Hot water cylinder temp fix

[noxfort]

1. It's from the bottom compression fitting. Forgot to try ptfe so will do that.

2. It's a Honeywell 3 port. Flow from boiler goes to right (marked A), top inlet for hwc coil goes to left (marked B) and bottom cones from pump with a tee in it for bypass valve.

 

[Madrab]

When reusing fittings, I find it's always best to add a couple of wraps of tape, the olives never sit where they were before so sometimes need that little bit of help to seal back up.

OK then, if it's a 3 port (Y Plan) then it could be the stat isn't shutting the power off to the boiler when the hot water's satisfied. The CH isn't calling too is it?
Needs a circuit tester to check whether it's switching the live off to the boiler.

 

[noxfort]

Quick update.

The valve is no longer leaking. Replaced olive and used a little ptfe all is good.

Checked heating and it clicks boiler on and off and radiators function as should (a few loud knocking sounds sometimes just think it's a little air which i will keep bleeding)

Hot water does turn off but I have it set at 60 degrees and water coming out is almost 80!

Any suggestions?

 

[Madrab]

Where abouts on the cylinder was the stat placed? It should be at around 1/3 of the way up from the base.

Do remember though that the temp of the top of the cylinder will always be a bit hotter than what the stat is set to turn off at, being much lower down.

So expect initial draw off to always be warmer.

 

[noxfort]

The stat sits exactly 1/3 up. Will leave it for a few days and see what happens.

Whilst I had the system drained I cleaned and flushed it. The amount of crappy bits in the water was amazing. My wife keeps complaining the upstairs radiators are to hit now! Guess my next task is to balance it!

Thanks for all the help

 

[john320d]

Suggest you turn your cylinder stat down to 50c which will give 70c approx. 80c will scald.

 

[john320d]

I have ordered a non contact thermometer of the net (amazon) for £10.99.

 

[Madrab]

This is one of the reason that the G3 regs now state, that in all new fit bathrooms and assisted properties a Thermo mixing valve should be installed to ensure hot outlet temp doesn't exceed 48 Deg C, especially to the bath, to avoid a scalding risk.

Hot water cylinders invariably supply water hotter than 60DegC but you need to have most of the cylinder up to at least that min temp to avoid bacteria multiplying, so I'm afraid I have to disagree about dropping the stat to 50Deg

 

[Agile]

I do hope you used a NEW immersion element and made sure it was a incaloy element AND incaloy thermostat pocket!

Tony

 

[Madrab]

Of course, good shout T, stainless and copper elements/pockets don't mix very well.

 

[noxfort]

I used a immersion plug to seal it for now. Even with a box spanner the old one just broke the copper around it. I will order a new thermostat later as its not urgent.

I wouldn't like to turn the thermostat down due to bacteria always been told 60 minimum. I have a thermostatic 3 way shower valve I fitted so bath and shower are set to 38 degrees. Basin is mixer so should be fine.

Guess my next job is to replace the kitchen mixer. its dual flow so you burn and freeze your hands at the same time!

I also took the advice about fitting an adjustable valve to the coil input. Should save me draining if there is a future problem. I also added a drain-cock to the bottom of the cylinder (tee off inlet). There wasn't one on my last cylinder and draining took a while!

 

[john320d]

This is one of the reason that the G3 regs now state, that in all new fit bathrooms and assisted properties a Thermo mixing valve should be installed to ensure hot outlet temp doesn't exceed 48 Deg C, especially to the bath, to avoid a scalding risk.

Hot water cylinders invariably supply water hotter than 60DegC but you need to have most of the cylinder up to at least that min temp to avoid bacteria multiplying, so I'm afraid I have to disagree about dropping the stat to 50Deg [/ Bottom third of cylinder will always be less than 60c. Do not take the stat as being accurate but use it as a guide to adjust the water temp. leaving the cylinder.

 

[Madrab]

If water isn't being drawn off, stored, that's when there is the highest danger of bacteria multiplying, so I understand.
Granted that stats aren't that accurate or responsive but if set to 60degC then, due to convection, that's the better side of the minimum mean temp within the cylinder that's needed to minimise growth.
As the water rises it gets warmer than 60deg, destroying bacteria, as it falls it's mean temp shouldn't fall much below 60deg, minimising multiplication, unless it is being used of course, but that's a different story.
I would prefer that and have a higher outlet temp that I can control with mixing rather than a lower setting and lower mean temp that could increase the risk of bacteria multiplying.