thermostat with contactor problem...help - Tile Advice

[discjockeyr]

Dear All,

I have install an electrical underfloor heating in my new house and i have 2 thermostats that controls 3 zones each thru a contactor. the problem with both thermostats is that when the temperature rich the limit and the thermostats give the commant to contactor to open, immidiately the thermosta restart like something shiort the output of the thermostat and looses the time/date and programming. Did any one came across similar problem?
Thanks in advance

 

[Alan.P]

Sounds like the thermostats are losing their supply, a crossed wire somewhere, can you post a picture of the wiring diagram and the actual control wiring that you have.

 

[pjrich]

Sounds like you need to install a snubber accross the coil of the contactor. If you can advise the manufacturer & part no. of the thermostat(s) we can probably advise what you need to get.

Warm Regards,

Peter

 

[discjockeyr]

first i would like to thanks for your help both of you.
here is a drawing on how is my installation.
The thermostats are XSTAT by warmup

 

[pjrich]

I believe the current warmup xstat is manufactered by a company in Denmark (OJ) and my personal experience is that snubbers are not required with thermostats made by them. If it's an older warmup stat then it may have been made by Aube and in this case a snubber is most likely required.

I've had a look at the instructions for an xstat and it does not mention using a snubber, so I would suggest contacting Warmup to confirm if a snubber is required.

With regard to the wiring, according to the instructions I have for an xstat the connections should be:-

Term 1 - Power Supply - L
Term 2 - Power Supply - N
Term 3&4 - Coil of contactor
Term 7&8 - Floor Sensor
Term 6&7 - Floor Sensor 2 (if used)

Hope this helps.

Warm Regards,

Peter

 

[discjockeyr]

Thanks a lot for your help,

The connections has been made as your instructions. As i know the XSTAT are the latest thermostats that warmup supply but i don't know made of. I will try to contacr warmup hoping to received an answer. Can you tell me what excactly "snubber" is?

 

[pjrich]

A snubber is used to inhibit / reduce transient voltage spikes caused by switching of inductive loads (coil of contactor). It's these voltages that can cause thermostats to reset.

More info on snubbers here:- Snubber - Wikipedia, the free encyclopedia

Warm Regards,

Peter

 

[Uheat]

Great Advice, Thanks

 

[discjockeyr]

Thanks all of you for yours advice.
As is a little difficult to find snubber in my country i have create one. A 0.1μF capacitor in series with a 100Ohms resistor and hope that it will work

 

[Alan.P]

Let us know how you get on

 

[discjockeyr]

Hey there,

SUCCESS... I have made my custom snubber with a 100nF capacitor and a resistor 100 Ohms and the thermostats now working perfectly with the contactor. So, i would like to thanks everybody who advice me regarding this matter. THANKS

 

[pjrich]

Pleased you got it to work, if you ever need electric ufh in the future please contact us and we'll work out a deal for you:hurray:

Warm Regards,

Peter

 

[HowardM]

Contactors are well known for this, you can get hold of a relay that will eliminate the problem and they are smaller. with a contactor the break of the poles is not instant (1 before the other) so will cause feedback from the coil, the snubber is a fix, it is a big capacitor but you can still suffer on the odd occasion the resistor in place helps.

My advice don't use contactors they are big and noisy, get a 32amp relay instead, they fit in a standard back box lifetime similar to that of the thermostat and cheaper.

 

[discjockeyr]

yes, you are correct there is a lot of noice when on/off the contactor. can i find a 3-phase relay din rail to replace the contactors?

 

[HowardM]

Do you mean 3 phase or 3 pole, there are a few 3 pole available but a pain in the preverbial to install as you have to split the load (10 amps per pole), what is your overall load it watts/amps, maybe an easier way to sort it.

Need to know if you really mean 3 phase as this is totally diferent higher voltage higher risk but my guess is 3 pole as your problem is familiar.

Give me an idea of your wiring config I will try to help.