vailant turbo max VUW 282 E over haeating

[gbrown58]

Hi Can any one help
I have a vailant turbo max VUW 282 E which over is haeating and cutting out when in central heating mode?
I have cleaned out both the heat exchange unit and the direct hot water exchange unit (advised to do by engineer)
the system has been cleaned and flushed
Overheat stat replaced
NTC replaced
any help would be appreciated
many thanks

 

[kevplumb]

try checking the pump and or diverter valve

and make sure the cap on the aav is loose

 

[Agile]

How did you clean and flush the heat exchanger/system?

How do you know its clean and not blocked?

Did you inspect the pump impeller?

Have you set the heat output to match the property on CH ? I presume you dont live in a 10 bedroom house.

Tony

 

[gbrown58]

I cleaned the exchangers by removing from boiler and using a cleaner.(ferox ? that I was advised to use form the plumbers merchant)
there was a lot of iron oxide in the DHW exchanger but very little in the main heat exchanger.
I have not checked the pump
the aav is sound
I changed the diverter valve 12 months ago
(Have you set the heat output to match the property on CH ? I presume you dont live in a 10 bedroom house. ) with regards to the heat output the dial is set between 5 & 6
the system is running 13 radiators when on full however there is a zone valve fitted so that only down stairs and bathroom are on (5 radiators)

 

[kevplumb]

(Have you set the heat output to match the property on CH ? I presume you dont live in a 10 bedroom house. ) with regards to the heat output the dial is set between 5 & 6
the system is running 13 radiators when on full however there is a zone valve fitted so that only down stairs and bathroom are on (5 radiators)

range rating the appliance is RGI territory

not just turning the stat down

 

[gbrown58]

range rating the appliance is RGI territory ?
is this factory set? does it require regular setting?

 

[kevplumb]

it should be set on installation

if your putting to much heat in for the load the boiler is gonna turn off

28 kw boiler in 10 kw heating load out

where is the rest going

this does not affect the hw btw