Tempest heat pump water storage tank Aquastat ?

[Cyberfruits]

Hi I am hoping somebody can confirm that this is a Aquastat on my Tempest heat pump water storage tank and if it is not what is it? Does it control the hot water?

Also as it is not straight but slightly bent should I straighten it, can I straighten it by removing the screw?

[ProDave]

That is certainly a water thermostat.  It is a bulb on the end of a capilliary tube that slides into a thermostat pocket in the cylinder.  the grey plastic cover contains the actual thermostat and the fact it is slightly wonky is of no consequence.

 

That looks quite low down for the normal thermostat position, I assume there is an alternative thermostat pocket nearer the mid height of the ctlinder?

 

If you are heating it with an ASHP there is very often a temperature sensor supplied with the ASHP as well.

[Cyberfruits]

54 minutes ago, ProDave said:

That is certainly a water thermostat.  It is a bulb on the end of a capilliary tube that slides into a thermostat pocket in the cylinder.  the grey plastic cover contains the actual thermostat and the fact it is slightly wonky is of no consequence.

 

That looks quite low down for the normal thermostat position, I assume there is an alternative thermostat pocket nearer the mid height of the ctlinder?

 

If you are heating it with an ASHP there is very often a temperature sensor supplied with the ASHP as well.

It is actually up quite high I think, just an illusion of the pictures.

Is it all one unit the bulb andthe end of a capilliary tube?

[Jenki]

23 minutes ago, Cyberfruits said:

Is it all one unit the bulb andthe end of a capilliary tube?

Yes. Undo to small screw and it all slides out, mine also has the probe the ASHP sat snuggled in with them as @ProDave mentioned 

[ProDave]

In my case I have the ASHP probe in the centre thermostat pocket and the mechanical thermostat in the upper pocket.

 

The mechanical thermostat is only there in my case to satisfy the G3 regs of an unvented cylinder, to close the motorised valve feeding the UVC in the event of it over heating.  But since it is impossible for an ASHP to heat the water hot enough to worry an UVC it is a theoretical possiblility and I never expect it to operate.  But rules are rules, it has to be there.

 

@Cyberfruits that link in your post above asks me to sign into google drive or something like that, I suspect that is not what you wanted to post.

[Cyberfruits]

1 hour ago, ProDave said:

that link in your post above asks me to sign into google drive or something like that, I suspect that is not what you wanted to post.

Strange i did not post a link just a picture.

[HughF]

On 29/03/2024 at 15:06, ProDave said:

In my case I have the ASHP probe in the centre thermostat pocket and the mechanical thermostat in the upper pocket.

 

The mechanical thermostat is only there in my case to satisfy the G3 regs of an unvented cylinder, to close the motorised valve feeding the UVC in the event of it over heating.  But since it is impossible for an ASHP to heat the water hot enough to worry an UVC it is a theoretical possiblility and I never expect it to operate.  But rules are rules, it has to be there.

 

@Cyberfruits that link in your post above asks me to sign into google drive or something like that, I suspect that is not what you wanted to post.

Show me a pre-plumbed heat pump cylinder than has a hi-limit stat wired to the 3 port and I’ll show you a unicorn.

 

 

Edited March 31 by HughF

[JohnMo]

7 minutes ago, HughF said:

heat pump cylinder than has a hi-limit stat wired to the 3 port

But most cylinder thermostats are dual thermostats so no additional wiring is required.

 

But that is only applicable to a heat pump or X plan with a 3 port diverter. If it's a mid point valve an additional 2 port is also required to protect the cylinder - a self closing 2 port.

[HughF]

1 hour ago, JohnMo said:

But most cylinder thermostats are dual thermostats so no additional wiring is required.

 

But that is only applicable to a heat pump or X plan with a 3 port diverter. If it's a mid point valve an additional 2 port is also required to protect the cylinder - a self closing 2 port.

I’m not arguing you can’t do it, I’m arguing that no-one does (as it’s unnecessary imho).

 

My Vaillant certainly doesn’t have it wired up thus…

[ProDave]

6 minutes ago, HughF said:

I’m not arguing you can’t do it, I’m arguing that no-one does (as it’s unnecessary imho).

 

My Vaillant certainly doesn’t have it wired up thus…

Well I did it on mine and on every cylinder I have wired.  NOBODY should be using a 3 port mid position valve, the work of the devil.  2 or more 2 port valves for me always.

 

I wired the hi limit stat in mine because that is what you are supposed to do, and one less thing for BC to find to fail it if they are looking hard enough.

 

Just because a lot of people don't bother is not reason to copy them.

[HughF]

Yes, 3 port mid position valves are pure evil. 
 

However, Pretty much every single pre-plumbed heat pump cylinder from all the major suppliers use a 3 port diverter.

[Jenki]

18 hours ago, HughF said:

Yes, 3 port mid position valves are pure evil. 
 

However, Pretty much every single pre-plumbed heat pump cylinder from all the major suppliers use a 3 port diverter.

I took the 3 port off mine, wired in two 2 Ports and connected the high limit stat in series to  the Samsung  control panel.  Rules are rules