TURBOMAX PLUS 824E

[1FlameLift]

Hi
Ive got a problem with a Vaillant Turbomax plus 824e. The pressure from the hot tap is weak and the water temp doesnt go above 56 degrees.

The hot water heat exchanger was replaced 3 weeks ago by a friend of mine and the customer said when it was first fitted everything was all good for about a week.

Could there be a blockage in the new heat exchanger?

The flow pipe in the d/h heat exchanger is hot but the return pipe out of the exchanger isnt.

 

[bengasman]

Do you actually mean pressure, or flow weak?
Why was the hex changed?

 

[1FlameLift]

The flow rate is much weaker compared with the cold tap. The hex was changed because it was old and blocked.

 

[bengasman]

The flow rate is much weaker compared with the cold tap.

That is fine, as long as you get about 12l/min

The hex was changed because it was old and blocked.

If it was the boiler side that was blocked, it won't last and block up again. and again. and again.

 

[Agile]

You said I think that you are new to boiler repairs and I hope that means you are qualified because you seem to have little understanding of basic boiler operation and faults. Thats why posting in the CC is better as it does not embarass me by seeing it here in the view of the public.

Plate HE faults are one of the most common and so simple as no electronics are involved.

In parts of Berkshire the water is very hard and scaled secondary sides are encountered particularly when a tap has been driping. Sometimes they block completely and there is no flow at all to the hot taps.

Tony

 

[simond]

It's not going to be the DHW side of the heat exchanger in 3 weeks.

Also if it was this side the water would be excessively hot.

It sounds like the new heat exchanger has started to block on the boiler side AND the OP has no idea about boiler faultfinding.

 

[5544]

now, i am only asking this as a means of understanding what is being said,
Q, if the above is correct, how does the blocked primary side of the heat exchanger affect the water flow rate through the secondary side of the the plated heat exchanger. i could understand the secondary side blocking causing reduced flow due to hardness, but the primary? I know the primary can just as easily get sludged up due to a dirty primary but wouldn't it just cause great difficulties in transferring the heat from primary to secondary and possibly cause other problems in the process?
if the secondary was clear surely you would still get reasonable flow rate?

further discussion on this topic would be beneficial thanks.

 

[1FlameLift]

Hi Guys, Thanks for your input. I am new to Fault finding and I am ACS qualified i've just done alot of installs and not breakdowns.

I don't think the DHW heat exchanger could get blocked up again after just one week, Unless the Primary Heat Exchanger is full of sludge.

I checked the fault history on the boiler and F.22 (Dry Run) was repeated 10 times. Customer said he had a radiator that leaked.. Could of leaked for months!

Maybe the flow isn't that good because of the aqua sensor?

Also The diverter valves Actuator was faulty, it was spinning around and not moving in and out. It was open on both heating and hot water. Customer said that when he would run the hot tap the radiators would get hot but the water would be worm..

Thats all the information i have on this boiler.

Hope you can help

 

[bengasman]

...I don't think the DHW heat exchanger could get blocked up again after just one week, Unless the Primary Heat Exchanger is full of sludge.

That is the only reason I have ever seen a platehex block; sludge.

I checked the fault history on the boiler and F.22 (Dry Run) was repeated 10 times. Customer said he had a radiator that leaked.. Could of leaked for months!
Also The diverter valves Actuator was faulty, it was spinning around and not moving in and out. It was open on both heating and hot water. Customer said that when he would run the hot tap the radiators would get hot but the water would be worm..

So adding up, that makes:
Corrosion with suspect plate hex and possibly pump damage
Leak(s)
Duff diverter

Sounds like it is going to be an expensive repair.

 

[1FlameLift]

Im gonna have to just take out the DHW heat exchanger and have a look see..

I fitted a new diverter and pcb because ive been advised that if the diverter is faulty its best to change both diverter and pcb.

 

[bengasman]

...I fitted a new diverter and pcb because ive been advised that if the diverter is faulty its best to change both diverter and pcb.

You are either pulling my leg, or being taught by someone who does not know his arse from his elbow when it comes to fault finding/boiler repairs.

Just think about it.
pcb = (virtually) only electronics
diverter = (virtually) only mechanical
they are not directly linked either.

Even if you know absolutely nothing about how boilers work, basic logic should tell you that 2 items that are not directly related do not have to be replaced together unless there is specific evidence that they are BOTH faulty.[/b]

 

[1FlameLift]

The original PCB wasn't sending any power to the diverter valve. Once I replaced the PCB I noticed the diverter valve was faulty. So both needed replacing.