Ravenheat RSF 100ET Boiler problems

Hi! I've had a series of problems with my Ravenheat RSF 100ET combi boiler. It's about 6 yrs old and ran perfectly for 4 yrs or so. I have had to 'thump' it from time to time (at the top) to get it going, then the clock went haywire - solved by installing a new one.

Then the boiler would 'click' fire up and go out again when the hot hot tap is used - wiggling the thermister on the DHW sorts this out, but I haven't changed it yet.

Now, when I run the domestic hot water the central heating gets warm at the same time.

I installed a new diaphragm in the 3-way diverter valve, but it didn't help. The diaphragm spindle actuates the microswitches as it is supposed to do, but when the hot water tap is used the CH still gets warm.

Is there another shunt or valve inside the body of the 3-way diverter that could be stuck? I'm tempted to put in a complete new valve, but am a bit stumped by the three types that are available (types D, E and F) - all of which have the two smaller feeds (non CH) at right angles to each other, whereas mine has one at the top and one at the bottom, with the flow adjustment screw at the top (all the valves i've seen for sale seem to have the flow adjustment screw at the bottom).

I wondered if anyone has any practical experience of this and can guide me?

Thanks,
Neil.

I interpret your posting as describing someone who knows there are problems and doesn't bother to sort them out. Presumable because you hate spending money.

You have not been looking at the manufacturer's genuine parts either ! Only generic types which may or may not fit your boiler. Each of those letters describes a layout of 3-D pipe connections.

As you have correctly guessed the manifold of the diverter contains a shaft which follows the diaphragm unit under the pressure of a spring at the opposite end. If that sticks or is sluggish it lets heat into the rads. Thats usually as a result of dirt in the system so that probably needs cleaning too.

Whilst commercially we would always replace the whole valve, to help you save money you could always dismantle it and clean the manifold section to see if you can get it to move freely.

I did that as a favour to a friend recently but in spite of all my experience and including boiling in citric acid solution it still was letting by a little although much improved. Now I have to get him a replacement.

Please change the sensor if thats defective.

The other option which I dont expect you will follow would be to get a competent boiler engineer to sort out all the problems at once.

Tony

Tony: I don't hate spending money, I just haven't any to spend. Big difference! And as for not bothering to sort problems out - please! Why do you think I am posting here?

I haven't renewed the thermister yet for the simple reason that I have just discovered it is faulty and to replace it I will have to drain the system again - and I might as well do that when I replace the 3-way valve - makes sense, does it not?

You could well be right about the valve parts not being genuine manufacturers parts (one out of three isn't bad!) but I have sourced them from the same place that supplied the clock (another problem which I have sorted out) and that was a genuine part - but about 30% cheaper than from Ravenheat. If a pattern-part will do the job well, what's the problem in that? I don't expect for one minute that Ravenheat manufacture all the parts they use, do you?

The shaft in the converter moves freely now. When dismatled, everything looked quite clean for it's age - but the rubber of the diaphragm was very stiff and perished, although not split or holed.

Thanks for the practical advice about cleaning the valve - if you didn't have any luck doing it, I don't think I'll bother trying.

by the way, I have arranged for a competent engineer to call - once I have eliminated all the more common variables. I can't see any sense in paying someone to perform a process of elimination when it's not necessary.

I'm trying not to be as negative as you, Tony, but when someone like you jumps to (false) assumptions it's very hard not to!

Regards,
Neil.

No need to drain the system, Issolate at bottom of boiler and drain off.
Drain hot taps and on you go.
open issolation points and top up system.

(types D, E and F) - all of which have the two smaller feeds (non CH) at right angles to each other,

Click to expand...

3 types couldn't all - think about it!
You need an F, which is "opposite"

Thanks!

clf-gas: that's what I'll do, thank you!

ChrisR - I think the manufacturer's website is confusing me here - it looks like they have used the same pic with the 90 degree off-set for each item. I'll go for the 'F' as you suggest, thank you.

Thanks again for the considerate and positive postings, I'm much obliged to you both.

Regards,
Neil.

I had a similar problem with my Ravenheat 84 (99% the same as your 100).

I replaced the entire diverter with a generic cheapo one from BES/Banico, as the HW pin was not activating reliably. The new one activated perfectly, but decided to pass to the CH when the HW was in use. I suspect yours is at the same stage (even if it's a Ravenheat original).

In the end, I took the diaphragm out of the Banico valve and placed it into the original Ravenheat valve. Worked perfectly ever since.

Moral: the cheap valves are rubbish. Spend the extra on a real one!

As an aside, I also found the thermistors (AND the cables joining them to the PCB) worth replacing.

Thanks richw!

I have ordered a complete new 3-way giannoni (I think you spell it like that!) valve - it looks exactly the same as the one in the boiler so it might be an original part, and two genuine Ravenheat thermisters. I didn't think to order new leads to go with them - that's a smart idea you had that I wish I had thought of!

I just hope that all the parts come with washers - fingers crossed!

Kind regards,
Neil.

Well, the 3-way diverter valve and the thermisters arrived today, but not one damn washer between them. Marvellous.

The valve is supposed to ba Giannoni type 'F' (DV.130), with an "F" moulded into the body and "193406H4" engraved on it. It doesn't look like the number on the one in the boiler, but it's hard to see properly until it's taken out.

If you look at it from the microswitch side, the feeds are in a "10 past 12" angle to use a clock as an analogy.

The inlet feed with the filter is at 10 past position - it should be opposite the other one, at the bottom, where "6" would be on a clock.

The other part of the valve with the three larger feeds has grub screws on either side, so maybe I can rotate the filtered feed (nearest the grub screws) to the right position if I slacken them, then tighten them again.

Does anyone know if it's as simple as that, or is there anything else I have to do to save myself from generating a leak? I wish the damn thing was in the right position to begin with!

If it can be rotated, I will then have to undo the 8 screws holding the cover with the other feed on it and put it in the right position. I know I won't get a leak from here, because I have already undone one before to fit a new diaphragm.

I can't believe no washers were supplied (and no, I don't need the 'you get what you pay for' and the 'competent person' reminders by you-know-who: try being nice for a day).

Regards,
Neil.

I finally found the right washers - after a trip to 5 plumbers merchants. The big one at the back of the diverter was particularly hard to get.

I succumbed to temptation and loosened the grub screws, rotated the diaphragm housing, undid it's cover and reorientated the other inlet - everything looked OK, so I fitted it.

Also fitted the new thermisters (to the old cables) and topped-up the boiler with water to the correct bar level.

No leaks - yet, the diaphragm moves up and down in response to the hot water tap being turned on/off (spindle activates the microswitches when hot tap is turned on) but...

...when I turned the power on and tried the hot tap, the water got scaldingly hot (temp. setting only turned halfway) and the boiler began to sound like a kettle beginning to boil. Quickly turned off the hot tap, turned off the power, and let the water run cool again.

Now I'm stumped.

Regards,
Neil.

The problem was a faulty (new!) thermister - worse than the old one! Replaced it with another new one and no probs.

Problem solved.

Thanks again for help and advice.

Regards,
Neil.