Honeywell St9400S Boiler

[JuniperEccles]

I've recently had an 'upgraded' programmer installed and the electrician set the heat of the hot water before he went on to show me how to use the rest of the controls. I'm finding the water isn't as hot as I'd like it but I can't find where he set the temperature. Can anyone enlighten me, please?

[klazomaniac]

Hi juniper. There will be a little box on your hot water cylinder (possibly in the airing cupboard)with a wheel on it to alter the hot water temperature.

[klazomaniac]

It will look something like this

https://www.plumbworld.co.uk/honeywell-home-l641a-cylinder-761-1359

[The Builder]

What's the make & model number of the boiler Juniper?

[JuniperEccles]

Many thanks, klazomaniac. I found a dial in the hot water cylinder set at 50 so I moved it round to 60 and it whirred a bit but it didn't blow up so I'm hoping that's sorted it.

The Builder: It's a Honeywell ST9400S, as in the question heading!

[The Builder]

No, Juniper............. that's the controller, not the boiler ;o(

[The Builder]

The reason I ask is that increasing the setting on the cylinder stat only affects the temperature at which the boiler comes in to heat up the water.

e.g. you can set it to 60, but, if the boiler is set to only 50, then it will never get there.

I guess you are talking about boiler-heated hot water, and not immersion cylinder heated water?
For immersion (electric) water, you would increase the temperature setting on the heating element itself.

[klazomaniac]

The Whir noise came about as you have demanded an extra 10 degrees C (The boiler and pump have kicked in)

Gas safe members and Electricians are told by governing bodies to set the Temp at 50 degrees ( Because if you scold yourself, They are liable)
So it is then up to you to set the limit to your needs. Thus relinquishing the installer of any comeback.

I have found that 60 - 62 degrees is a good setting. But please be careful using you hot water for a few days (as the system temps can fluctuate a little after being altered.

Glad you got sorted.

[JuniperEccles]

Sorry I was facetious, The Builder! The name on the boiler is Potterton Promax SL - is this what you were asking for?

[The Builder]

Don't give it a thought Juniper ;o)
Looking through the boiler manual, I can see that it's different from a lot of others in that it does not have a facility to set the hot water temperature actually on the boiler itself. It has to be done from the Honeywell controller.
I see what your electrician was doing now.

Reading the Honeywell user guide was no help at all. All it says is that, on boiler installation, the HW temp. is set at 55-60 degrees.
I'm sure there must be a way to change it, but it's not obvious.

Klaz's adjustment may well be all you need. Let's hope so.
Meanwhile, I would suggest you either contact the electrician to get him to tell you how to adjust the temp. or contact Honeywell Technical help.
033 130 1299 option 1

https://heatingcontrols.honeywellhome.com/news/Technical-Desk-Open-For-Business

:o)

[JuniperEccles]

Having found the dial on the cylinder I turned it to 60 and the water is indeed hotter so thank you both for your time and trouble.