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Plumberpro, Plumber
Category: Plumbing
Satisfied Customers: 634
Experience:  Heating and plumbing answers. 20 years experience
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Hi i have a biasi riva compact 24sm, internal 3.15 quick blow

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Hi i have a biasi riva compact 24sm, internal 3.15 quick blow fulse fault this has gone twice. I'm an electrician and would off fault this maybe a input onto the main pcb board ? has anyone had this issue before.

Plumberpro : Hi . It sounds like it could be either the pump or the fan has gone and short circuiting
Plumberpro : How long was it before fuses blowing?

Hi the boiler will run

Plumberpro : Hello . I will try to help . How long before the first fuse blowing and the second ?

hi the boiler would run for some time and maybe the 3rd or 4 th time it runs ,it will blow its done this twice in the last two days ,so its not a dead short, the unit is about 4 years old.can i fit a inline fusle to pump or fan to see which is pulling the short.

Plumberpro : Hi . It sounds like it may be blowing when a stat gets upto temperature. . But you could test for ohms on pump and fan
Plumberpro : For pump , disconnect from pcb and should get 170-270across lL and N.
Plumberpro : fan should be 40-80ohms
Plumberpro : Has the heating been on when this happens ? Just asking because it's summer


Plumberpro : I would definitely check the thermistors f . At room temp the thermistors should read 9-11k ohms

yea no heating on, just hot water doing the tripping out, the shower was used today for about 10 mins with no problem and i would say sometime afterwards the boiler blow the fulse.


where are the thermistors are they shown on the diagram in the booklet

Plumberpro : Check the hot water thermistor . Also .im sure the internal fuse should be a 1.6 T
Plumberpro : The only problem with trying to diagnose a fault that is intermittent and not yet doing it all the time.
Plumberpro : I short of waiting till the faulty part fails , I would definitely start with the thermistors , if pump and fan seem ok
Plumberpro : Yes , if you have the mi s they should be there . I will see if I can find a diagram
Plumberpro : Yes they are in the main breakdown drawing . Do you have this?
Plumberpro : Also they are ntc not thermistors
Plumberpro : Easy to change .
Plumberpro : If you are going to replace them , replace the safety overheat stat at same time.
Plumberpro : Do you have the manual ? If not I have a link
Plumberpro : Hi . How are you getting on ?

not show if i have the break down drawing ,Im away from the manaul tonight if its in there should i be looking for a temperture probe.

Plumberpro : I managed to find it on line . It is here. . But if you need more help , just come back on.
Plumberpro : You want page 11. But they are easy to fit , as long as you shut off all the boiler isolation valves properly .

ok i will look at testing the probes and may if need be change them over.


thanks for your help in the matter.

Plumberpro and other Plumbing Specialists are ready to help you
Ok . All the best with it . If you need more help , just come back on .
Hi . Just wanted to let you know that if I remember rightly the ntc s might be dry pockets