Recent: Home max fs506x?

Mend > Home Heating Systems

Mend Baxi Combi 105HE Boiler Thermostat

How can I fix my Baxi Combi 105HE boiler?

The heating has suddenly stopped working today. We have a combi boiler and the hot water still comes on instantly when we use the taps.

We have recomissioned the thermostat (Sunvic TLX7506 RF digital room thermostat) to ensure the signal is being received and that seems ok. The thermostat is showing that heating should be on.

The timer is set correctly and there are no fault lights flashing on the boiler. We have also increased the pressure as this had fallen below 0.5. The only thing that doesn't seem right is that the TEST button does not make the boiler fire up (usually it does).

Can anyone help??

Tina
January 2009
i have the same problem this moring - i called Sunvic Controls Ltd who make this thermostat today and your boiler is okay its the receiver thats broken so you will need a new one. Suggest trying ebay on B& Q - large stores only - start at about £60.

hils
March 2009
if the dhw pin was stuck out the the tap would be lit up on the boiler,i would isolate electrics drop front cover remove pcb cove and put a link on the room stat wiring to be sure theres no problems with externals,unless the radiator light is coming on with the programmer

jim
February 2009
what area

b
January 2009
Thank you for your advice but i now think it is time to call the engineer in to have a look.

Tina
January 2009
if the boiler is not even trying to start it may be the
external controls.
the only to test the room stat and timer is to disconnect it at the boiler and do a continuity test
with a multy meter or link the terminals on the boiler.

b
January 2009
The boiler is set on the timer mode so it should only come on in the morning and evenings and the thermostat is set at 21 degrees and the current temp is 14 degrees(cold).

The white pin on the timer is situated in the middle as always and i have even tried it in constant mode.

The test button on the thermostat that usually works and fires up the boiler is no longer working but did a days or so ago and i have a feeling it may be related.

Tina
January 2009
is the heating set to constant and the room stat on max

b
January 2009
no, its still not working :o(

Tina
January 2009
does the heating work now

b
January 2009
Hello, i have checked the pin and that does not stay out after the hot water has been turned off so that seems to be working ok.....any more troubleshooting tips would be greatly appreciated.

Tina
January 2009
2 screws on the bottom panel undo them a bit
and lift the top panel up and off then the undo the 2
screws all the way intil the bottom panel drops down.
behind the bottom panel on the left hand side is the
diverter valve, it brass. on the end is a switch.
when a hot water tap is turned on a rod will come out
and push the switch, some times that rod stays out.
if it has push it back in. turn the electric off before you start

b
January 2009
If it is the diverter valve sticking how would i fix it.

Tina
January 2009
some times the diverter valve sticks in the hot water
position stopping the heating from working

b
January 2009
The dial is turned fully to the left and is on the heating and hot water mode

Tina
January 2009
could be stuck in hot water mode

b
January 2009

Related Questions ...

Mend boiler heating radiators
1

My radiators not heating up?

I have a 281 G/star combi boiler and have been away for 1 week and now back . Boiler is heating water fine bu... [Read more]
Mend thermostat boiler fault
1

Which model room thermostat do I need?

I have a Worcester Green Star 37cdi combi boiler. The room thermostat controller is showing an E1 fault so I ... [Read more]
Mend boiler heating temperature
2

Worcester Bosch Greenstar Ri v Beast from The East?

My boiler has been struggling to reach thermostat temperature and has now started gurgling like its boiling a ... [Read more]
Mend combi boiler central heating radiators
1

why is my combi boiler not staying fired for central heating. water fine?

my Glow worm combi has been having odd days when the central heating isn't working but then has been ok again ... [Read more]
Mend boiler thermostat heating
2

Baxi Combi 80e - Hot water Inconsistant?

I have a Baxi Combi 80e. I have an issue that the hot water doesn't run constantly when the tap is on and will... [Read more]
Mend heating thermostat combi
1

ideal combi 30 boiler heating not working on timer only override?

The heating only comes on when I override the timeclock if in timer mode the timeclock keeps the correct time ... [Read more]
Mend boiler heating thermostat
1

combi oil Worcester greenstar heatslave 12/18 switches off?

I have a internal combi oil Worcester greenstar heatslave 12/18 Its has a built programmer and Hot water t... [Read more]
Mend kick started hot
1

Boiler needs kick started by hot water for heating?

We have a Combi boiler controlled by a Hive thermostat. The scenario is that you get up in the morning and th... [Read more]
Mend britony combi se
1

Britony Combi Se?

I have a Britony Combi Se boiler with the error code 50 80 which means domestic hot water thermostat this has... [Read more]
Mend combi boiler heating thermostat
1

Baxi 105e Combi Boiler?

I have a Baxi Combi 105e which has been really great until now but has starting acting up and I think it needs... [Read more]
Mend combi boiler fault
2

Morco combi boiler fault?

My Morco combi boiler FEB-24ED shows a fault F4 (Hi Limit Thermostat Failure) how do I repair this. Tha... [Read more]
Mend boiler combi thermostat
2

How to fix my Ariston MicroGenus MFF1 23 combi boiler?

It appears that the timer does not work to turn of the boiler off when it is instructed to do so. The thermost... [Read more]
Mend boiler heating thermostat
1

Remeha Avanta Plus not not activating heating?

I have just moved in to a new property with an Avanta Plus Combi Boiler. It works fine for heating the Hot Wat... [Read more]
Mend boiler thermostat central heating
1

Ravenheat heating thermostat transmitter does not work?

My Vaillant combi boiler provides hot water but the Ravenheat transmitter type thermostat has stopped working ... [Read more]
Mend boiler heating thermostat
1

Baxi Combi HE heating does not turn off?

My boiler above is only 6 months old but now even when we turn the thermostat right down the heating does not ... [Read more]

How to mend ...

Find out how to mend just about anything howtomendit.com for free repair help, information and advice.
Mend Home Heating Systems ...