Thermolec Electric Boiler & Nest Thermostat setup

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Old 07-17-12, 07:47 PM
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Thermolec Electric Boiler & Nest Thermostat setup

greetings All,

I have just finished installing my new electric boiler Thermolec 23Kw and i also got a new Thermostat by NEST.
Before making this choice, i had of course contacted Thermolec and Nest in order to make sure both were compatible with each other.
I used a two wire cable for the thermostat and connected them to C and W1 since all i have is heating. To my surprise, when switching the thermolec up the thermostat didn't switch on as it should.
My test was brief because the water isn't in the entire system but we filled the thermolec just to make sure its elements won't burn out.
I don't know what to do because both thermolec and nest say it should work.
anyone has attempted this and if so, can you please share your method and experience.
many thanks
 
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Old 07-17-12, 08:29 PM
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Try R and W on the thermolec.
Any call be it a heat is made by closing the contact between r (the 24VAC source) and the W (be it W1,W2,W3,etc) as the contactor coil connected to w and c (the 24VAC common or neutral).
The same is true for a fan or cooling call. It always relates to R.
The C is rarely used in a thermostat unless it is there to power it from the appliance transformer
 
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Old 07-17-12, 08:56 PM
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Thank you TOHeating
just to clarify things up, the electric flow chart on thermolec web site appears to detail what connectors should be used. The canadian one has no such information.

the Nest Thermostat has the following connections

RH, W1, Y1, G, C, OB, AUX W2, Rc

the thermolec has

C, W1

You are then asking me to connect as follows

NEST >>>> Thermolec
RH >>>> C
W1 >>>> W1

http://www.epsalesinc.com/thermolecn...let3.30.09.pdf

Nest | Support

many thanks once again!
 
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Old 07-18-12, 06:37 AM
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I believe that thermostat requires a source of power also... most likely is that you need to use a 3 wire setup. IMHO, their website is useless... don't show me a bunch of fancy, showy flash animations, let me download a PDF manual... but what I was able to see is that you do need to power it.

Does it even have a battery?
 
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Old 07-18-12, 04:37 PM
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Yep.

Thermolec C needs to goto the TStat Rh

Nest, interesting stat. Looks like it has a battery and it uses the voltage from r and maybe the load relays in the equiptment. Ie power stealing.
You may find that the Thermolec does not provide enough power to charge the batter due to it's solid state relays.

If that is the case you will likely have to install a 120 to 24 VAC transformer and wire it to the stat also.

Good luck, let us know how things turn out.
 

Last edited by TOHeating; 07-18-12 at 04:53 PM.
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Old 07-19-12, 07:33 AM
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reply from thermolec

in a brief reply sent by a "dino" from thermolec

".....Your plumber is correct, there is no power coming from the C wire. Depending what the NEST needs, you can take 24v from the transformer to feed the thermostat, but C-W1 must remain a dry contact.
Regards, Dino.... "

again, what does dry contact mean and how would i feed 24v from the thermolec transformer to the NEST?

The nest has its own built in battery and according to NEST support, it pulls some power from W1.

am I the only one trying to connect a nest to a thermolec electric boiler ?


 
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Old 07-19-12, 01:14 PM
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am I the only one trying to connect a nest to a thermolec electric boiler ?


Yep, probably.

A dry contact refers to a set of contacts of a switch that do not have their own voltage present on them. A light switch is dry, because you wire 120 on one side and the light bulb to the other, then the other side of the light bulb goes to Neutral.
I think you are going to find that there is some power on w1 and C from the thermolec, as if there is no power from the contacts there needs to be some power on a wire somewhere or nothing would work.
What the thermolec does NOT want is power being applied to either one of the C or W contacts other than what it provides.
Te nest could turn out to be a hornets nest (pun intended) with regards to using with this boiler, or it may work no problem. It's going to be your call if you want to try it though.
 

Last edited by NJT; 07-19-12 at 04:01 PM.
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Old 07-19-12, 04:10 PM
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I wonder if it might not be a good idea to ask EXACTLY what is meant by:

To my surprise, when switching the thermolec up the thermostat didn't switch on as it should.
Did the Nest power up at all and go through the power up diagnostic? Was there a display on it? Did it appear to be functional at all?

Did the boiler simply sit there and do nothing? Tell us what you saw when you powered it.

It is possible that the Thermolec has a PRESSURE safety switch on it. I didn't look closely at that. If you simply filled the boiler and didn't actually pressurize the system, if there's a pressure safety, the boiler of course would not fire.

