Baxi 105E, HW works but no CH

[wilsoff]

i removed the boiler when i bought the house 6 month ago after totally rebuilding the house ( feels like i have totally rebuilt) i have moved the boiler and had refitted by a friend (who is now working away). When i first tried to power the boiler up i was getting a flashing light on 60 degrees, after reading a post on the internet i ordered a diaphram kit for the front valve, i also got a new automatic air vent as this looked slightly corroded. i fitted both parts but old parts appeared ok. The fault still showed i then noticed that the pin on the rear valve was stuck open and actuating the microswitch. i pushed the pin down with a screw driver and it went fairly easy. Now i have hot water working but no central heating. But whilst i have the HW tap on the radiators warm up, but CH light doesn't light up.

With the boiler turned on CH and HW i can turn the CH stat to full and still no light or anything. the external stat is looped out. i am not sure as to how the diverter valve should work. Could some explain what valves should open with HW and what valves open with CH.

At present both valves open when i open the HW tap and the burner lights ok and also the pump runs. i am guessing the pump running is a fault. The HW led light but i have never seen the CH led lite. Is this boiler worth trying to fix. It looks in nearly new condition.

 

[adlplumbing]

possibly programmer not issuing a demand

 

[wilsoff]

programmer is looped out at the terminal board on the boiler

 

[Blooflame]

The pin on the top is the flow switch which makes the micro switch and indicates the pump is running for Central heating. Things to check-: Ensure the pin is not bent; check the diaphragm (note which way round it is, be ready for springs in there). After you lift that out, get the skinniest screw driver, really small, thin philips is perfect and jab hard downwards into a small hole that is below the diaphragm. You're trying to break solid sludge that may have formed there - it's quite common. Oh! before ALL that, check the pump works!!

 

[wilsoff]

Both pin move freely and operate switches. What should operate once the ch dial is rotated to full? Does the PCB open a valve or solinoid of any sort?

 

[onlyfitidealboilers]

The pin on the top is the flow switch which makes the micro switch and indicates the pump is running for Central heating. Things to check-: Ensure the pin is not bent; check the diaphragm (note which way round it is, be ready for springs in there). After you lift that out, get the skinniest screw driver, really small, thin philips is perfect and jab hard downwards into a small hole that is below the diaphragm. You're trying to break solid sludge that may have formed there - it's quite common. Oh! before ALL that, check the pump works!!

he has told us hot water works. most likely the diverter vlv/motor

 

[wilsoff]

onlyfitidealboilers, if the motor was at fault would the CH LED light up. Just thinking if the PCB is telling the motor to work would it also tell the LED to light up. Or does the motor tell the LED to light up.

 

[Agile]

Is this an "instant" model boiler?

 

[Blooflame]

onlyfitidealboilers, if the motor was at fault would the CH LED light up. Just thinking if the PCB is telling the motor to work would it also tell the LED to light up. Or does the motor tell the LED to light up.

Well yes...and I've explained why the CH may not be working, so what's your point?

 

[Blooflame]

sorry mate that message is for onlyfitIdealboilers

 

[Blooflame]

The pin on the top is the flow switch which makes the micro switch and indicates the pump is running for Central heating. Things to check-: Ensure the pin is not bent; check the diaphragm (note which way round it is, be ready for springs in there). After you lift that out, get the skinniest screw driver, really small, thin philips is perfect and jab hard downwards into a small hole that is below the diaphragm. You're trying to break solid sludge that may have formed there - it's quite common. Oh! before ALL that, check the pump works!!

he has told us hot water works. most likely the diverter vlv/motor

As I wrongly txted to wilsoff, I've explained why the CH may not be working..so can't see what your point is?