Changed DV on Ravenheat 820/20 problem with DHW

[MikeG]

I have had this Ravenheat 820/20 boiler for now 8yrs from the previous house owner.

During this time I have replaced the Divert valve for the second time just 2 months ago.

The first valve the diaphram was torn and couldn't find replacement back in 1999 so paide £180 for a new divert valve,

This valve started to leak from the front so had to replace it again after 6yrs.

I was searching for a supplier and came across BES and found they sold a replacement and appeared much cheaper so without searching around I ordered knowing I had paid a lot more for it 6yrs ago....I thought the price must have come down.

I had replaced the valve 2 months ago but it is today I noticed there is a problem with the hot water supply as today we have had a nice sunny day and hence the heating has not been running.

I went to have a shower this afternoon and there was very little hot water coming thru the mixer shower, had a look at the boiler flame and it was heating the water but this heat was going into the ground floor radiator instead of the hotwater circuit.

I was wondering what could be the reason for this behaviour with new valve from BES. Could it be the pin in the valve is sticking and hence the valve is remaining open half/half.

Any advice on how to check its operation besides seeing the valve going in and out with the opening of the hot water tap?

I must admit like everyone here thinks this boiler although is of very simple simple design the components are very poorly designed compared to the likes of Valiant's.

Any advice will be appreciated.

 

[Agile]

Your have to understand that the cheaper part sold at BES is NOT a genuine manufacturer's part but a semi equivalent.

If the diaphragm assembly is moving and operating the switch but the system water is going to the radiators then the manifold section is stuck and not moving under the spring pressure to follow the diaphragm.

That implies that there is considerable dirt in your system and that has roughened the metal surface and the seals are not moving on this.

The better valves have the moving surfaces smeared with silicone grease at manufacture. I dont know about yours.

You can probably get it to move by adding a little citric acid ( about 50g ) or DS40 to the boiler ONLY with the rads isolated from the boiler and run it on DHE for 10 sec on/off cycles and that will probably clean it enough to make it work properly.

It could well be that the whole system needs cleaning. DS40 can cause radiators in poor condition to leak!

Tony

 

[MikeG]

Thanks Tony for your very detailed reply.

Yes I couldn't agree more with you that the BES DV is definetly not the original product having noticed a difference in the operation of the valve compared to the previous valve.

With reference to possible dirt in the boiler, I must mention something I left out in my question. I noticed that after replacing the valve I started hearing the water boiling up in the heat exchanger with CH or HW something I never noticed before. The boiler was always very quite during its operation.

After changing the valve I have been getting also severe water hammer when shutting the hot water taps something we have never experienced before.

I am begining to wonder whether this valve is of the wrong type altogether and that I should consider ordering the one from LPS Supplies at www.lpssupplies.com who are Ravensheat's spares suppliers. £120 +vat.

I will have to remove the valve and check its operation and will take your advice of cleaning up the boiler by isolating the radiator circuit. I was hoping if I can delay this work until after the weather gets a bit warmer.

While on this topic, I was thinking if I was going to have to spend yet another £150 on a third DV would it wise to change the boiler altogther.

The only consideration comes to mind is how much pipe re-fitting will be required any advice will be greatly appreciated on this. I have 10 radiators and a mixer shower unit in the house. Any advice on a Valiant boiler of a similar size as the 820/20 would be useful.

MG

 

[HarrogateGas]

It has nothing at all to do with dirt.......i fitted a cheap BES divertor valve to my brothers boiler as the house was sold so a cheap fix was all that was required. i got a div valve from BES (£25 ring a bell). The new part passed to heating from new. I would also like to pointy out that mys bro's system was flushed (jetflushed) and ihibited 3 months prior.

They are cheap for a reason and that is they are no good and not up to the job

 

[kevplumb]

It has nothing at all to do with dirt.

it must be the great font of all knowledge says so

 

[Agile]

If you want to take the valve out then you can use warm citric acid solution directly in the manifold section or even remove the inner part and clean it.

I would not have expected that the new valve is responsible for any changes in operation of your boiler but it may be showing up deficiences in the boiler itself such as dirt and blockages. However HG has had a bad experience with one although thats the first case I have heard of.

Your boiler is 24 kW which is the basic boiler size but most owners would choose a 30 kW model as a replacement to improve the DHW output.

Since a condensing boiler needs a condensate drain as well then it would be best to to choose what you want and then do whatever is necessary to the pipework to get it to fit.

Tony

 

[ChrisR]

I bought one DV from BES for a look. Oddly they specify a lot more different models than seem to be necessary.
Though it's obviouslly not a Giannoni, it looks much the same. A bit like the "MUT" ones. What do you think is less good about them, HarrogateG?

