Do I need a tri-port valve?

You need some help attaching the thermostat to your specific boiler. This way please !
Post Reply
Andy T
Posts: 1
Joined: 08 Feb 2016, 15:31

Do I need a tri-port valve?

Post by Andy T » 08 Feb 2016, 15:50


I bought my Netatmo through EDF, who use Help-Link as installers.
When they came to fit it, they told me I must have a 'Tri-port valve' fitted, otherwise the Netatmo won't work.

Currently my system is either on or off controlled by an electric timer.
I have a manual lever in the airing cupboard that has two positions: Hot water only, and Heating and hot water.
When summer comes, I switch it to Hot water only and the boiler is timed to come on twice a day to make sure the hot water tank is full.
This causes me no problems, and I thought I could do the same with the Netatmo, by replacing the old timer.

Can anyone advise whether Help-Link are right? (Their customer service department seem to be utterly useless and unable to return calls.)
Do I need this tri-port valve thingy? What will it do for me?

All help gratefully received.

Posts: 289
Joined: 30 Dec 2014, 21:35

Re: Do I need a tri-port valve?

Post by TypeC » 09 Feb 2016, 14:42

That seems a simplistic explanation (for example, I have 2 two-port valves and that works fine) but it's difficult to say exactly why you were told that from the information you've given. If you don't have any motorised valves, the engineer might have wanted to replace your manual lever with a tri-port and that would probably be a sensible thing to do (although it's a bit of a stretch to say it "won't work" as it is).

You generally can't replace a timer which also works for hot water because the Netatmo has no concept of what sort of control a hot water system needs, nor does it have a physical means of controlling it separately to heating. Typically, an existing timer is left in place and the heating controls are either bypassed or left permanently on to allow the Netatmo to do its thing.

You asked what a tri-port does. It's fairly straightforward: it directs incoming water to one of two different outputs, similar to your manual lever, but only one at once. It is used to direct heated water from the boiler to either a hot water cylinder or the heating system and they operate automatically when a room thermostat or the thermostat you should have in your hot water cylinder tell it they require heat. What it will give you depends on how your system is currently set up, but if you don't currently have a way of directing heated water only where it is needed, efficiency is the most important thing it will give you.

Posts: 18
Joined: 26 Jul 2016, 17:35

Re: Do I need a tri-port valve?

Post by jelockwood » 13 Sep 2016, 12:24

My central heating system which was installed before I got a smart thermostat does have a 'three way valve' aka. tri-port valve. It can therefore either heat the hot water only, the heating only, or both. The boiler also has a programmer which defines the times hot water and heating take place, if both are active and both 'calling for' heat then the valve is told to go to the position for both, if just one is active or calling for heat then it moves to the corresponding position.

I have the programmer set to do heat all the time, and hot water twice a day. In actuality it only does heat if the thermostat calls for heat. Since the thermostat is smart and has its own time programming as well it only calls for heat both when needed and when scheduled.

Before I got a smart thermostat I had a dumb traditional one, and then I had the boiler programmer set to do heat to a normal schedule.

If hot water is not active or called for, and the smart thermostat is also not calling for heat then the boiler shuts down.

The boiler is controlling the valve.

Post Reply

Return to “Attaching the Thermostat to the boiler”