Ravenheat 820/20 DHW probs

[ROSSEDINBURGH]

Hi y'all,

my Ravenheat 820/20T combi has developed a problem reported by others here - no hot water until CH is turned on. The advice seems to be to "check the pin is making the switch" on the diverter valve but I can't see any moving part to work manually - can anyone explain what to do please?

I'm not sure whether to call a plumber or a gynaecologist, not very accessable

I see the HW or CH sensors could be the culprit, would you tell me how to check these out too please?

Cheers,

Ross

 

[Agile]

Are you or the boiler in Gambia?

The diverter is very inconveniently situated at the back and facing backwards. You might be able to see the pin from underneath but the switch cover will probably be in the way. I would use my inspection mirror from the front.

Where are these sensors you want to test?

Tony

 

[gas4you]

It will be the diaphragm or DV stuck.

PITA to do, so expect quite a bill of around £300 or so if the DV needs replacing

 

[ROSSEDINBURGH]

Hi guys,

thanks for the replies. Both the boiler and I are in Sunny Edinburgh - the part of the joining up form where we state out country wasn't offering a drop down list and I got bored scrolling by the time I got to Gambia, so Gambia it is.

I'll have a look for the pin when I get home - thanks for locating it for me. I've only got the use of one arm so won't be tackling the DV myself. I've found the sensors in the book, they're at the front so I'll probably get them off OK, thanks. I presume the CH & DHW sensors can't be tested, rather they're replaced to see if it fixes the problem, is that right?

At £300 I'd probably replace it as they don't seem to have a great reputation and it was definitely built for a price - £450 about 9 years ago. I hear good things of Vaillant so would probably go that way if I have to, unless I hear differently here.

Cheers,

Ross

 

[Agile]

I used to replace the diaphragms on that model at our standard local price of £106 but its some while since I was asked to do one and now I might well charge rather more, perhaps £156 in view of the difficulties and scraped knuckles involved.

They are getting a bit long in the tooth and rather due for replacement.

They need servicing every year as the constantly turning fan draws dirt in.

Apart from that they are really a very reliable boiler.

If they are not serviced the combustion chamber cover becomes virtually glued on as the seals stick on both sides. If I do get one off I put silicone grease on them to make it easier next time!

Tony

 

[ROSSEDINBURGH]

Thanks Tony,

with the benefit of hindsight, I should really have mentioned the symptoms incase one of you guys in the field recognise the problem. I was saving y'all reading the same old thing and using the archive as it's intended but with getting two totally different cures i's confusing to the layman.

When the DHW is opened the boiler fires but goes out after a few seconds then runs cold, the main burner doesn't attempt to fire. If I turn the room stat up the burner lights but the water is barely warm - certainly not HOT.

After thinking about it for a bit I presume the problem is a stat not letting the burner light.

Lastly, I've not had it serviced in the 9 years or so I've had it - had you guessed.

Cheers,

Ross

 

[Agile]

Now that you have confessed that you are not Gambian but Scottish then perhaps that follows!

I dont think I have ever suceeded in getting a cover off a Raven after nine years!

Now I am gretting confused about your boiler fault. I was relaxing and savouring my vermouth and expecting the others had correctly asimilated that the fault was the diverter.

Perhaps thats now in doubt.

Tony

 

[ROSSEDINBURGH]

"confessed . . . . that follows"? is that a between the lines joke about the Scots being tight? TSK, TSK, I feel abused now LOL

 

[ROSSEDINBURGH]

Hi again y'all,

it was the diverter valve. 3 hours work and parts for £99 through Scottish Gas - providing I took out parts and labour for £20 pm inc annual service. With an aging Ravenheat (that isn't really up to the job, I realise now) I jumped at it.

Thanks to those that replied and tried to help.

Ross

 

[Agile]

That comes to £339 in the first year.

Since I would probably change them for about £259 even though I hate the job that SG price would probably cover an Easyjet day return although they dont fly from LHR and probably dont go to your local airport either.

At least you have cover for the next year although you are unlikely to need it. If they are given a PROPER service they are very reliable apart from the diverter valve failure every 5-7 years.

Tony

 

[ROSSEDINBURGH]

Hi Tony,
their other option is to pay £149 for a one off repair without the £20 pm cover that rises to £249 if the job takes more than an hour. Now that it's fixed and back to peak performance, I realise it had tailed off over the years - it didn't just go overnight so will be getting my money's worth as regards cover!

 

[Agile]

I spoke to this fellow who used to do ravenheat repairs and he said he could change the diverter valve in 45min.

I would allow about 1¼ hours.

Somehow I have this idea the insurance engineers would always ensure it took over one hour!

Tony

 

[ROSSEDINBURGH]

Aye, I reckoned so too. he took just over two and a half and at one point was going to take it off the wall due to the position of the valve. He used fingerless gloves and came away without a scratch.