vaillant 824 plus cold water

[Chris_TT]

hi have vaillant 824 turbomax plus with hot/warm/cold water from tap.
Water temp changes when running tap in bath and sink.

 

[chrishutt]

Sludged up secondary heat exchanger? It's quite easy to disconnect HW heat exchanger to have a look inside.

 

[Chris_TT]

Sludged up secondary heat exchanger? It's quite easy to disconnect HW heat exchanger to have a look inside.

Is that a common fault chrishutt ?
Would there be sludge in a 2.5-3yr old whole new central heating ?
Bled one rad to check water colour (clear) but smell of cabbage/sulphur ?

 

[chrishutt]

You wouldn't expect to find much sludge in a system less then 5 years old, but it does depend very much on the quality of the installation. For example if the system was not flushed out properly there could be fairly rapid corrosion as a result of soldering fluxes.

There are other possible causes of poor HW performance, but you need to look at the manual and the various status, diagnostic and fault codes to understand what's happening. Check the HW temperature at the boiler outlet pipe as well as at the taps - the problem might be external to the boiler.

 

[ChrisR]

Also the diverter valves on those often leak very soon from new. Turn HW on, and see if Ch flow pipe(furthest left) gets hotter.

 

[Chris_TT]

You wouldn't expect to find much sludge in a system less then 5 years old, but it does depend very much on the quality of the installation. For example if the system was not flushed out properly there could be fairly rapid corrosion as a result of soldering fluxes.

What am i looking for ?

It's quite easy to disconnect HW heat exchanger to have a look inside.

Ok its off , black coating on top inlet/oulet ( x100 inhibitor ? ) nothing obivous on bottom 2 inlet/outlet .

There are other possible causes of poor HW performance, but you need to look at the manual and the various status, diagnostic and fault codes to understand what's happening. Check the HW temperature at the boiler outlet pipe as well as at the taps - the problem might be external to the boiler..

No fault codes showing. Will check temps .

Also the diverter valves on those often leak very soon from new. Turn HW on, and see if Ch flow pipe(furthest left) gets hotter..

Tested with a clip one pipe thermometer (how much temp diff and how quickly?) looks ok will check again with a digital one.

 

[ChrisR]

(how much temp diff and how quickly?

Dramatic and immediate.

There are recent threads on cleaning secondary heat exchangers, here. Some kettle descalers are citric acid, which will help.

black coating on top inlet/oulet ( x100 inhibitor ? )

No, the lack of it. It's oxide of radiator.

 

[Chris_TT]

Replaced HW heat exchanger , temp on lcd changes between 46-61c and water warm to hot with tap half open . Tap open full hot water pressure changes?(minor spurts/bursts about 1 per sec ? ) seen leaving tap.

Hot water flow rate tap fully open 1 litre in 6/7secs

any more suggestions ?

 

[ChrisR]

Temp sensor(s).
Also check at meter that it's using the right amount of gas. A corgi could check what the gas valve is doing, & the temp /flow of the water.

 

[Chris_TT]

Temp sensor(s). ......

NTC1 reads 2660 ohms at 25.5C will check NTC11 & NTC111 tommro

How many ohms at what temp is ok ?

 

[Chris_TT]

Temp sensor(s).
Also check at meter that it's using the right amount of gas. A corgi could check what the gas valve is doing, & the temp /flow of the water.

A corgi called to check gas valve 10-7mb when ' modulating' ? wants to replace parts until fixed starting with pcb,pump etc

Sounds expensive second opinion needed ? Other corgis called not interested when told vailliant 824 say to call vaillant out ?

Is there a max charge to fix fault by vaillant ? Any vaillant engineers here ?

 

[ollski]

Why not use the diagnostic mode on the boiler, it will tell you which component is faulty. I would use it to check the air pressure switch isn't dropping out in the middle of a hot water demand. If you don't have instructions I can talk you through.

 

[ChrisR]

How many ohms at what temp is ok ?

New one here is 2050 at room/finger temp and 400 at 90 ish.

There's another thread here with more info.

Here: //www.diynot.com/forums/viewtopic.php?t=44579&highlight=vaillant

 

[Chris_TT]

Why not use the diagnostic mode on the boiler, it will tell you which component is faulty. I would use it to check the air pressure switch isn't dropping out in the middle of a hot water demand. If you don't have instructions I can talk you through.

pressed buttons i and + into diagnostics d24 = 0 . When hot water on d24 = 1 . Water luke warm/cold goes hot and back again.

Is that the aps test ok ?

 

[ollski]

if it stayed on 1 all the time then yes. try d22 and d35