Immersion heater - 2 questions

jcontest

That's just a Thermostat.
http://www.thermowatt.com/en/product/122


It's just a on-off switch and nothing more. It should Open (cut electricity off) once it's above temperature. The heating elements are a on-off only item, They don't adjust the amount of power going in to give a different heat level.


I think your other thread has some people who deal with these things, and they are probably the best to give advice.


Your Relief valve is opening up. So that's one of three things (to me).
A faulty valve (possible if the unit is 10+ years old and it's never been changed), a faulty temperature sensor, or too much pressure in the system.


I don't see why a plumber couldn't fix this issue, I think they are just looking to sell something new.

ssm90

jcontest wrote: »

That's just a Thermostat.
http://www.thermowatt.com/en/product/122


It's just a on-off switch and nothing more. It should Open (cut electricity off) once it's above temperature. The heating elements are a on-off only item, They don't adjust the amount of power going in to give a different heat level.


I think your other thread has some people who deal with these things, and they are probably the best to give advice.


Your Relief valve is opening up. So that's one of three things (to me).
A faulty valve (possible if the unit is 10+ years old and it's never been changed), a faulty temperature sensor, or too much pressure in the system.


I don't see why a plumber couldn't fix this issue, I think they are just looking to sell something new.

That's my concern as well. Everyone I have contacted has quoted atleast £200 for the expansion vessel and £300 for thermostats.

With regards to the thermostat just being on/off, I'm not sure this is the case as the dial is able to move smoothly from one end to other and can be set at any point rather than just on min (-) or max (+) just like a dial on an electric heater for example. However, it does seem to be working on the max setting so I am not inclined to get these replaced for £300.

For the expansion vessel, the more I read up, the more I am convinced that the diaphragm in the vessel isn't burst as there is no water coming out when I press the pressure relief valve on the top of the expansion vessel. It seems that the air pressure is too low within the expansion vessel and therefore the water is pushing the diaphragm all the way up. I have looked at recharging the vessel, but all guides suggest I need to isolate the expansion vessel by removing it from the system, for which you need a G3 certificate so I am back at square one with needing a plumber!

ianto11

ssm90 wrote: »

That's my concern as well. Everyone I have contacted has quoted atleast £200 for the expansion vessel and £300 for thermostats.

With regards to the thermostat just being on/off, I'm not sure this is the case as the dial is able to move smoothly from one end to other and can be set at any point rather than just on min (-) or max (+) just like a dial on an electric heater for example. However, it does seem to be working on the max setting so I am not inclined to get these replaced for £300.

For the expansion vessel, the more I read up, the more I am convinced that the diaphragm in the vessel isn't burst as there is no water coming out when I press the pressure relief valve on the top of the expansion vessel. It seems that the air pressure is too low within the expansion vessel and therefore the water is pushing the diaphragm all the way up. I have looked at recharging the vessel, but all guides suggest I need to isolate the expansion vessel by removing it from the system, for which you need a G3 certificate so I am back at square one with needing a plumber!

Thermostat is just an on/off switch...the -/+ merely alters the set point it switches on/off at, full to minus might be 40degC..full to plus might be 60 deg C.
As to the repair...I appreciate a total of £500 is a lot, but surely hugely preferable to the 2K+ you were quoted for a cylinder replacemnt

molerat

The £300 is most likely to change the heater elements. The stats are around £20 each and easy to change, the elements are under £50 each but can be a pig to change. You could set those thermostats at mid point rather than max, you should be able to hear / feel them click on and off if you move the dial gently. Also can you show a picture of the wires going into the wall, they should not both be connected together, the lower one should be connected to the E7 circuit and the top to the peak electricity. Getting a G3 qualified plumber in to look at it may be money well spent, I suspect your electrician is not the best qualified person to diagnose the problem.