Immersun Overheating Hot Water

Minrich

We have had Solar panels for 5 years. We have an immersun fitted to heat the water . Since having the installation the hot water has been very hot. During the five years we have had the panels we have had to have three new water pumps for the power shower. It is my belief that the very hot water has damaged them. I am about to install the fourth pump but am going through a process of trying to find the reason. I will be sending off the most recent broken pump to diagnose the reason it failed.
Now i believe the immersun is heating the water and not turning off. The Hot water tank thermostat Is only linked to the central heating control box and no thermostat is attached to the immersun. So i believe it has been installed incorrectly and am taking it up with the company who installed it.
Has anyone else had this issue and how was it resolved ? Comments ? Should i seek compensation from the Solar installer?

Cardew

Are the solar installers, of the immersun, still in business? by that I mean has the firm still the same name?

Minrich

Cardew said:

Are the solar installers, of the immersun, still in business? by that I mean has the firm still the same name?

Yes. Very professional long standing business with a Solar arm.

Ectophile

You need to check the thermostat on your immersion heater.  The Immersun will keep sending power to the immersion heater until the thermostat switches off.  If that thermostat is set too high, or is stuck closed, then you will end up with water that's too hot.  The Immersun itself has no idea how hot the water is.

Minrich

Ectophile said:

You need to check the thermostat on your immersion heater.  The Immersun will keep sending power to the immersion heater until the thermostat switches off.  If that thermostat is set too high, or is stuck closed, then you will end up with water that's too hot.  The Immersun itself has no idea how hot the water is.

My Immersion does not have a thermostat, that is the problem. Prior to solar install we might have used it twice in 30 years. You plug it in an leave for 20 mins and then unplug. Do they come with a thermostat included now ?

Minrich

Minrich said:

Ectophile said:

You need to check the thermostat on your immersion heater.  The Immersun will keep sending power to the immersion heater until the thermostat switches off.  If that thermostat is set too high, or is stuck closed, then you will end up with water that's too hot.  The Immersun itself has no idea how hot the water is.

My Immersion does not have a thermostat, that is the problem. Prior to solar install we might have used it twice in 30 years. You plug it in an leave for 20 mins and then unplug. Do they come with a thermostat included now ?

I think there must be one.... i think it is under the cap on top of the cylinder. I think thats the problem, not the one on the side. I think replacing the whole immersion heater and thermostat should solve my problem.

Hexane

I think your immersion heater might have a thermostat even if it doesn't look like it has. To give an example, my gas boiler fired hot water heating has what I would traditionally recognise as a thermostat, which is to say a round dial type control with numbers on it (in centigrade in this case) that I can turn to choose an on/off temperature. However my electric immersion heater also has a thermostat, which doesn't look anything like that. It's a four-position setting underneath the metal cover of the thermostat housing (therefore inaccessible to anyone without some kind of tool to open the cover). Its default setting is well over 70C, so much hotter than most people would set their ordinary hot water thermostat.

Minrich

Hexane said:

I think your immersion heater might have a thermostat even if it doesn't look like it has. To give an example, my gas boiler fired hot water heating has what I would traditionally recognise as a thermostat, which is to say a round dial type control with numbers on it (in centigrade in this case) that I can turn to choose an on/off temperature. However my electric immersion heater also has a thermostat, which doesn't look anything like that. It's a four-position setting underneath the metal cover of the thermostat housing (therefore inaccessible to anyone without some kind of tool to open the cover). Its default setting is well over 70C, so much hotter than most people would set their ordinary hot water thermostat.

Yes i am sure that there is one. I will investigate and replace the whole thing. May need one of those spanners to get the old one out. Might be a problem , its been in situ over 30yrs.

DiggerUK

Minrich said:

Hexane said:

I think your immersion heater might have a thermostat even if it doesn't look like it has. To give an example, my gas boiler fired hot water heating has what I would traditionally recognise as a thermostat, which is to say a round dial type control with numbers on it (in centigrade in this case) that I can turn to choose an on/off temperature. However my electric immersion heater also has a thermostat, which doesn't look anything like that. It's a four-position setting underneath the metal cover of the thermostat housing (therefore inaccessible to anyone without some kind of tool to open the cover). Its default setting is well over 70C, so much hotter than most people would set their ordinary hot water thermostat.

Yes i am sure that there is one. I will investigate and replace the whole thing. May need one of those spanners to get the old one out. Might be a problem , its been in situ over 30yrs.

What you seem to have on the top is the thermostat, if you take the cap off you should be able to see what it is. It must be set at a minimum 60°C to keep you safe from legionaries disease,  the bit on the side sounds like it is the heating element. As you describe a very odd situation it could be the other way round.

Can I ask how you heated the water in the last thirty years if you only plugged in the immersion twice. They use such a high volume of power that they are normally hardwired in to a fused switch box, not a plug and socket..._

Ectophile

DiggerUK said:

Can I ask how you heated the water in the last thirty years if you only plugged in the immersion twice. They use such a high volume of power that they are normally hardwired in to a fused switch box, not a plug and socket..._

Most immersion heaters in the UK are a maximum of 3kW, or 13A.  So there's no reason it couldn't be put on a plug.  If it's on a fused switch, then the fuse is probably 13A.

For many people, the immersion is only a back-up in case the gas boiler goes wrong.

coffeehound

Minrich said:
Yes i am sure that there is one. I will investigate and replace the whole thing.

Since the heater is still working, either the thermostat might just need turning down, or you should be able to replace the thermostat alone.  It's usually a rod shaped thing which does not require draining the tank down to replace, so much easier than replacing the whole heater.