Immersion too hot

fredo1664

Hello.

In our (rented) house, the water can be heated either by the oil boiler or by immersion. When we use the immersion, the water is very very hot and it's actually difficult to have a shower. I've attached a picture of the immersion system on our water heater. Does anyone know if with this kind of system we could change the temperature of the water?

Thanks!

cnocbui

Probably yes. Find the circuit breaker for the shower and flip it to off. Undo the screw and lift off that metal cap. Even though the CB is off, I wouldn't touch any of the wires or metal parts you should see under the cap. One of the things revealed should be a rectangular plastic box, possibly with one end slightly pointy, with two wires going into it and with a small plastic screwdriver slotted post with a pointy chevron > on it's side pointing at a numbered scale. This is the thermostat. Normally the max they should be set to is 65°C. Adjust that pointer to point to a lower temperature than it's currently pointing at, reinstall the cap and screw and flip the CB back on.

If the thermostat box feels insecure and wobbles a bit, that's normal, as it's not fixed in by anything more than gravity and the two wires connected to it.

antix80

I'll add something and say, while the water can end up very hot depending on how the thermostat is set it shouldn't matter too much if the shower mixes properly.. Esp the type with one knob for hot/cold, and one for on/off.

If it's anything like mine with two taps in the bathtub connected by a hose to the shower head you're out of luck. You might find it ends up too cold if you reduce thermostat and you're trying to balance the output from the shower head using individual hot and cold taps. That's been my experience anyway.

fredo1664

Thanks @cnocbui , you're a star! It was set to 60°C, so as an experiment I changed to 50°C. That's below legionella requirements if I understand correctly though.

@antix80, thanks, it's a two taps connected by a hose type like yours, that's the challenge! :-(

cnocbui

You are welcome. You didn't mention if this was a recent thing or not, but could the real problem be with the cold water not being cold enough due to being heated by the hot attic space? Storage tanks in attics are such a third world stupid idea.

antix80

60 degrees is scalding hot. 50 is also too hot for a shower. You need to mix in cold water and that's when you end up like goldilocks because it's hard to get the nice temp where it's not too hot or cold.

fredo1664

Yes I mix with cold water. However, at 60°C, even when I fully open the cold water tap, the shower is still quite hot. As @cnocbui said, the problem could be with the cold water not being cold enough (and it's not very cold indeed), but there's little I can do about this (I think... I'm only a tenant in the house). Hence having hot water a little less hot seemed to be my only solution.

The problem could also be that the cold water doesn't "make it" to the shower head, if that makes any sense, because the pressure it's not great in this shower, which is on the first floor at the same level as the hot press. Again probably nothing I can do about that, I already changed the head and the hose.

cnocbui

If the problem is the cold water in the tank being too warm, you could empty and refill it by just running a cold tap for a while before having a shower. The best real fix for low water pressure is a pump, but not a practical consideration when renting. The best upgrade I did to my house was to fit a 3 bar pump so the whole house water system has pressure, except the kitchen cold, which has good pressure because it's fed by the well pump. Makes for lovely showers.

John.G

https://boards.ie/discussion/comment/117627512#Comment_117627512

The shower & hot press (hot water cylinder) on the same level should have nothing to do with your problem especially if the cold water storage tank is well above it, if this is also supplying the cold feed to the hot water cylinder then the flow rate from both should be almost exactly the same when tested separately through the shower head so can't understand why the ""cold water doesn't "make it" to the shower head"".

Outkast_IRE

The problem with these is often the themostat in the immersion has failed . I have seen these boil water before after failing. If turning it down is making no difference then the stat or the full immersion should be replaced , a plumber usually does this.