Hot Water not enabling while central heating running

NGEh · 6 Feb 2021

Hello,

Nest 3rd Gen, Hot Water cylinder, British Gas 330 rebadged Glowworm, Drayton MA1 3 way actuator and Drayton HTS3.

If both CH and HW off, Actuator sits in middle position .

Central heating turns off and on absolutely fine, manually controlling and scheduling via Nest, moving to H position.

If the CH is ON and HOT WATER is called either manually or via the Nest schedule, the Actuator will remain on H. switching the CH off results in the actual moving to W.

Manually calling the HW when off will move to W and heat the HW.

If I turn the HTS3 right down to OFF, the actuator click and will move away from W. I am wondering if everything is behaving normally as I am sure it used to start to heat the water when scheduled
And the CH was on.

One thing I have noticed is that the HW can be absolutely roasting and it doesn’t seem to do anything to stop heating the water.

Thanks for any help.

MeldrewsMate · 6 Feb 2021

It appears to have been mis-wired.
Is the Nest newly installed?
Which port (port letter cast into the 3-port valve body) goes to the hot water cylinder?

As always, some photos would answer many questions of this type.

ianmcd · 6 Feb 2021

sounds like you havent wired the HW off wire and the satisfied wire from the cyl stat in properly

NGEh · 6 Feb 2021

MeldrewsMate said:
It appears to have been mis-wired.
Is the Nest newly installed?
Which port (port letter cast into the 3-port valve body) goes to the hot water cylinder?

As always, some photos would answer many questions of this type.

The Nest was installed about 4 - 5 years ago by an “electrician” arranged by First Utility. He brought his “tools” in a single use Tesco carrier bag. Demonstrated the system “working” and then left. I realized later that the heating and hot water were wired back to front. After trying to get a return visit to sort it out, I ended up correcting it in such a way that it worked correctly to give us heat and hot water but to be honest, we have tended to demand the hot water as have hardly been in the house during previous years when it would need to be on a schedule like we need it now.

I can tell you that the wiring box beside the hot water cylinder and actuator has the following cables connected:

# / ACTUATOR CABLE / HTS3 CABLE
2 / BLUE / -
5 / WHITE / -
6 / - / BROWN
7 / ORANGE / BLACK
8 / GREY / BLUE

NGEh · 6 Feb 2021

Here’s a picture of the Nest Heat Link

ianmcd · 6 Feb 2021

you will have a wiring centre probably what the motorised valve wires into, can you post a pic of the wiring in there

NGEh · 7 Feb 2021

Do these help?

Agile · 7 Feb 2021

Wow! That will engage Ian.

If he was at your place then he might suddenly get a call to say his wife was having a baby and he had to rush off!

Others might post a photo of what a proper Wiring Center looks like!

NGEh · 7 Feb 2021

I hope so...! This is how I believe the installation has been since the house was built... we have had it for about 7 years.

it’s an ex showhouse from the 90s but you wouldn’t think it with the amount of things I’ve had to sort out. I believe the boiler itself was replaced in 2010.

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Hot Water not enabling while central heating running

NGEh

MeldrewsMate

ianmcd

NGEh

NGEh

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ianmcd

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Agile

NGEh

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