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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Plumbing Questions >> baxi 105e no hot water https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1139140210 Message started by saspinall on Feb 5^th, 2006, 11:50am

Title: baxi 105e no hot water
Post by saspinall on Feb 5^th, 2006, 11:50am

Hello, first post here, hope you can help.
We have a Baxi 105e Combi Boiler which has developed the following fault. If we do not have the central heating on and we go to use the hot tap, we don't get any hot water. However if we switch the central heating on and then go to a hot water tap, we can get hot water, albeit not as hot as usual. There are no fault indicator lights on, only the usual lights for CH on (when on), flame on and whatever temp it rises to. HW light doesnt light for any event, nor do we get any sound from the pump, if the CH is off and we try for HW.
Is/Are there any simple check I can do before getting in a heating engineer ?

Thanks in Advance

Stuart

Title: Re: baxi 105e no hot water
Post by scotspark on Feb 5^th, 2006, 12:19pm

could be the diafram (the flow switch to switch on the boiler when you run your hot water)

but i am just a spark :)

Title: Re: baxi 105e no hot water
Post by saspinall on Feb 5^th, 2006, 12:25pm

any way to test ?

Stu

Title: Re: baxi 105e no hot water
Post by thescruff on Feb 5^th, 2006, 12:44pm

Before I type it all out have you got the manual and a multimeter

Title: Re: baxi 105e no hot water
Post by saspinall on Feb 5^th, 2006, 12:48pm

I have multimeter, and circuit diagram on the inside of the bolier casing ?
I am a qualified electrician and an electrical draughtsman now so I'm confident with electrics

Stu

Title: Re: baxi 105e no hot water
Post by thescruff on Feb 5^th, 2006, 12:57pm

Then you should be able to do several checks to get to the likely problem.

Have you got the manual and if not send me your email and I'll post one on.

Biggish file so be warned if you're not on broadband

Title: Re: baxi 105e no hot water
Post by saspinall on Feb 5^th, 2006, 1:07pm

thanks, email is manual sent email removed for security thescruff

Ive just had someone round, a mate, and he has spotted that the pin in the diverter valve is not coming out far enough to push the microswitch lever to make the contact when only hot water is on ie no CH, make any difference to your answer.

Would still like the manual though, will be useful for him rather than me.

Thanks

Stuart

Title: Re: baxi 105e no hot water
Post by thescruff on Feb 5^th, 2006, 1:34pm

Could indeed be the divertor sticking although the neon should light in the hws mode which points to the pcb.

You can replace the diaphram although easier to replace the whole valve as can be fiddly

Checks with your multimeter will illiminate the pcb

Title: Re: baxi 105e no hot water
Post by AlanJ on Feb 7^th, 2006, 9:01am

Any chance of posting me the Baxi 105E instant service manual.

Manual sent, email removed thescruff

I have had nothing but trouble with this boiler since new. I did have a copy of the manual but it has gone missing.

Here is a list of problems I have had.

1) A constant high pitch noise.
(The first baxi engineer replaced a rubber seal but this didn't cure the problem)

2) Still a constant high pitch noise.
(The enginner replaced a full part and this cured the squeaking)

3) Just out of warranty and the fan stopped working, the bearing in the fan had failed. I replaced the bearing in the fan but there wasn't enough pull from the fan to operate the pressure switch. I had to replace the complete fan unit. It looks like baxi had problems with the fan as the new unit now has a bigger motor.

4) A few months later and the boiler was switching between filling the instant haet up even when turned off. This turned out to be a dry joint on the circuit board.
(The manufacture of the board had bad quality joints in a few places so these were all re soldered.

5) A few months later and the heating would only work for a few seconds at full power then turn off and continously cycle like this until it got up to temperature.
I pulled all sort of plugs in/out and it sorted out the problem.

6) The next problem I now have is that the pushrods are not moving enough to make the microswitch contacts so It won't always switch back from Hot Water to Central heating.

This boiler has been nothing but trouble.

Is this regarded to be a good boiler in the industry or is the problem that I had an early model?

Title: Re: baxi 105e no hot water
Post by saspinall on Feb 7^th, 2006, 5:25pm

I've bought a new diaphragm but not had it fitted yet, waiting for the plumbing engineer. Good site to go to is http://www.partsarena.net/gas/ which if you install a small piece of software onto your pc, will give you manual, parts list and diagrams for all types of heating appliances.

Will let you know if diaphragm fixes my problem

Stu

Title: Re: baxi 105e no hot water
Post by thescruff on Feb 7^th, 2006, 5:53pm

wrote on Feb 7^th, 2006, 5:25pm:

Hey up stu ;D ;D

I have one of the largest libraries for boiler manuals on the net.

8) 8) 8) 8)

Title: Re: baxi 105e no hot water
Post by saspinall on Feb 7^th, 2006, 5:59pm

Sorry, was only trying to help. I posted that site as my plumber told me the site and it was very useful as it gave an exploded view of my baxi boiler, quoting every single part number.

