if that was the case? And now Vokera boilers are shoddy too! Is that because the remaining 30-40% of your work is taken up by repairing Vokera boilers? With these sort of figures you should contact 'Gas Installer' (Corgi magazine)

To me it sounds like you are having a bitch and trying to give advice (poor) trying to use your work collegues 43 years of experience as backup!


EffBee

If your finding that the response time is a bit 'slow' with your room thermostat, you may want to change it for a more accurate digital thermostat. Thats if your sure the stat is 'slow'. And its not a case that the area in which the stat is situated doesnt suffer from 'slow' changes in air temperature..

Modern digital stats are normally around 0.5degress accurate either way, and some of the more better programmable stats (Honeywell for example) have an inbuilt (adjustable in the engineering settings) delay to stop the heating system cycling too often..

Mick

Edit: Which? Reviews top rated combi boilers:

1.Baxi DuoTec Combi 28he
2.Potterton Gold C24 he
3.Vaillant ecoTec plus 824
4.Vaillant ecoTec plus 831
5.Ariston Genus he 24
6.Buderus 600/28c
7.Potterton Promax combi 28 he plus
8.Main combi 25 eco
9.Saunier Duval Thema F24E
10.Vokera Unica 28 he
11.Baxi Platinum C28 he
12.Vaillant ecoTec pro28
13.Biasi Riva Advance
14.GlowWorm Ultracom 24cx
15.Halstead Ace he 30
16.Ideal Esprit 24 he
17.Worcester GreenStar 30CDi
18.GlowWorm Flexicom 30cx
19.GlowWorm 24cxi
20.Worcester GreenStar 30Si
21.Baxi Instant 80he
22.Worcaster GreenStar 24i Junior
23.GlowWorm Ultracom 30cxi
24.Potterton Performa 30he
25.Alpha CD28C
 
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