Baxi 105e with bristan mixer shower not igniting boiler

[Fizza]

Morning all this problem has just started we had a prob with low pressure on the street I contacted united unlitities and we had found they had fitted a pressure reducing valve at the bottom of the hill due to new housing estate built they increased the pressure then it worked fine

When the shower is turned on it doesn't always ignite the boiler but if you turn the hot tap on in the bathroom adjacent it ignites the boiler and the kids can take a shower without complaining lol . I have read it could be a cartridge issue pls can anyone advice

Thanks fizza

 

[terryplumb]

is the shower thermostatic or a basic mixer ? first thing i would check is the filters where pipework enters the mixer valve. given that uu have been doing work on mains ,it's possible that sediment is blocking the filters .have you noticed a drop in the showers performance when it is running ? I assume you turn TAP off once shower starts.

 

[Fizza]

Thank you for your reply it is a thermostatic shower the pressure seems fine when running but goes cold and if you turn a tap in the bathroom it starts to go hot again i only turn the tap on so it ignites the combi again and the kids have heat again lol we have no probs with any other taps calling for hot water thanks

 

[terryplumb]

do you have to turn tap on more than once while kids shower or once is enough and then stays OK for duration of showering ? and is your hot water at an excessively high temperature, for instance if you run a hot tap for 2 minutes then put hand under can you keep your hand under for 1 minute or does it become too uncomfortable ,indicating temp is too hot from boiler.

 

[picasso]

Could be a faulty venturi in the cold water section of the boiler.

 

[Fizza]

Hi there I only need to turn the tap on once if I run a hot tap I couldn't keep my hand under for one min it would be to hot

Thanks

 

[terryplumb]

think you could try lowering the domestic hot water temperature on the boiler , the dial marked tap symbol .I don't think your thermostatic valve is in best condition and is struggling to cope with excessive temperatures on start up and then stabilises after tap runs off. your boiler has a heat store facility within it. bear in mind that the temperature of the cold water coming into your property is much warmer now than it was in colder weather ,this has a direct effect on the hot water temperature that the boiler delivers .so your current shower problem would not have been there in colder weather .obviously I am not there so its a theory and I may be totally wrong ,but at least it will rule out a possibility before you have to start spending money replacing valves etc.regards terry

 

[gas112]

Picasso has hit it on the button
https://www.diynot.com/diy/threads/baxi105he-with-thermostatic-shower-problems.385786/#post-2961366

 

[Fizza]

Thanks all I will have a go later

 

[Fizza]

Evening all I reduced the temp on the boiler this morning it worked fine tried it again this evening and it didn't ignite the boiler until I told the hot tap on. Then was fine I watched the boiler whilst shower on after 20secs the flame went out the started again any more suggestions pls I can take cartridge out at the weekend and clear filters etc thanks

 

[terryplumb]

worth the try,but it looks like the boiler is not working as it should ,as Picasso advised earlier , and gas112 did earlier today. the venturi needs checking /replacing in the boiler.

 

[Fizza]

Ok thanks I will have a look

 

[Fizza]

Hi all i got a new venturi ass got the boiler cover off on the diagram is it the 23mm nut thats hard to get to lol where the venturi sits

 

[Fizza]

 

[gas112]

yep use a 24mm ring spanner just turn cold off no need to drain it then get your finger or lump of blue tac into hole and pull out any broken bits left in there