Faulty diverter valve on performa 28? An odd question....

[Brigadier]

Hello All

Bathroom rad warms up while shower is in use - I am lead to believe that a faulty DV is a likely problem.
Which leads me to puzzlement.
Presumably, no water is actively being pumped around the CH circuit, while the shower is on, but the CH is off?
The CH pressure is not rising or falling, so presumably, there is no net inflow / outflow of water from the HW side to the CH side?
So, how exactly is the CH water getting warmed up? And how is that warmed water getting to the rad?
Could I actually be showering in a dilute solution of what is in my rads?

 

[sooey]

I'm guessing you've got a combi with a mixer shower.
Guessing because you've given no useful information whatsoever on what type of system or shower you've got.

Apart from the thread title of course.

 

[JohnArnoldBrown]

You might want to take a look at my thread here:
//www.diynot.com/forums/plumbing/faulty-diverter-valve-on-potterton-gold-combi-he28.406763/

You could have a similar situation.


On the other hand, I could be suffering from "When all you have is a hammer, everything looks like a nail" syndrome.

 

[Brigadier]

I'm guessing you've got a combi with a mixer shower.
Guessing because you've given no useful information whatsoever on what type of system or shower you've got.

Apart from the thread title of course.

Apologies - as it is a DIY website, one ought to expect non-experts to ask for advice, and therefore not ask all the right questions / give all of the right info, off the bat.

I believe that it is a thermostatic mixer shower.

Yes - it is a combi.

I do not know what you mean by "type of system".

 

[Brigadier]

You might want to take a look at my thread here:
//www.diynot.com/forums/plumbing/faulty-diverter-valve-on-potterton-gold-combi-he28.406763/

You could have a similar situation.


On the other hand, I could be suffering from "When all you have is a hammer, everything looks like a nail" syndrome.

Already read it John, but thanks anyway

More (once Sooey has got all of the required info) curious as to what water is going where - heat is somehow getting to the rad, and it seems too quick to be conduction through a stationary liquid.

 

[Phill Peck]

A working diverter valve will in hot water only pass heat from the main heat exchanger to the plate to plate heat exchanger. Which transfers the heat to the incoming main water so you get hot water

When it starts to fail some of the wart will go down the htg circuit rather than passing through the plate.

 

[Brigadier]

A working diverter valve will in hot water only pass heat from the main heat exchanger to the plate to plate heat exchanger. Which transfers the heat to the incoming main water so you get hot water

When it starts to fail some of the wart will go down the htg circuit rather than passing through the plate.

Thanks GS,

so (given that the CH pressure is not rising inexorably, and certainly not tripping the PRV), I take it that some CH water is leaking back into the HW system somewhere?

 

[JohnArnoldBrown]

Could I actually be showering in a dilute solution of what is in my rads?

I think that the fact that you ask this question indicates that you don't understand how the boiler works. The same (sealed system) water is used to indirectly heat both the DHW and the CH. The same pump is used to push the sealed system water through the CH heat exchanger or the DHW heat exchanger. So you remark about a stationary liquid is a red herring.
If your diverter is faulty, or you have the problem I had, then the pump will push the sealed system water throung the rads at the same time as it pushes it through the DHX HE. Take a look at the digram of the boiler(if you can find it) and you'll see what I mean.
Here's a link to the manual for mine(or similar version, mine not an A)
Take a look at page 9 to see how it all works.


However, I'm a firmware programmer, not a plumber. A proper plumber will probably explain things better.http://www.potterton.co.uk/docs/Pot_gold_Combi18HEA_instal_sept_10p.pdf

 

[Phill Peck]

No

The water that comes out of your taps is not in direct contact with the hug water.

The water within the htg system and boiler is the same that heats the rads and heats the hot water.

The plate to plate (or secondary) heat exchanger has a series of channels one passing the heat from the boiler and the next passing water from the cold main and so on usually around 12 plates.

The reason your rad is getting hot is because the diverter valve isn't closing the htg port completely. Resulting in a small amout of the heat that should be being passed through the plate heat exchanger "passing" the washer and going into the radiator circuit.

When you work on these things every day they are quite simple. If you don't they are not.

It is a common fault and not major. So you have your boiler serviced? Or have a local engineer you use?
A pro would diagnose and repair very easily.
Don't take offence but given your understanding of how a combi boiler works, I would recommend you take this on yourself

 

[Brigadier]

No offence taken - me and water-based diy do not mix!
Just curious.

 

[JohnArnoldBrown]

Sorry, left the link out. Post now edited to include URL.

John