fuse connection unit - safe to replace fuse

[jo75]

Hello,

Admittedly, this could be a dumb question but just wanted to double check the following.

I have a Pulsacoil 2000 boiler which gets electricity through a fuse connection unit. It has three switches for: 1. pump, 2. off-peak heating, 3.on-peak heating. Check here for picture: http://www.diynot.com/network/jo75/albums/2072/7798

Recently, the off-peak switch broke down but I could still use the boiler by using the on-peak switch. But during the cold spell the boiler broke down altogether (i.e. I could not get any hot water anymore, boiler would not at all heat up).

Before checking whether there's an issue with the boiler, I'd like to check the electricy supply. Would it be safe for me to take out the fuse near the switch and replace it with a new one? I have a feeling it may have been belown. Is it enough to just keep the switch switched off and then open the fusebox, or should I switch off electricity altogether?

Any advice much appreciated!

Thanks so much,

Jo

 

[securespark]

Can you post some pix?

 

[jo75]

Thanks, there is a picture here: http://www.diynot.com/network/jo75/albums/2072/7798

 

[electronicsuk]

Before checking whether there's an issue with the boiler, I'd like to check the electricy supply. Would it be safe for me to take out the fuse near the switch and replace it with a new one? I have a feeling it may have been belown. Is it enough to just keep the switch switched off and then open the fusebox, or should I switch off electricity altogether?

Yes, you can turn off the DP switch on the FCU itself and then replace the fuse in the carrier. Replace with one of an identical size, assuming that what's in there already seems sensible given the size of the load.

Also, I assume this 'boiler' is actually what we'd refer to as a hot water tank, some kind of pumped thermal store? If it's taken out both fuses than a fault with the unit itself seems very likely. If the pump is part of the 'boiler' then that should probably be left on at all times when it is heating, as (unless it's a booster pump for a shower or the like) it may be required to circulate water in the system.

 

[jo75]

Many thanks. You are probably right that it is more like a hot water tank than a boiler. Not too sure about the semantics but it's basically one of these: http://www.gledhill.net/water-storage/2000-range-index/pulsacoil1.htm

The pump switch indeed always needs to be on. I've had many problems already with this boiler but usually when I've got problems I'm able to get some hot water though not enough. However, this time, I'm not able to get any hot water whatsoever and also whenever i switch on the on-peak switch (off-peak switch broke down some time ago already), the unit no longer heats up. I seem to recall that I used to hear a sound before that it started to heat up. It doesn't happen anymore so that's why I'm suspecting it may be a problem with the electricity supply rather with the boiler. Or at least, I want to rule that out before calling a plumber yet again.

I'm going to check this tomorrow and replace the fuses and see what happens then.

Thanks again so much for your help!