Ravenheat condensing CSI Primary boiler has been cycling .I think the problem might be the controle thermostat.I checked the flow temperature at the boiler ,it seemed to be cutting out at 61deg (if the guage was right)I then removed the thermostat probe from its housing and the boiler worked fine ,temp went up to 85deg,no cycling,(it used to cut out at varaing times between5&90 seconds)I switched the boiler off before the overheat thermostat came into play.Ive been quoted £40 for the part at a plumbers merchants.I would appreciate any helpful comments on this problem.Thanks.
Is this right.
- Thread starter hmk
- Start date
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Not familiar with the boiler but if it's a combi put the dhw thermister in to the primary side temporarily and see if the problem persists before spending £40 which by the way is hugely expensive. Even the over expensive Halstead one is only £20 with the vat.
What colour is it? Green? Ariston may fit, just a few quid. Blue? vokera one few quid also.
Most are wet pocket so need a drain down to change unless you can work with a jet of water squirting at your eye, we sometimes do them live but occasionally this involves a trip home to borrow the wifes hairdryer and get the pcb dry before making it live again. In your case best drain down.
What colour is it? Green? Ariston may fit, just a few quid. Blue? vokera one few quid also.
Most are wet pocket so need a drain down to change unless you can work with a jet of water squirting at your eye, we sometimes do them live but occasionally this involves a trip home to borrow the wifes hairdryer and get the pcb dry before making it live again. In your case best drain down.
Thanks Paul,its not a combi & its not wet,it fits in a sleve braised on to the flow its about 75ml long & 10mil in diam copper colour with a thin copper wire/pipe going to the switch which is obout 40ml square all part & parcel as i see it.Some Plumber Must Be Familar With Ravenheat.
The part paul is talking about is directly below the stat you`re describing. It screws into the same pipe, should see green plastic fitting with 2 red wires leading to it. Opposite side of the boiler is another thermistor, this has 2 blue wires leading to it, as paul says, swap the 2 temporarily and see if the problem persists.
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While what you say does logically point to the stat as you suspect however I have not found one to go wrong yet. I would be checking the more usual causes of cycling on these before replacing the stat.
Number one cause is usually a thermistor on a Ravenheat but as you said you have a stat.
Its a case of going round and checking everything else before you start swapping bits.
Forget logic for a while and check the following.
Number 2 cause : - Where the red venturi tube goes onto the flue restrictor ring check that this is at 90º to the direction of the flue
While you are there
Check the tubes are intact and not kinked
Check that the flue is intact and that the fan has not started to sieze up. Also check the flue is in compliance with the manufacturers instructions
Number 3 cause: - There is an issue with the spark electrode / flame sensing wire. Take the condensing unit out of line. Cut or disconnect the wires to the condensing unit and join them together with a good wrap of decent electricians tape [get a replacement one piece wire later as fitted to non condensers] Dont worry about his mod as I have been told faithfully by Ravenheat that this is OK and it has worked on several occasions.
At this point your outlay will be minimal
Hopefully you will have it sorted by this stage and now its back to logic and perhaps time to get someone in who knows about these boilers and has a few spares kicking about to eliminate or otherwise test to get to the cause.
Number one cause is usually a thermistor on a Ravenheat but as you said you have a stat.
Its a case of going round and checking everything else before you start swapping bits.
Forget logic for a while and check the following.
Number 2 cause : - Where the red venturi tube goes onto the flue restrictor ring check that this is at 90º to the direction of the flue
While you are there
Check the tubes are intact and not kinked
Check that the flue is intact and that the fan has not started to sieze up. Also check the flue is in compliance with the manufacturers instructions
Number 3 cause: - There is an issue with the spark electrode / flame sensing wire. Take the condensing unit out of line. Cut or disconnect the wires to the condensing unit and join them together with a good wrap of decent electricians tape [get a replacement one piece wire later as fitted to non condensers] Dont worry about his mod as I have been told faithfully by Ravenheat that this is OK and it has worked on several occasions.
At this point your outlay will be minimal
Hopefully you will have it sorted by this stage and now its back to logic and perhaps time to get someone in who knows about these boilers and has a few spares kicking about to eliminate or otherwise test to get to the cause.
Slugbabydotcom said:
If there is an interuptor in the condensing unit it would probably there to monitor flue gas temperature and prevent it melting the non metal exhaust, unles you know better? If this is so and it is found necessary by the manufacturer to bridge it to prevent above problem, seems to me the whole boiler wants a redesign, what they are really saying is that they can't get the flame to modulate down sufficiently for condensing operation without short cycling.
An advert for a band A boiler if ever there was one.
I am really excited that band A boilers are now geting down towards the band B price bracket.
No its there to monitor the trap for blockages which they say never happen anyway.
One of the points I didnt mention is that the modulating gas pressures would need checking and setting. The reasons I didn't mention it are firstly because this is generally too far removed from the domain of a DIYer and that there was a whole bunch of the less likely stuff to go through, mostly in the domain of a manufacturer trained or otherwise 'competent in the field of repairs' corgi engineer.
hmk has diagnosed that the stat is likely to be faulty. This is so rare for this boiler that I am questioning that and eliminating some of the cheapest easiest common possibilities that I feel are in scope of this competent DIYer before he starts throwing money at it.
The reason that these are band A boilers in the band B price bracket is that they are the most efficient atmospheric boilers and AFAIK the only atmospheric boilers in band A when on nat. gas
Thanks to all for your help.Re the condensing trap,its shown in the manual on L H S just inside the pannel,but on this one its somewhere behind the cumbustion chamber.I think its beyond my ability now.Just one more question,if it is other faults as suggested would removing the thermostat probe from its housing cure them, because the boiler seemed to work fine while it was out.
No that is dangerous!
They started putting them there as they became more confident that they wouldn't block up. I have had the fun of trying to get to them as well but they are stuck on with double sided tape.
If this condensate trap sensor isnt a problem now, then it will be sooner or later. You will see 2 white wires going to it. One from the ignition box that is stuck on the gas valve and the other leads to the combustion chamber.
Simply cut the 2 wires as close as you can to the trap leaving enough, and there should be plenty, for you to join them together. Effectively creating a link from ign. box to combustion chamber. Just bare the ends and make an electrical connection with a 5amp block connector then tape it up with good quality electricians tape.
Did you undo the 13 screws and check the position of the venturi?
Whereabouts in Yorkshire are you? If you can buy a 'parmo' locally then there is a good chance that if you ring Ravenheat they will give you my number if you ask them for an approved installer.
A parmesan. Its what us smoggies eat. You would have to come to Boro to get a decent one. Although I did get an ok one at a takeaway in Loftus
I was at nearby Stainsacre Hall for New Year as it happens. I can often be seen sat on the wall over the road from Mr Chippy eating fish and chips.
As yer do
Best chips in town. I have ordered a thermostat on agreement if it doesnt work i can take it back and get a full refund.The part should be here on tue/wed,will keep in contact.I dont feel confidant to dig any further. How will i know its you sat on the wall.
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