Help please Ravenheat CSI 85

[zad]

Hello,

I have a Ravenheat CSI 85... yeah I know not well liked,but hey ho.

In the past I have had issues with boiler dhw going hot then cutting out then back on etc. CH has always been fine. I have or seem to have gotten lucky in the past twice now dropped the water and put cleaner in etc and its been fine until now 🙁

I had a new radiator put in last weekend moved from one wall to another. Since then the hot water has been the same firing up and going hot then cutting out. It normally comes on for around 40/45 seconds then straight off 15 secs later back on.

The CH pipe gets warm so engineer was thinking valve was passing as the diaphragm was doing its job. So I bought a new valve and two thermistors. he came back to change them this evening and gah its still the same 🙁

Please has any one any other ideas, he has suggested the plate heat exchange could be blocked? I have good flow rate to taps but its so up and down...

Thanks for looking and please any suggestions greatly appreciated.

Darren

 

[Billy Bob Bob]

the plate heat exchangers blocked,valve would have been knackerd any way after dumping down the flow

 

[zad]

Gas man, thank for prompt reply... is this a common symptom. I have no real idea how they work I thought they were 2 separate things.

Also just to note when we tried the new valve it passed to CH again. but only for a couple of mins will the new valve be broken now?

If it is a blockage does it need a new one or can it be cleaned?

once again thank you for prompt reply... 🙂

 

[coley]

Or the thermistors?

 

[zad]

Coley, I have already changed them m8 along with the new diverter as per original post...

 

[Billy Bob Bob]

the new valve should be ok the old one would have almost defiantly failed they can sometimes be cleaned but i would recommend a new plate heat exchanger as ingrained muck wont come out its only a common fault if you have a dirty system(and it sounds like you do)this problem will come back if you dont have the system cleaned and for ultimate protection a magna clean or similar cant be beaten

 

[stevetheplumber]

ive always manage to clean them with a hose and lots of tapping its usualy small particals stuck between the plates rather than scale actually stuck on the plates

 

[zad]

So the plate heat exchanger is in descaler since last night and engineer said leave till Wed night he will come back and try that. There was a bit of black hard stuff coming out just on putting hot water through it so guessing it might be block etc...

Fingers crossed fed up with what was a cold shower and now no shower lol... electric showers all the way next time 😛

 

[zad]

FIXED 🙂

Engineer came last night, we checked the crap that was coming out of the exchange etc and gave it a good blasting through with the hose 😉 and yeah it worked... talk about pain though disturbed pipes are bad but got there in the end....

So to sum it all up, Water was passing and hot water was running on and off. Changed diverter no difference, then cleaned the plate heat exchange with some descaler etc and it worked. So if it does it again I will buy a new exchanger 😉

cheers