I wouldn't get excited about the parts other boiler manufacturers use , MikeG, Worcester and Vaillant also use/have used Giannoni valves, same make as your Ravenheat.

 

[MikeG]

Yes ChrisR, I take your point that all the manufacturers do not make their own parts. I must admit I didn't find it any different to the original one but I am no longer an expert boiler engineer. I used to be one 15yrs ago. I had worked mainly on the Valiant combi boilers of those days.

In fact the DV supplied by BES that I received had the oulet connections on the opposite so I undid the 10 or so screws and turned the assembly round to line up on the correct side.

I will have to remove the valve and inspect the operation to see how the valve is closing by pushing it manually. I think there is something wrong with this valve as I remember the day I had fitted the valve when the hot water was in use I had noticed the first radiator being warm although the CH was not switched on.

This will have to wait until next weekend. I will report back my findings so that others can know.

MG

 

[gas4you]

'Buy cheap pay twice' ring any bells

 

[MikeG]

'Buy cheap pay twice' ring any bells

I today took out the valve to inspect what was going on and I found that the spring/plastic assembly which fitted to the front facing inlet has broken inside.

I could earlier hear bits inside the boiler with the heating running now I know what was making this noise and I have a feeling this blockage has also damaged my heat exchanger which has been dripping.

I opened the fan assembly and removed the top but could not see where the drip is coming from.

I found the box in which the valve was supplied by BES and it has a label which indicates this valve which is supplied by BANICO part # DVS-F2 is for the RSF820/20, RSF820/20T, CF10/20 and CF10/25

I checked the name plate in my boiler and found my boiler is actually a RSF20/20T for this model they do another valve DVS-F1.

So looks like I have been supplied the wrong valve altogether!

 

[Gasguru]

Stop wasting your time and buy the genuine part. The sooner people stop buying cheap poor quality Banico parts the quicker they will go out of business. They don't do installers any favours or BES which is rapidly loosing my business by selling this crap.

BES are going the same way as Antares - cheap copies not worth fitting and they don't seam to care about it.

 

[MikeG]

Yes, Gasguru I couldn't agree more with you. I should have searched again for the genuine part instead of ordering the BES part knowing the previous valve I had ordered was £180.

I thought the price must have come down over the last 6yrs.

I will have to get back in touch with Ravensheat to find out the correct part no before I order the new part this time round.

I noted a post where someone else has also suffered a leak, I also has the exact leak from the middle part of the valve and there is no way to fix this problem this leak happened after 6yrs of use which I think is not too bad.

When I took out the valve I had a quick look as to how the valve closes and opens inside, it appeared to be working fine but as I have disposed the original old valve I cannot compare.

I just hope I don't have a leak in my heat exchanger although I know there is a drip coming from it.

Heat exchanger is £250 plus £150 for the divert valve that is £400, I will most definetly have to get a new boiler.

For now I just re-fitted the valve to get through the cold spell.

Has anyone replaced the RSF20/20T boiler with another make without having to re-route the inlet pipes?

 

[ollski]

Just needed to refurb the original valve with the relevant kit(s), nothing goes wrong with the main brass lump of the valve.

 

[ChrisR]

I found that the spring/plastic assembly which fitted to the front facing inlet has broken inside.

Not sure I've ever seen one with plastic parts inside. You don't mean the "rubber" diaphragm do you?
I don't know of any kits which replace the parts in the diverter section other than the small gland seals.

It's pretty normal to have to rotate the end with the microswitch on, to suit a boiler, which doesn't cause any problems.

Which part was broken?

pic

 

[MikeG]

I found that the spring/plastic assembly which fitted to the front facing inlet has broken inside.

Not sure I've ever seen one with plastic parts inside. You don't mean the "rubber" diaphragm do you?
I don't know of any kits which replace the parts in the diverter section other than the small gland seals.

It's pretty normal to have to rotate the end with the microswitch on, to suit a boiler, which doesn't cause any problems.

Which part was broken?

pic

The part that is broken is inside the inlet which connects to the pump 3/4 which is the front facing inlet when looking from the front with the microswitches at the back.

I think in the original valve there is a brass ring which has a 3 point star like circlip which holds the spring inside, the replacement type this is made of plastic.

I have found to my dismay the valve that was supplied was the wrong one which I beleive has caused flow rate for the DHW and CH to be restricted hence this has overheated the heat exchanger. I have a leak which is coming from the heat exchanger.

I need the 0008VAL0310/0 for my Ravenheat RSF20/20ET I was supplied with the 5012049.