Stu

Title: Re: baxi 105e no hot water
Post by thescruff on Feb 7^th, 2006, 6:38pm

wrote on Feb 7^th, 2006, 5:59pm:

Sorry, was only trying to help. I posted that site as my plumber told me the site and it was very useful as it gave an exploded view of my baxi boiler, quoting every single part number.

Stu

Its only the standard manual that they have posted on their site and is not downloadable.

They also have a very limited number of manuals although they do have some older ones

Title: Re: baxi 105e no hot water
Post by Lectrician on Nov 12^th, 2006, 7:33pm

A guest has used the 'Alert Moderator' facility to reply to this post in error.

I assume they clicked 'Alert Moderator' instead of reply - or didn't realise they had to register an account.

Anyway - Thought I would post the content here:

Quote:

hi there just read your promblem about your hot water. have you tried reseting the boiler ? it sounds like the diverter valve could be sticking. the reasone you'll be geting hot water when the heating is on is because the heat exchanger is hot from the heating been on and the cold water is been pulled throgh the hot heat exchanger that's why the water isnt as hot as should be. to fix this promblem try to free valve or replace with new.

Title: Re: baxi 105e no hot water
Post by baxibovver on Oct 28^th, 2009, 3:38pm

Please Help,
I have Baxi 105e combi boiler approx 3 years old when you run the hot water for approx 3 mins it the flame cuts out and you then get cold water after approx 1min it then powers up starting the whole cycle again resulting in a luke warm bath. The central heating side seems ok could anyone please point me in the right direction.
Thanks.
:'(

Title: Re: baxi 105e no hot water
Post by thescruff on Oct 30^th, 2009, 9:50am

Best to call in an RGSI.

Title: Re: baxi 105e no hot water
Post by wozzy on Nov 22^nd, 2009, 10:58pm

out of interest what is it with the baxi 105e?
was there incredible numbers sold and thats the reason there are so many probelms posted about them? or are they just the most unreliable boiler ever made?

Title: Re: baxi 105e no hot water
Post by CWatters on Nov 23^rd, 2009, 9:06am

I believe whole housing estates were kitted out with that boiler.

Title: Re: baxi 105e no hot water
Post by thescruff on Nov 24^th, 2009, 1:34am

Bg's favorite bean can, yes they are rubbish along with quite a few other, made to fail trash.

Title: Re: baxi 105e no hot water
Post by The_Trician on Nov 26^th, 2009, 2:56am

I must say that since I changed the pump on mine that I've had no further problems with it.
Symptom was the same - no H/W.

Had the boiler fitted back in 2000, and it's still going strong, despite me fiddling around with it from time to time!

Hope my glowing reference hasn't tempted fate!
TT

Title: Re: baxi 105e no hot water
Post by sparky on Jan 11^th, 2011, 11:37am

Hi
this is my first time on this forum but i was wondering if you could help me, i have moved into a house with a baxi instant 105e boiler just recently i can not get any hot water but the heating works, i have no manual with the boiler could any body please have a copy they could e mail to me so i can try some fault finding.
cheers

Title: Re: baxi 105e no hot water
Post by The_Trician on Jan 11^th, 2011, 5:49pm

QUOTE from another site

Quote:

I just stopped getting hot water overnight, there was no problem with the central heating and also there were no fault LEDs showing.

When you turn the tap on a little plunger should come out of the diaphragm and push the micro switch to make the hot water LED come on and start heating the hot water. This stopped working, the fault was the circular rubber diaphragm, about 3inch diameter and ~£10, was perished.

It is really easy to change, just remove the small pipe going into the top of the diaphragm and then the 8 screws at the front. Make sure you fit the rubber thing in the correct way and reassemble everything in reverse order to dismantling it.

Hope this helps!

For reference the other problems I have had:

The 80degC LED was flashing, this turned out to be the central heating temperature sensor, ~£14 and you do not need to drain the system.

The 70degC LED was flashing, this turned out to be the hot water temperature sensor, ~£14 and just turn off the mains water tap.

Everything stopped, this was the main PCB, it was easy to change and cost £96.

All parts and drawings at www.partsarena.co.uk/baxi

Title: Re: baxi 105e no hot water
Post by TheGASGUY on Feb 10^th, 2011, 9:22pm

Have you fixed the problem? do you hve inhibitor? would also clense the secondary HEX.

Title: Re: baxi 105e no hot water
Post by thescruff on Feb 11^th, 2011, 12:23pm

Manual download.

http://www.ultimatehandyman.org/PDF/Baxi/Baxi-Combi-Instant-105-HE.pdf

Title: Re: baxi 105e no hot water
Post by Wayne B on Feb 11^th, 2011, 9:07pm

Flow sensors and diaphrams on these are usualy the things that go wrong also leaking O rings if it wasn't flushed properly. :)