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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

Customer Question

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.
Submitted: 3 years ago.
Category: Plumbing
Expert:  Plumberpro replied 3 years ago.

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 2 other Plumbing Specialists are ready to help you
Expert:  Plumberpro replied 3 years ago.
Ok . All the best with it . If you need more help , just come back on .
Expert:  Plumberpro replied 3 years ago.
Hi . Just wanted to let you know that if I remember rightly the ntc s might be dry pockets