vaillant turbomax 242E hot water too hot?

[MP plumb]

the original problem was that the hot would only work with the heating on....so new diverter, and the hot wasn't HOT, so i gave a few options... but in the end, i changed the diverter and secondary heat ex. all was good but after about 3 weeks i got a call saying the hot was STEAMING hot.

the dial on the front was on 5 when i went back to the job, and at about 60 deg, so i turned it down to setting 2, to see if the temp dropped, which it did, then went up again when i turned the temp up again...so i know the dial is reading correctly.

is ther something internally i can change for the temp?

a few of the guys have said maybe they havent realised just how hot it can get since they have had a low temp for so long... but now it almost too hot to touch on number 2?!! that doesnt seem right to me.



also... on a combi, what is the max a hot water should reach?

thanks
x

 

[Billy Bob Bob]

on a combi max should be 60 degrees take the cold reading of the DHW thermistor and compare it to the values given in the mi,s or by valiant technical

 

[MP plumb]

sorry gasman, but what is mi,s?

 

[Whn1]

Is the hot flow rate as good as its always been?

 

[Billy Bob Bob]

sorry gasman, but what is mi,s?

manufacturers instructions it should give a value typically 9-14 k ohms cold,if you get varied all over the shop readings then the thermistors shot BUT​ you must check it when the boilers stone cold

 

[MP plumb]

Whn1. flow rate as normal... just the temp alot better.

gasman, i feel im out of my depth? im hopefully not gana look like a div, but i didn't change any thing but the diverter and heat ex, and they dont have any temp governs on them, so how could i of affected it, apart from making it better?

 

[Whn1]

I was thinking if it was possible that you may have got something stuck/bllocking the flow of the hw in the boiler causing it to pass through more slowly and heat up more?

 

[MP plumb]

hi, i thought id let you all know what the vaillant reply was...

it appers you may have a blockage on the primary's of the plate heat exchanger, the flow is not circulating quick enough. check the flow and return differentials (20 deg)

also, clean the operating tube copper 4mm that runs from the differential valve to the diverter as this is prone to blockage.


thanks MR.Vaillant tech guy... and thanks Whn1... you was on the right track
hope this helps more people

 

[diamondgas]

Always learning 'clairplumb' ... not the usual fault this time of year being the hot water being too hot! Good thing to get in your tool kit is a flow meter and thermometer .. IMHO! That way you can check what you've got agianst what the MI's state.

 

[MP plumb]

diamondgas, thats what i love about my job1 no one knows every thing about everything! doesnt matter how long youve been in the trade

how can it be blocked though?could it just so happen that me draining the boiler, changing parts and re pressurising made a blockage?!!

 

[diamondgas]

diamondgas, thats what i love about my job1 no one knows every thing about everything! doesnt matter how long youve been in the trade

how can it be blocked though?could it just so happen that me draining the boiler, changing parts and re pressurising made a blockage?!!

It's possible that debris in the mains has been dislodged and restricted the flow, it's possible that the iso valve hasn't fully turned back on? Who knows claireplumb YOU are not neccessarely to blame though! Just unfortunate circumstances imo