If you wish to test this theory, aside from looking at the boiler manual to see if this is true, you can always simply apply a jumper wire from the C to the W on the boiler to simulate a thermostat calling for heat. A jumper wire constitutes a 'dry contact'.
 
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Old 07-20-12, 09:11 AM
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Hi NJ Trooper,
sorry for not getting back to you sooner,
it's true that i should have provided more insight when i wrote my initial message.

when i tested it briefly with my plumber, (we did it briefly because we didn't have water in the entire system yet) -we enabled the breaker and i was expecting to see the nest thermostat power on, but it didn't. Then we heard the pump starting and that's where we decided to turn the breaker off. The test lasted about 15 to 20 seconds.

i hope this answers your question.

I'm rather surprised to find out that this has not been tried before (thermolec 23kw + NEST Thermostat)

I'm currently waiting for my plumber to acquire some 5/8 connectors that are in back order before i can conduct other test.

I'm eager to do more testing but i'm afraid to fry my brand new thermolec.

any advise is welcome
 
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Old 07-20-12, 10:14 AM
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I'm rather surprised to find out that this has not been tried before
I wouldn't be that surprised. The Nest is quite new on the market. There is a 'limited' audience here of people that are looking for advice on repairs, etc... I'm sure that SOMEONE, somewhere, has tried this setup. They just aren't here...

The best advice that you could take away from this at this time is to SLOW DOWN! Let the plumber complete the installation and the boiler full and pressurized before you attempt to power up again. You certainly CAN 'fry' the boiler by powering the elements without water FLOWING around them, and it will only take an instant!
 
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Old 07-23-12, 05:53 AM
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If the pump turned on I would say that there was a call for heat being made.
The thermolec is a pretty smart boiler and should protect the elements quite well. Having said that, it would not be very much fun to pop one and have to replace it.
The units actually modulates each element to supply only the power needed to maintain water temp.
MAKE SURE you use the outdoor reset and understand how to set it.
It will save you money, lots of money.
There are a great many threads around here dealing with ODR, and if you can see what you need you can start one. ODR is a subject we seem to like to talk about here
 
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Old 07-23-12, 10:27 AM
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"...The units actually modulates each element to supply only the power needed to maintain water temp.
MAKE SURE you use the outdoor reset and understand how to set it.
It will save you money, lots of money...."


Thanks TOHeating

Actually the outdoor sensor wasn't installed, my plumber said he never installs them and that my thermostat (NEST) would be a good substitute.

In the house i live, i used to feed from my neighbours gaz boiler which has an outside sensor, we didn't save much money and what i disliked about this very feature is that when you've been away for a week and turn your heating on on a moderately cold winter day, the water isn't hot enough and it would take twice as long to heat up my place.

The other problem i have is that I didn't think of running a wire to my roof for this sensor......

 
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Old 07-23-12, 10:02 PM
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Well,
You don't need to goto the roof with the outdoor sensor. North wall is fine.
If you want to have faster response, then you could put in a light switch on the outdoor sensor and open one wire. This will send the boiler to set point, that will get things rocking fast.

You plumber might be a bit out dated, the nest will never adjust your water temp based on outdoor design. if you go to set point all the time then you will fire all your elements to get the water to temperature fast, and to hold it there. Not very efficient.
Sure the rads will heat fast, but they will overshoot and lead to plenty of cycling with large power demands.
Its your money, but it does not take much to run an outdoor sensor and the dividends with be plenty.

Outdoor reset is a well proven system, it's been around for MANY years. Even before fancy electronic controls.
 
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Old 09-07-12, 05:13 PM
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news and advise request

Hey there guys,

i'm back with some news about my set up.

Test went well, there was some air leakage with some connectors but that was quickly fixed. the system was filled and the thermolec powered on... so did the NEST thermostat!!!! (we now know that it only needs two wires)

i first increased the temperature of the thermostat so i can turn the heating on and so it did along with the pump..... sadly, after about a minute, the thermolec and the pump shut down.

I increased the NEST thermostat temperature to 30c but with the same results. the thermolec and pump start and i see on the circuit board of the boiler one led, then two, then third one (led indicate the element that starts to heat) - The heat in the pipe is weak then when it reaches the 3rd element, it shuts down starting by the last element it enabled, then second and first before the thermolec turns off.

My plumber tried to bypass the nest thermostat by short circuiting W1 and C and the thermolec worked wonderfully. 5 leds activated (all 5 elements were fired up) and heat was starting to get noticed. he removed the wire between W1 and C and it continued to work. So i reduced the temperature on the nest and the thermolec along with the pump turned off.

I tried to increase the temperature but we went back to the same odd behavior where the thermolec shuts down after the 3rd element goes on.

