Ravenheat LS80 no DHW, thermistor and diaphramn changed

[Andygasman2010]

I get the type of diverter/microswitch you have now. The principle is the same though, movement created by the diaphragm operates the microswitch and brings the hot water on, does this sound right? If so, then the previous advice is still valid.

With the pressure gauge moving, what i meant was that the water coming out of the the tap isn't the same water as the gauge senses. If you think it is, and you're sure, then it's faulty.

You tried a complete new diverter valve?

 

[Mickymoody]

Yeah, that picture is right (but in bits), flow switch, 3 way valve, nothing attached to end of diaphramn.

Once again, when flow switch is removed, hence open, boiler fires, and remains fired, regardless of timer operation. Water Cold.

When flow switch fitted as normal, CH fires when requested, Water cold.

After the 'engineer' came out, after the CH had been on, boiler fired of it's own accord, and leaked suspected from where in the picture the diaphramn is, and its cover. Presumably the flow switch was displaced?

Now, that flow switch, having two wires, is it a simple on/off, or have a 3rd option for HW? As the microswitch just clicks on/off.

 

[Andygasman2010]

If the switch is two wires the it'll just be make/break.

Sounds to me like the mechaincs of the diverter valve aren't operating the switch propperly when it's fitted around the diverter body.

Another thing, maybe the switch works the opposite way round to normal i.e. open circuit creates demand rather than continuity.... just a thought.

Maybe it's time to replace the complete diverter valve.

 

[Mickymoody]

Maybe it is time to replace the divertor valve; but I was told 100% thermistor is faulty. And it wasn't. then 100% diaphramn, and that was faulty, but didn't fix the problem, now its divertor.

In the manual it refers to flow rate, how is that determined? As if flow rate is too low, it won't work? ie when it did work, if the tap was run at a dribble, then the boiler didn't fire, until tap turned on fully.

 

[Andygasman2010]

Given the length of this thread and seeiming going round in circles I wouldn't say anything was 100% anymore! At least the diaphragm and the thermistors are quite cheap.

The manual will probs give you a minimum flow rate, maybe about 2lpm? This is the minimum threshhold that'll make/break the flow switch. As far as the flow switch is concerned it's either on or off, it's not variable between min/max quoted flow rates.

It sounds to me like the mechanism that operates the switch when in situ isn't working propperly....

 

[enb54]

This is an interesting problem. Was wondering if you have the same Ravenheat LS80 installation and operating manual I looked at located at http://www.ravenheat.co.uk/pdf/manuals/LS80printV3.1.pdf to ascertain exactly what is supposed to happen and when with your boiler unit. Have managed to maintain an (according to many HVAC contractors here) obsolete "piece of junk" Amana HTM with very little expense as long as annual maintenance is carried out, for the last 30 years (many years experience in electronics, but am not a HVAC tech).

Having read through this thread, you have a combination Domestic Hot Water (DHW) and Central Heating (CH) boiler system, utilizing an on-demand DHW circuit. I have a similar system, except I have a 40 (U.S.) gallon hot water storage tank.

Most likely, when you have your control switch set to "Winter" you are going to follow this general sequence of events: Thermostat completes the call for CH operation, starts fluid circulating pump, combustion fan, turns on ignitor, then opens gas valve and combustion occurs (takes about 40 to 60 seconds), control circuit monitors for high water temperature and possibly high pressure/low water level, cuts off gas flow when target temperature for CH reached or if problems detected. The fluid circulator pump usually continues to run for some time after burner shut down. While operating, if the system senses that you are wanting DHW, a diverter valve operates to direct the high temperature circulating water going to your home radiators for CH to close and circulate in a closed loop to heat the DHW coils in your DHW heater/storage tank portion of your boiler system, or if the boiler capacity is high enough, to send the hot water directly to your hot water tap. Summer operation is basically the same, but with the CH part of the circuit excised.

When my system calls for DHW, I can physically touch the diverter valve outlet to the DHW and the piping feels very hot, plus vibrations indicating the circulating pump is working. When the diverter valve switches over to supply the CH system, you can also feel the increase in temperature to the heating part of the circuit, with a subsequent slow cooling of the DHW side of the valve. Very basic thinking about your problem would lead me to the diverter valve or your DHW heat exchanger (seems unlikely) or your DHW pipe leading away from the boiler (blockage of some kind?), as there seems to be absolutely no hot water no matter what you do, but you do have the CH function. These systems are usually straightforward unless someone has miswired something or mis-programmed the control unit, wish you success in troubleshooting this to a positive outcome. Hopefully this information is of some assistance, I’m surprised this thread has become so long, but maybe I’m missing something…

 

[twgas]

I've just read through this thread, I know it's sad, and believe one of your problems is the information you're giving (albeit with good intention).
You really need to give direct straightforward answers eg. question; when you turn the hot tap on do rads get hot? answer; yes (or no) - do not give other info like; no but if I switch the summer switch to on the pressure drops.

