C/H boiler problem

[Brumas]

Hi. I have a Combi Ideal Classic 280 C/H boiler. The hotwater is working fine but the hot water blows the main house fuse. Every time I switch to central heating from hot water only, The fuse blows again. Any ideas please. Note the fuse from switch to boiler does not blow.

 

[gas4you]

I assume you mean a heat only classic 280? Check the hot water zone valve, it sounds as something is tracking to earth in this. I assume you mean the RCD is tripping?

 

[Rob]

Is you HW gravity? If so disconnect the pump and try again.

If its fully pumped i.e your pump is already on for HW then its possibly a motor valve, room stat, nail through cable fault!

 

[bengasman]

Note the fuse from switch to boiler does not blow. [/quote

You probably (hopefully) mean what is commonly referred to as a “spur”.
Check what fuse is in there, should be a 3 amp, but probably is 13 amp.
Has anything happened that could have damaged pump, stat, timer, mv, boiler or wiring by any chance? Drilling in wall, wire pulled loose etc?

 

[Brumas]

Is you HW gravity? If so disconnect the pump and try again.

If its fully pumped i.e your pump is already on for HW then its possibly a motor valve, room stat, nail through cable fault!

Thanks Rob. I will chase up your suggestions. RTP.

 

[Brumas]

Note the fuse from switch to boiler does not blow. [/quote

You probably (hopefully) mean what is commonly referred to as a “spur”.
Check what fuse is in there, should be a 3 amp, but probably is 13 amp.
Has anything happened that could have damaged pump, stat, timer, mv, boiler or wiring by any chance? Drilling in wall, wire pulled loose etc?

3amp fuse not affected. Timer is above this. I don't understand why the main house fuse blows. Have checked all areas sharing this circuit.
Regards. Brumas

 

[gas4you]

As in my e-mail, I think what you describe as your main house fuse is the RCD.

This will trip only on an imbalance between L & N, so therefore current is going to earth to cause this imbalance.