Immersion Thermostat Help

[oliverdrums]

Hello,

I have had some awful dealings with Plumbforce Direct (www.plumbforcedirect.co.uk) and have decided to try to fix the matter myself.

They fitted a new immersion for us last Thursday (as the one they fitted in February started to blow the fuse) but on doing so they turned down the thermostat on the immersion as the water previously was close to boiling.

Sadly the water is now cold and I need to turn the thermostat back up. I looked on the diagram on the sticker on the immersion and there seems to be a dial inside that I can turn. Is it that simple?

Also, if I take out the fuse from the boiler switch on the wall will this cut all the power?

Thanks to anyone who can help.

 

[ChrisOxford]

I looked on the diagram on the sticker on the immersion and there seems to be a dial inside that I can turn. Is it that simple?

Yes! It should be (roughly) calibrated in degrees centigrade.

Also, if I take out the fuse from the boiler switch on the wall will this cut all the power?

NO! Unless by the "boiler switch" you mean the thing that the wire from the immersion heater runs into. To be on the safe side, do this AND switch off the mains to the whole house at the consumer unit (fusebox).

C.

 

[oliverdrums]

Excellent - cheers for your help Chris.

I read that the boiler shouldn't be over 65 degress - if I need to turn it higher than this to get the water hot would this imply a faulty immersion?

 

[ChrisOxford]

65 degrees is really very hot. If you set the stat to this and the water's tepid, something's wrong. Have you got access to a thermometer that would measure this kind of temperature?

BTW, "boiler" usually refers to one of those big white boxes on the wall connected to the gas supply. What you have is normally called a "hot water cylinder" [though I've heard that the Irish refer to them as boilers].

 

[oliverdrums]

No access to a thermometer - I was planning to do the test with my little finger!

At the moment it is lower than body temperature but I'm not sure what the temperature is set at.

And thanks for the heads-up on the hot water cylinder - if I need to call a plumber out now I won't sound like a fool

 

[ChrisOxford]

Don't forget it can take several hours for the water to get up to temperature.

Do you have one immersion heater, or two, by the way? And do you have electric storage heaters? Any timeswitches?

 

[oliverdrums]

It is a two immersion heater but only the lower one (states 'daytime' on the cylinder) is connected. It is only me and my Mrs in a one-bed flat so I don't think they ever connected both.

Not sure about the electric storage heaters and our old timswitch broke so it is now just an on/off lightswitch type of affair.

Cheers for helping

 

[ChrisOxford]

You need to make sure that the immersion heater is actually receiving power.

Does the "fused connector unit" (switch with a fuse, where the wire from the immersion heater is connected) have a red indicator light on it? If so, is the red light always on when you've switched the immersion on?

 

[oliverdrums]

I'm pretty sure it is doing something as the water hot water definitely feels slightly warmer than the cold water although this just might be because it's from the tank.

We have a 'light switch' on the wall which turns on the boiler (our timer broke in February too) and that has a 13amp fuse under the switch but no light. The immersion isn't connected directly to that though, I think it goes into another contraption first - this is all from memory though so I could be wrong...

 

[ChrisOxford]

Mmm, complicated!

Could you post us some pictures of everything, please?

The thermostat may be not actually be faulty!

 

[oliverdrums]

I'll be home in just over an hour so I will take some pics then.

Looking forward to the morning when I no longer have to heat water up on the stove!

 

[oliverdrums]

I had a look last night and you were right - the switch on the wall goes directly into the immersion.

I checked the thermostat and it was already on 60 degrees and I checked the fuse on the wall switch and that was working...

As we had a the immersion replaced last week I am guessing that is working fine so I assume it is something to do with the wiring (as you suggested!).

A sparky is coming around tomorrow morning.

Cheers again!

 

[ChrisOxford]

Good plan. Let us know the outcome.

I suspect that faulty timeswitch that you no longer use, but that's literally just a guess.

Immersion heaters take a fair bit of current, so the control gear takes quite a hammering.

 

[oliverdrums]

So the sage continues...

The electician came around yesterday morning and this is where we currently stand -

The power is reaching the immersion, the immersion has the correct resistance going through the element (so that is working) and the thermostat is working. Problem is when we turn it on it still cuts out after a minute or two (we checked this by watching the electric meter).

We have now connected the secondary immersion so we are only using the top half of the cylinder so we have a temporary solution.

The electrician said the most likely cause of this is to be limescale covering the lower thermostat so it is only heating up the adjacent water and reaching the set temperature quickly.

If this is the case what options do I have? Is it possible to manually remove the limescale or do I need a new boiler?

Also, as this is a new build flat the boiler is only four years old - do they come with a guarantee (it is an Aniston I think).

Cheers again!

 

[oliverdrums]

Bump!

Hopefully you'll see this Chris