I know that the thermolec isn't the blame since a test demonstrated that it worked well and and heat was generated. So, what could it be?

Any ideas guys ? I really need this thing sorted out asap.

many thanks
kr
 
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Old 09-07-12, 06:58 PM
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Get rid of the NEST, it is not properly tested and has been having problems with other system types, use a good old reliable Honeywell. BTW, if you were going to use the NEST for wifi access then you will need to run a third wire to the nest because it must be powered when you turn on the wifi portion of nest otherwise the battery will NOT charge properly. Honeywell now has a wifi thermostat as well. NEST is all hype and has a long way to go IMO.
 
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Old 09-08-12, 08:58 AM
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I'm with hvac on this one... but not because I have any experience with the nest, it is this that you wrote:

I know that the thermolec isn't the blame since a test demonstrated that it worked well and and heat was generated. So, what could it be?
Seems that you've narrowed it down to the thermostat. If it's not the boiler, then that little device out at the end of those two wires HAS to be the culprit, right?
 
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Old 09-08-12, 10:27 AM
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lets not give up yet

Hey Trooper,

Too much time and money has already been spent and i'd like to figure out with hints and help from your experience.

I just spoke with nest support and they guided me through the technical info on the nest thermostat, we found out that the VIN power was around 4.16v which is too low and should be around the 20v mark. This explains why the thermolec shuts down after 1min 17sec (lack of power from thermostat.

Do you have any suggestion on how to boost the power from a small power transformer (e.g. bell transformer) so i can get proper voltage for Vin?

Their certified technicians around where i live charge $85/hr and a minimum of 2hrs is required.

Your help is very appreciated.

regards

Kr
 
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Old 09-08-12, 12:41 PM
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power stealing thermo

one additional question,
i just discovered another of thermolec electric drawing of the circuit board that boiler uses and there's a wee mention that goes this way

Note: If power stealing thermostat is used, thermostat must be powered by separate 24v source and add relay.

If i'm curring using the connection from the thermolec this way

Thermolec >>>> Nest
C >>>> Rh
W1 >>>> W1

If i was to use an external 24v, where should the wires from the transformer go and what's the relay needed for ?

thx
 
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Old 09-09-12, 03:38 PM
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As I said before that thermostat needs to be powered...... you need to power the thermostat using a seperate 24V transformer.

24V hot to RH
24V common to C
W to 24V relay coil
24V common toother side of 24V relay coil
relay common to C from thermolec
relay N.O. to W1 on thermolec
 
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Old 12-25-12, 09:24 AM
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any success?

i have a thermolec 20kw electric boiler for my radiators and also just got a nest version 1.

did you manage to get this working?

thx.
 
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Old 12-25-12, 09:58 AM
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We never heard back from the OP (obviously), but it would seem that the consensus is that you need to hook up a transformer and relay in order to use that 'gadget' with your boiler.

Follow hvactech advice and I think you'll be fine.
 
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Old 12-28-12, 02:46 PM
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nest + thermolec boiler now work together

i have a 20K thermolec water boiler for my home and just made it work with my nest thermostat.

i used to have a battery operated thermostat with the W and Rh wire installed.

i followed the image in this post: http://www.doityourself.com/forum/th...tml#post193298

i used tapped in to the 24 vac transfer (connector 2+3) that is inside the boiler and used this relay from digikey.com Z1053-ND.

that would have been it. but my setup is a bit more complex, since we recently got floor heating for our garage. the plumber installed an extra pump to separately give me circulation control for the garage. so, the thermostat in the garage (a tekmar d508 with in floor temp sensor) was just controlling the new pump.

i ended up installing 4 new relays, to allow each thermostat to turn the thermolec on/off and to turn their respective pumps on/off.

i am attaching a few images to show the wiring and the inside of the boiler.
 
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Old 12-28-12, 05:21 PM
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Thanks Stephan, good info and thanks for sharing!
 
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Old 02-09-13, 07:00 PM
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Smile update

Guys, thanks for the follow up and to all those who helped out.
the nest thermostat connects from the thermolec the way it is shown by the contributors to this thread, the only thing is that the two normal connectors from the thermolec do not convey enough power to keep the nest's internal battery charging. so you need an external AC24v transformer to feed extra 24v in order to keep the nest's battery charged.

I recall some comments made about the nest thermostat that weren't very encouraging, let me tell you, of all the "smart" thermostat I have owned, the nest is by far the best there is out there. it is a truly smart thermostat. I encourage anyone planning on changing their thermostat to get it, it is well worth it and works like a charm with my thermolec 23kw.

cheers
 
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