Hot radiators when turn on and off hot water for a few times

[ptlli]

Please let me know why the radiators near the boiler (valliant Turbo Max 282E) get hot when I turn the hot water on and off for a few times. When I feel the heating return pipe after turning on the hot water for a while, it is only warn,but after turning the hot water tap pipe off, the pipe is very very hot. I only notice this about a month ago. The boiler is 5 years only old.
Thank you
Pat

 

[weargas]

it's still the diverter valve. The diagnosis hasn't changed since your other post.

 

[ptlli]

it's still the diverter valve. The diagnosis hasn't changed since your other post.

Can I just change the diaphragm? Can the DV be repaired?

 

[weargas]

On the turbomax you can repair the diverter valve with a dv service kit or just replace the dhw diaphragm. I'm sure in your first post you specified that your boiler was a turbomax plus which would make some of the advice given not viable for the turbomax.

 

[ptlli]

On the turbomax you can repair the diverter valve with a dv service kit or just replace the dhw diaphragm. I'm sure in your first post you specified that your boiler was a turbomax plus which would make some of the advice given not viable for the turbomax.

Thank you very much for your advise.
Pat

 

[ChrisR]

Nah, he did say Vaillant TURBOmax VUW 282E !
The whole valve is something like £129 + vat, and the service kit (which has much more than just a diaphragm) about £29 + vat. There's a small microswitch on the right side of the DV as you look at it. If the switch looks llike it is being operated really well as soon as you turn the HW on, the problem probably is not just the diaphragm. there are some thin rubbers in the diverting part of the valve which get displaced.
If you DO just need to change the diaphragm, change the microswitch too - later ones are better.

Taking the diverter valve out isn't particularly easy your first time, and neither is taking it to bits to replace all the rubbers inside. Then you're quite likely to get leaks when you put the DV back in. And there's a v small screw which can shear off easily - wrecking the DV!

The earlier versions of the valve were particularly troublesome. Though later ones seem better I don't know if the unreliable bits are changed by installing the full service kit. Do you know, Weargas?

 

[weargas]

Nah, he did say Vaillant TURBOmax VUW 282E !

But the first post on his other thread was edited on the same day as this one was posted.


I almost never change the full diverter valve unless it looks like a leak has made screws impossible to get out. The diverter valve service kit contains dhw diaphragm, all moving parts, o-rings, fibre washers and the microswitch. You even get most of the screws and a little pack of silicone grease. That daft flimsy plastic arm is still the same as it ever was. After you've done a couple of valves you can get it down to a 3/4 hour job.

 

[ChrisR]

Sure - and you can winkle the daft flimsy plastic arm out sideways without dismantling.

Do you know owt about the changes they made to make the valve (a bit ) more reliable?

I'm thinking that though a new DV costs more, swapping is quicker than stripping, so if the end result is better then the extra is perhaps worth it.

 

[weargas]

The only difference that I know of on the diverter valve is that the o-rings on either side of the dry section (where the placky arm goes) have been doubled up. A modified plastic bush holding them in allows 2 o-rings to sit on top of each other.

I tend to keep my purchase cost of spares down to stay below the dreaded limit. It also benefits the customer moneywise.

 

[ptlli]

The only difference that I know of on the diverter valve is that the o-rings on either side of the dry section (where the placky arm goes) have been doubled up. A modified plastic bush holding them in allows 2 o-rings to sit on top of each other.

I tend to keep my purchase cost of spares down to stay below the dreaded limit. It also benefits the customer moneywise.

Any idea where I can get the diverter valve service kit. I just bought a diaphragm its come with 7 screws and a spindle. Also I look at the silicone grease, it costs over £10 for just 85g. Can I just use ordinery grease on the spindle.
Pat