Programmable Room Stat

[rolyatescort]

Further to my previous thread, it would seem that i need to swap my room stat for a programmable one. Problem is my system doesn't have a room stat. how simple is it to add one? Which one(s) should i be looking at?

The system is a Potterton 80 Puma Combi.

Cheers.

 

[breezer]

any room stat will do since you dont have one.(it really depends on what you wnat it to do, some have built in timers, so they also change to max temp for that time of day)

you need to find a wiring diagram of your current wiring* and run a 1mm T & E cable from there to your room stat.


*usually there is a white box some where near the boiler, timer, or pump that has lots of connections in it, it will probably be the same size as a twin socket outlet

 

[PEDANTICVINDICTIVEMAN]

You will need .75mm heat resist cable to wire into or next to the boiler, if it's a combi there may be a terminal strip on the boiler itself with a link to connect to, be careful as you may need a volt free stat, you really need the installation intructions for the boiler before buying and installing the new stat

 

[rolyatescort]

I want it so that i can have a more active control over the system. i have finally got my system so that all the rads actually work but they take forever to heat up. I would like to have the system on at a reduced temp through the day while we are out at work, etc and warmer through the evening and early morning. Also to have a controlled temp as once the system has been at full temp for a couple of hours the house starts to get umconfortable.

I have no external boxes at all that i am aware of. The only wiring is contained in the boiler housing and consists of the on/off, timed/constant and the horrible timer dial.

I do have the original installation plans so i can check those and see what it says on there. What am i looking to connect to?

Thanks.

Edited as i was writing this at the same time as Pedantic was posting, don't want people to think i'm dense for asking what to connect to after Pedantic has already tole me!

 

[PEDANTICVINDICTIVEMAN]

You definately need to look on the wiring diagram for a link in the boiler on it's terminal strip, normally you take the link out and put the room stat circuit in place but as I said you may need a volt free switching stat, the boiler installation instructions should tell you.

 

[bathjobby]

If you ever get there I can recommend this, good function and very flush, only about 10mm. Had one for a couple of years, got excellent service from company too.
http://www.heatmisershop.co.uk/Heatmiser_DT_Standard-p-16133.html

 

[rolyatescort]

that looks good, thanks for that. I have mailed them to check compatability.

Cheers.

 

[felix]

Make that 1mm three core and earth. All the thermostats I've ever seen need a neutral supply for the accelerator heater.

PS: I have some three core flat twin and earth left over from somebody else's two way light switch installation ---

 

[croydoncorgi]

All the thermostats I've ever seen need a neutral supply for the accelerator heater.

Not true.

ALL the battery-operated ones, the radio-linked ones, and MANY other types require two wires only.

Furthermore, many boilers have LOW VOLTAGE controls and if you connect a mains-neutral to the thermostat wiring you will either blow up the boiler PCB or create a potentially-dangerous electrical fault!!!

 

[felix]

Fair point there from Croydoncorgi. I've never bothered with those exotic ones but I did once have a 24 volt bi-metal thermostat. It was essentially identical to its mains cousins except for the gold plated contacts and the much lower value heating resistor. It came in a new house and was wired with three core and earth.

Now this, when I think about it, was bad practice on the part of the builder. I always make a point of not using mains cables in low voltage circuits and vice versa. We even pay through the nose for milti-core cable with a green/yellow core if the stuff has to carry 240 volts. It reduces the chances of somebody making a silly mistake in the future.

So, Rolyatescort, it's three core and earth for mains switching thermostats only. If you're going to use a low voltage one wire it with some other kind of multi-core cable. Avoid anything that even looks like mains cable.

 

[croydoncorgi]

Felix leaps nimbly out of one hole straight into another!

Some boilers have low voltage controls. Others put MAINS voltage on the thermostat connections but STILL need a 'dry contact' thermostat -
AND (obviously) mains-grade cable.

 

[rolyatescort]

Thanks for all that info, i think to be doubly sure i will be asking the manufacturers of both the thermostat and the boiler for their recommended installation criteria.

 

[rolyatescort]

These guys aren't answering my mails any idea whether it is compatible with my boiler?

 

[DarkInferno]

should be... ya.

 

[kevplumb]

terminals 3+4 on the boiler terminal strip and volt free switching