Vaillant ecotec Plus 428

[jaydebruyne]

It's not going above 42 degrees. Burners on. Have checked thermostat and it's working fine. It ramps up every now and temp goes to 50 odd and then ramps straight back down and temp goes back to 42...????

 

[townfanjon]

Is this on ho****er or heating or both

 

[townfanjon]

Hot water

 

[jaydebruyne]

Hot water

Both mate.. have tried with just heating, just hot water and both

 

[Last Plumber]

428 is a regular boiler
but any how, check thermistor value and see if it can be moved to gas safe only area

 

[jaydebruyne]

Can this thread please be moved to gsr only forum pppppplease???

 

[townfanjon]

Your in bother now Jay

 

[jaydebruyne]

Your in bother now Jay

Lol tell me about it!!!

 

[bert large]

Had this before on this exact boiler years ago but can't remember for the life of me how I overcame it.
Think it was something to do with insufficient difference between flow & return temps. These Vaillants can be too clever for their own good sometimes.

Try changing output (D0) from Auto to about 18Kw or 20Kw

 

[gassafe]

Sounds like it's been adjusted to low output or something's if possible... or maybe a sludged is hex.?

 

[jaydebruyne]

Sounds like it's been adjusted to low output or something's if possible... or maybe a sludged is hex.?

I thought about the low output thing but the owners wouldn't have a clue how to do it.

Sludged is hex???

 

[gassafe]

Yeah the vaillants are complicated, any chance the max flow was adjusted to 50 by mistake?

I meant sludge in hex as Iv had them kettle a lot with that silly spiral hex, but the flow went up 70 & then shut down & ticked over on minimum from memory...

 

[jaydebruyne]

Yeah the vaillants are complicated, any chance the max flow was adjusted to 50 by mistake?

I meant sludge in hex as Iv had them kettle a lot with that silly spiral hex, but the flow went up 70 & then shut down & ticked over on minimum from memory...

Ohhh sorry.. forgot hex is short for heat exchanger..

How do you adjust max flow temp? Also, why would it ramp up to 65 then drop back down to 42? It does this every 10-15 mins. The burner is on continuously too. Never goes out. I'm gonna bring a ntc sensor with me next week in case it's that but I don't think it is.

 

[Dotty]

Moved off open forum.

Thighs will be slapped tomorrow.

 

[Dotty]

Moved off open forum.

Thighs will be slapped tomorrow.

 

[PhoenixServices]

Most likely heat exchanger blocked. Classic symptoms and prone to blocking. Although had one which was blocked and also been turned down to minimum output by manufacturer.

 

[MatthewHurt]

If your Delta T is too low or too high then the boiler will go into a blocking mode. Check the S codes when.the boiler is in operation (they are all in the book) any code ending in 8 is a blocking code.
Is the pump wired to the boiler of wired externally? If it's external this can cause damage to the Heat exchanger as you effectively have no pump overrun.

You can view the Flow & Return temperatures via the D codes (D40 / D41)

 

[Rabbitman]

The heat exchanger on the 4 series is not as bad for blocking as on the 6/8 series although anything is possible, as for your original problem i suspect that when the boiler is on and struggling to reach over 42* the status code would be S53/54 and would be down to the temperature rise when first starting up........ Ie so many degrees in so many seconds etc etc, if it doesn't see the correct rise it will drop its power too a lower output for approximately 20mins before re trying, and so on and so on, this is can also be accompanied after 5 failed attempts with a corresponding F codes but not always ...... And as previously mentioned is down to circulation wether it be appliance or system

 

[jaydebruyne]

The heat exchanger on the 4 series is not as bad for blocking as on the 6/8 series although anything is possible, as for your original problem i suspect that when the boiler is on and struggling to reach over 42* the status code would be S53/54 and would be down to the temperature rise when first starting up........ Ie so many degrees in so many seconds etc etc, if it doesn't see the correct rise it will drop its power too a lower output for approximately 20mins before re trying, and so on and so on, this is can also be accompanied after 5 failed attempts with a corresponding F codes but not always ...... And as previously mentioned is down to circulation wether it be appliance or system

There aren't any status codes.. the boiler itself shows no errors. I put in an alpha2L pump and set it to the highest variable flow - think I'll put it to set flow and see if that changes anything. Must be circulation though as before the upper rads were getting up to temp but downstairs rads weren't. Checked pump which was weak. They go through a pump every couple years. Also tenant has to constantly bleed towel rad in top floor bathroom.

 

[Rabbitman]

There are always status codes?????? Not visable without looking but there all the same and without them you wouldn't know what the boiler was doing

 

[jaydebruyne]

There are always status codes?????? Not visable without looking but there all the same and without them you wouldn't know what the boiler was doing

On the digital display it literally just reads the temp :/

 

[Rabbitman]

You've got to press the i button........ Then it will show 5.(then a number) that's what tell you what the boiler is thinking so too speak

 

[jaydebruyne]

You've got to press the i button........ Then it will show 5.(then a number) that's what tell you what the boiler is thinking so too speak

Ohh - sorry. Not used to Vaillants!!! Cheers Rabbitman! Are the meaning of such codes in the manual? As obv can't call them as will be at custards in an hour

 

[Last Plumber]

https://www.google.co.uk/url?sa=t&r...17.pdf&usg=AFQjCNFRwfHldHxGNsA_0Y1weavgiLdsCA

 

[Rabbitman]

They will give you a basic description as to what each one means

 

[bert large]

I'll have a fiver on S 98.

 

[jaydebruyne]

Put the pump to set flow and all was well so yes, circulation!! Thanks for all your help guys, very much appreciated!!!