 

[Mickymoody]

Yeah, it is sad that the thread has become so long..I admit I tend to ramble twgas, as I try to explain everything as fully as possible, on a subject that I have little knowledge, but lots of info.

Enb54 - I have the operating manual, with veng diagrams, and flow charts to determine faults, and also downloaded the same manual from Ravenheat, so yes, same manual.

It has been confirmed in this thread that the 3-way divertor valve is now the most likely fault, and independantly, so until that part is replaced (which I can't afford at present), then I cannot see this thread progressing.

Add to that the fault(s) introduced when the diaphramn was replaced (the boiler leaking, and firing up even when switched off, just confuses the situation.

Sorry to disappoint you twgas. Lots of useful info enb54, wish you were there at the start.

 

[Agile]

I am sorry that you find that posting by Enb54 of any use.

He is someone with plenty of time to read the manual and then to just rephrase what it says again. He has never seen one and is not qualified to work on them.

Most of the rest of us are gas qualified and WE do work on them and some of us are very familiar with your model.

Unfortunately you are not very good at answering a simple question with a simple answer without bringing in additional and sometimes confusing information.

Your boiler is a very simple piece of equipment compared with an Airbus 320.

Tony

 

[Mickymoody]

I am sorry that you find that posting by Enb54 of any use.

He is someone with plenty of time to read the manual and then to just rephrase what it says again. He has never seen one and is not qualified to work on them.

Most of the rest of us are gas qualified and WE do work on them and some of us are very familiar with your model.

Unfortunately you are not very good at answering a simple question with a simple answer without bringing in additional and sometimes confusing information.

Your boiler is a very simple piece of equipment compared with an Airbus 320.

Tony

He directly answered the question posed, I asked how does the system work, he answered logically, from a technical point of view, but in language that I understand. You just slagged him off, and didn't answer anything, like the 4 engineers employed to repair two boilers that have failed. The engineers just say Ravenheat boiler? pile of crap! If they are so rubbish, then someone must have experience of fixing them, or is the markup by rubbishing them, and fitting a new boiler for profit? Where that boiler when it breaks down after the warranty runs out another pile of crap?

If my boiler is so simple, and so obviously full of common faults, then why run a thread to 5 pages? With contrite and conflicting information, that has often been incorrect, or someone disagreeing with another, or someones 'opinion'

Seems like an electrical engineer (as myself), has the logic to decode logical fault finding guides, published by the manufacturer, but gas registered engineers guess, and swap parts ad-hoc, and slag off others that have an opinion. As has been my real world experience, as well as on-line experience.

I put your post down to over-exuberance, I just want closure on this, it's not nice to be slagged off twice in a thread, where I just ask a question.

In my business, I'd be sacked for swapping parts ad-hoc, theory random decisions, the device doesn't do xyz, it needs part a. end of fixed.

Not it needs this..oh no..thats wrong..oh it needs this then..nope..oh well this must be wrong..

BTW one of my mates designed the wings for the new Airbus..so a rather inappropriate comment..if you have nothing positive to say, then don't say it.

 

[Agile]

You seem to have forgotten that I posted SIX replies on just the FIRST page of your thread. Probably several more as well.

Nor do I advocate parts changing.

I have tried to help you objectively and without argument. Unfortunately it became too difficult as we were not getting simple or consistant replies.

I am sorry that you have not appreciated my attempts to help you!

Would you have preferred me not to have tried to help you?

Tony

 

[Agile]

BTW one of my mates designed the wings for the new Airbus..so a rather inappropriate comment..if you have nothing positive to say, then don't say it.

According to the Airbus web site:-

At Filton, over 4,500 people are employed in the design office and in business support roles such as procurement, finance and customer service. Core activities at Filton include the design, engineering and support for Airbus wings, fuel systems and landing gear integration. Teams also work on systems, structures, and aerodynamics research, development and test facilities.

Is your mate just one of the 4500 ?

 

[Mickymoody]

People are complaining that the thread is too long....so you adding 6 posts on the first page don't help does it? Then you started an argument around page 3, thanks for the help; but my boiler don't work. Infact it's worse now, than when I started the thread.

WTF are you doing Agile? Have you responded to my OP topic? NO. You are just spamming.

Where in your post does it respond to my OP question, MY BOILER IS FUBAR, NO HOT WATER?

You talk about employee statistics in Airbus manufacture? A little off topic maybe?

 

[Agile]

I added the six replies on the first page to try to help you. I also added several more on later pages.

I have just looked through what I have written and I am pleased to say that I have given some very good advice which put together would enable anyone to repair one of these boilers.

The fault charts sometimes included by manufacturers are not intended to create a comprehensive repair guide but merely an attempt to help the less able to identify simple faults.

Tony

 

[Mickymoody]

I added the six replies on the first page to try to help you. I also added several more on later pages.

I have just looked through what I have written and I am pleased to say that I have given some very good advice which put together would enable anyone to repair one of these boilers.

The fault charts sometimes included by manufacturers are not intended to create a comprehensive repair guide but merely an attempt to help the less able to identify simple faults.

Tony

But none of the advice worked. In fact it created more expense.