vaillant ecotec no heating just water

[jaguar66]

now you mention it i think i can remember the tutor showing us how these thermisters are tested im just struggling to remember the process.

 

[M.Joshi]

On the thermistors what does ntc mean and how do i test this I have an auto ranging test meter but im unsure what to do & do i still test this with no power on.

NTC - Negative Temperature Coefficient (Resistance decreases with increasing temperature)
PTC - Positive Temperature Coefficient (Resistance increases with increasing temperature)

Thermistor - Wikipedia, the free encyclopedia

Best to test the thermistor out of circuit i.e. with the wires/leads to the PCB removed. Otherwise you may be measuring other stray resistance.
You place your multimeter in resistance measuring mode (usually kohms) and touch the 2 multimeter probe tips either way round across the thermistor terminals.

 

[Leo21]

How can it be the thermistors if it works in test mode?

 

[jaguar66]

NTC - Negative Temperature Coefficient (Resistance decreases with increasing temperature)
PTC - Positive Temperature Coefficient (Resistance increases with increasing temperature)

Thermistor - Wikipedia, the free encyclopedia

Best to test the thermistor out of circuit i.e. with the wires/leads to the PCB removed. Otherwise you may be measuring other stray resistance.
You place your multimeter in resistance measuring mode (usually kohms) and touch the 2 multimeter probe tips either way round across the thermistor terminals.

Thanks for that I believe the customer has had a battle of wills with his wife over ownership of the switch one turns it up and the other turns it down I think that may be the problem ta..I will get back to you when ive been tommorrow.

 

[arran197]

To be honest with you mate, any combi's with no ch but hot water will most likely be an external control fault. Thermistor's rarely fail (with the exception of Ravenheats). It won't hurt to test a few when you go to the next boiler though, set your multimeter to ohms (the Omega style sign) and connect your leads to the prongs as described above. NTC you will see the resistance go down as temp rises and PTC the opposite.

 

[dancinplumba]

too much info in an open thread ????

 

[arran197]

Is this open to anyone? I thought the GSR forum was for those only registered? Not going to cause any serious issues testing a thermistor with a multimeter though I wouldn't have thought?

 

[jaguar66]

Thanks guys your help is much appreciated i will test a few.

 

[ambrosia]

check thermisters on ch side are ok also
flow turbine and diverter

its an ecotec only one thermistor/NTC
if the little radiator sign comes up then check the pump, it may no longer be strong enough to pump around the heating circuit, but enough to do the hot water

if there's no radiator sign then its not registering call for heating and could be pcb

 

[jaguar66]

Hi guys just a question
In regard to the heating control on this boiler im back tommoz to confirm the swith is fubard so if its not working at all and i remove the link between 3-4 and connect an external programmer will this overide the control on the boiler as the manual does not explain clearly enough either that or im too thick to understand it.