baxi duo tec

[desrob]

when in ch mode the boiler will fire on full rate for 30 seconds then go out for say a minute then fire again..it does this constantly,dhw is ok.as any body came across this before with this model,inlet gas pressure fine.

 

[mickie]

does the burner modulate? whats the flow temp like compaired to the return? is the return filter blocked?

 

[desrob]

does the burner modulate? whats the flow temp like compaired to the return? is the return filter blocked?

what return filter matey..

 

[Billy Bob Bob]

its fitted to the return iso valve also check fga settings

 

[desrob]

its fitted to the return iso valve also check fga settings

how do i access it,can i isolate then remove or is it a drain down,nothing in mi.....will do regarding fga...ta

 

[Billy Bob Bob]

turn off RH return side iso if it has a built in loop crack the nut bolted to the iso and bleed into a bowl then remove the nut filters behind it if theres no built in loop it will be a silver cap

 

[desrob]

turn off RH return side iso if it has a built in loop crack the nut bolted to the iso and bleed into a bowl then remove the nut filters behind it if theres no built in loop it will be a silver cap

i'll have a look tommorrow ta...on a different boiler fitting a worcester junior i 28kw,it came with a low nox chip, whats the benefits with lowering nox levels if any...?

 

[Billy Bob Bob]

i'll have a look tommorrow ta...on a different boiler fitting a worcester junior i 28kw,it came with a low nox chip, whats the benefits with lowering nox levels if any...?

less harmful pocs into the environment

 

[desrob]

less harmful pocs into the environment

why the choice ,why not fitted as standard,..strange.

 

[Billy Bob Bob]

not sure dont fit worcesters just fix them when they die,leak,blow up etc

 

[desrob]

not sure dont fit worcesters just fix them when they die,leak,blow up etc

i went back to this boiler and gas was fine co% 8.7 all good,the boiler when first knocked on runs fine until temp is reached ,then it just cycles constantly,down stairs is in 15mm on flow and return, upstairs is in 8mm and on all rads the flow is red hot and the return is cool,could this be due to a blockage on the main return pipework,and could the ch ntc be faulty causing these symptoms

 

[Billy Bob Bob]

did you clean the filter? thermister does not point to this

 

[desrob]

did you clean the filter? thermister does not point to this

yes filter ok

 

[Billy Bob Bob]

has it got a external room stat?

 

[desrob]

has it got a external room stat?

yes rf stat baxi's own

 

[Billy Bob Bob]

i would try bypassing this for testing reasons,also take the resistance (cold) of the thermister but i dont think its this its coming back to a sticking dv,blocked return or pump issue the dv,s on these you can remove the bush and spindle,clean them, grease up with silicone grease and refit

 

[desrob]

i would try bypassing this for testing reasons,also take the resistance (cold) of the thermister but i dont think its this its coming back to a sticking dv,blocked return or pump issue the dv,s on these you can remove the bush and spindle,clean them, grease up with silicone grease and refit

pump seems fine,i do think it could be a blockage,is it common for diverter to stick, and why would every thing appear to be ok until temp is reached,can ntc fail at set temp and work again in a time period of 10 seconds

 

[cdodds2004]

low nox kit basically restricts the boiler to 12kw in CH mode, so only fit if suitable for property, there is a write up with it, have a quick read explains it all

 

[Billy Bob Bob]

pump seems fine,i do think it could be a blockage,is it common for diverter to stick, and why would every thing appear to be ok until temp is reached,can ntc fail at set temp and work again in a time period of 10 seconds

its not that common for the dv,s unless the systems dirty to stick not had a thermister fail in this way but worth recording its resistance,i assume you have checked custards not knocked a iso off by mistake

 

[desrob]

its not that common for the dv,s unless the systems dirty to stick not had a thermister fail in this way but worth recording its resistance,i assume you have checked custards not knocked a iso off by mistake

yeah mate,i don't assume or take anything for granted any more,i'll let you know how it progresses

 

[Billy Bob Bob]

no probs its only a boiler we can crack it

 

[desrob]

no probs its only a boiler we can crack it

by the way this is a combi 40he....been back today and as you put it i still hav'nt cracked it,when the boiler as reached temp rather than modulate down the fan stops and the gas stops,boiler goes out,ntc ok,co2% ok on max and min,flow and return on boiler ok,rads upstairs all the flows are hot and all the returns are cool

 

[Billy Bob Bob]

i would be looking at the pump now worth taking it out and checking the impeller

 

[desrob]

i would be looking at the pump now worth taking it out and checking the impeller

i did ,it was ok,i have arranged a sservice as it's not had one since install

 

[desrob]

got a phone call this morning, the boiler will not work,code e119 low system pressure,the gauge is showing above 1 bar,obvious a faulty gauge,got me thinking that the system is dirty and has blockages