How to install a RAVI or Tapstat to control HW cylinder water temperature.

[Don123]

Hi All,
New to the forum and only have basic plumbing knowledge so here goes on my first post.

I currently have no temp control on my HW cylinder and was thinking of installing a RAVI or Tapstat type mechanical thermostatic control valve.At the moment,HW cylinder temp is being crudely controlled via the Boiler stat setting.My CH system is fully vented with a motorized zone valve for HW or HW&CH.

Question 1 - Do I need to fit a 3 port valve/RAVI to include a bypass route if the valve is ever fully closed ? If so can I use existing return of HW cylinder coil?

Question 2 - Can a 2 port inline valve alternately be used in this type of installation and if so, how does that work if no bypass present?

Question 3 - Is whatever type of valve used connected directly across the HW cylinder coil?

Any help and advice with these questions would be greatly appreciated in my attempt to control my domestic HW temp.

Cheers & thanks,
Don123

 

[stevetheplumber]

3 port always open in o0ne direction so9 no bypass needed two ports shut totally so yes bypass needed

 

[Don123]

3 port always open in o0ne direction so9 no bypass needed two ports shut totally so yes bypass needed

Hi Steve,
Thanks for the feedback.Need to excuse my limited plumbing knowledge, but still not quite sure what you mean.Should I fit a 3 port valve/RAVI between the HW cylinder coil flow and return so if valves closes, water would only circulate back through coil return and not enter coil and keep circulating in this circuit until boiler stat shuts down? Also can I use the coil return rather than running a return seperately back to the boiler?Thanks again.

Don123

 

[doitmyself]

My CH system is fully vented with a motorized zone valve for HW or HW&CH.

Which make/model valve is that?. Where, in the pipe work, is it situated?

A pic would be helpful.

 

[Don123]

Which make/model valve is that?. Where, in the pipe work, is it situated?

A pic would be helpful.

Hi doitmyself,
I have not yet purchased or fitted a RAVI or Tapstat yet until I know exactly which type to get and the correct method and where to install it.As it stands currently,it is just a standard HW cylinder coil that is in place with no form of temp control.Thanks.

Don123.

 

[AWheating]

What type of system do you have? Whatever you fit will need to talk to the boiler to tell it to turn off.

 

[ambrosia]

Don123 if you only have limited knowledge youre taking on a lot, youre going to have to fit zone valves, either a Y plan or S plan controls
Hot Water Only

post some pictures or a diagram of what you want done and i'm sure people will offer advice, but its not a small job

Tapstats go on the return but there are far better ways to control your hot water and as AWheating rightly said they wont talk to the boiler (or pump) and tell them to turn off

I have no idea what a RAVI is

 

[doitmyself]

I have not yet purchased or fitted a RAVI or Tapstat yet until I know exactly which type to get and the correct method and where to install it.As it stands currently,it is just a standard HW cylinder coil that is in place with no form of temp control.

I realize that you have not purchased a RAVI/Tapstat, but I was not referring to them.

In you OP you said (2nd para):

My CH system is fully vented with a motorized zone valve for HW or HW&CH.

I want to know the make/model no of the motorized valve and where it is located in the pipework. A pic would also be very helpful.

You may not need a RAVI/Tapstat

 

[WHPES]

If you have a motorised valve already, you need a cylinder thermostat on Y plan to control the hot water temperature, not a RAVI.

Without more info, we can't advise. You are best to speak to a professional as its really beyond the scope of basic DIY