My hot water seems far too hot 🥵

[Deleted member 120897]

Is the cylinder stat located above the heating coil return pipe?, if below it, it will "never" switch off.

No, it’s above it thanks.

 

[Deleted member 120897]

Is the pipe the flow going to the hot water the same temp as the heating aslong as you haven’t had hot water on at the same time as the heating

I didn’t check, didn’t know I was supposed to but I’ll do it next time.

 

[Deleted member 120897]

Is the cylinder stat making good contact with the cylinder? Have you done any electrical testing?

Thanks, I did some a while ago, cylinder stat seems to be making good contact yes, it used to work ok, but it’s now set on 40 but feels a lot hotter, haven’t measured this, but I reckon it would burn without cold mixing.

 

[SJB060685]

If the system originally worked fine then the wiring should be correct. I'd get my multimeter out and do some checks. It's going to be something simple I'm sure.

 

[Deleted member 120897]

If the system originally worked fine then the wiring should be correct. I'd get my multimeter out and do some checks. It's going to be something simple I'm sure.

I’ll be doing that again next, think it was ok though. Shaun has suggested cyl stat is too low, so need to try’s this as well. I did try a Honeywell cyl stat (which was smaller in length), and it seemed the same, so chucked it back in my van.

 

[ShaunCorbs]

Is the bulb fully home should go into the pocket around 4-8”?

 

[SJB060685]

An S plan yes? When the cylinder stat is satisfied it should close the two port and shut down the boiler. Check that that is happening.
If the stat is too low down hotter water will be at the top of the cylinder.

 

[John.g]

Thanks, I did some a while ago, cylinder stat seems to be making good contact yes, it used to work ok, but it’s now set on 40 but feels a lot hotter, haven’t measured this, but I reckon it would burn without cold mixing.

Just to recap, if you turn the stat up the motorized valve opens and if you turn it down it closes.

 

[Deleted member 120897]

Is the bulb fully home should go into the pocket around 4-8”?

Bulb and pocket? It goes into a cut hole in insulation approx depth of 1.5” touching the copper on the cylinder

 

[Deleted member 120897]

An S plan yes? When the cylinder stat is satisfied it should close the two port and shut down the boiler. Check that that is happening.
If the stat is too low down hotter water will be at the top of the cylinder.

Yes s plan, 2 port closes and shuts boiler off. Thank you

 

[Deleted member 120897]

Just to recap, if you turn the stat up the motorized valve opens and if you turn it down it closes.

Yes and yes, thanks.

 

[SJB060685]

So the cylinder stat reaches satisfaction and closes down the valve and shuts off the boiler?
Do you live in a hard water area by any chance?

 

[Deleted member 120897]

So the cylinder stat reaches satisfaction and closes down the valve and shuts off the boiler?
Do you live in a hard water area by any chance?

Yes, the stat is satisfied and turns off. Also 2 port was renewed by myself recently, as originally I thought it might have been the end switch sticking.

Nope, checked this recently with changing my shower valve, it’s soft I believe, comes from Lake Vrnwy in Wales.

 

[SJB060685]

Does sound like the stat shutting down is delayed. A hard water area can cause mass accumulation of limescale within and on the cylinder walls, this would cause the problem you're experiencing.
Could you upload an image of your cylinder so we can see the position of the stat?

 

[Deleted member 120897]

Does sound like the stat shutting down is delayed. A hard water area can cause mass accumulation of limescale within and on the cylinder walls, this would cause the problem you're experiencing.
Could you upload an image of your cylinder so we can see the position of the stat?

Yes no problem , I’ll do it tomorrow when the lighting is better, many thanks so far. Do you think it could still be scale even though I’m soft water area?