Wood boiler for greenhouse

Heating, insulation, ventilation, VMC, cooling ... short thermal comfort. Insulation, wood energy, heat pumps but also electricity, gas or oil, VMC ... Help in choosing and implementation, problem solving, optimization, tips and tricks ...
dedeleco
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Registration: 16/01/10, 01:19
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by dedeleco » 07/01/11, 23:47

Legrand has a relay
Lexic time relay - flashing
http://www.materielelectrique.com/relai ... -2042.html

Otherwise the eliwell ewpc 902 regulator has its output on SPDT base relay:
http://www.konsonref.com/ProductsFile/EWPC902.pdf
will not be able to control the motor.
Indeed, this regulator has an output with 2 positions, on / off completely incompatible with the 3 states required by the motor of the rotation valve: in the opening direction (T too low), stop (if T is good), rotation in the direction which firm, (T too high).

So even with time delay it will not work !!
At best, this will constantly oscillate between wide open and wide closed, especially since the response time delay will be long, since it will turn all the more lengthily in the same direction excessively.
Above all, you must have these 3 states with that of stopping at good T and slow down the rotation to avoid oscillations.

It is exactly like driving a car with a small electric motor which turns the steering wheel in one direction or the other and controlled by these 3 states: rotation to the right, rest, rotation to the left, (with the advantage that we never leaves the road with T too high momentarily). !!!!!


We can do this easily with electronics (operational amplifiers and NE555) or the simplest possible thermostat that comes out with these 3 states: T too low, T good, too high !!!
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dedeleco
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Registration: 16/01/10, 01:19
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by dedeleco » 08/01/11, 00:13

If your 3 "66-point control 3-way valve actuator looks like this:
http://www.heimeier.com/be-fr/PDF/Info_ ... 3.1-lq.pdf
the 3 points are the 3 necessary states ?????????????????????

Pay close attention to the voltages driving this motor:
24V and
0–10 V; 10–0 V; 2–10 V;
10–2 V (direct current) ????????
otherwise he is dead !!
You have the HEIMEIER E1 thermostat that works with it and it's the simplest.
I ignore the price.

The actuators and solenoid valves are varied and therefore read the precise instructions !!
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dedeleco
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by dedeleco » 08/01/11, 13:56

Otherwise, without electronics, simply, you can generate the 3 points or states with two basic bulb or other thermostats and two 12V relays controlling the servomotor and its power supply.
On the first, the contactor connects via a relay the power supply to the direction of rotation of the valve motor (depending on too hot or too cold) and thehe third point of rest is obtained with the second thermostat set at a temperature slightly different from 3 or 4 ° C (a little more than the hysteresis).
When this second thermostat is in an opposite state to that of the first thermostat, it indicates that T is good close to the good value and therefore it is used for cut off the motor supply of the valve via a second relay which cuts off the supply current to the actuator. This relay is activated to cut the supply by its coil connected between the two outputs with opposite voltages of the two thermostats if T is good and leaves the supply voltage if the two thermostats are in the same voltage state, then with no current in this second relay.

Finally an old flashing light slowed down to the cooling of its bimetallic strip ensures the rotation of the servomotor, by small very spaced movements.
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dedeleco
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by dedeleco » 08/01/11, 18:41

Otherwise we sell assembled or not in thermostats kit all facts and timers or timers, very simple which can be used to make a cheap controller by modifying the thermostat a little to put the breakpoint using the unused pieces of triple operational amplifier of the integrated circuit, to control and perform stop at the position at the right temperature.
http://www.conrad.fr/thermostat_p_48674 ... 212475_FAS
http://www.conrad.fr/kit_minuterie_p_48 ... 207834_FAS

http://www.conrad.fr/kits_de_temporisat ... 9290_49292
http://www.conrad.fr/kits_de_thermometr ... 9271_49273

By searching we can find other Kits on selectronic, etc.

http://www.jlelectroniq.com/mounel/sono ... fAodW3fYjg

http://www.jlelectroniq.com/fich2vel.as ... 49&clef=IO
http://www.selectronic.fr/soussousfamil ... fam_ref=50
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antoine35
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posts: 20
Registration: 08/12/10, 22:17




by antoine35 » 10/01/11, 17:57

Otherwise the eliwell ewpc 902 regulator has its output on SPDT base relay:
http://www.konsonref.com/ProductsFile/EWPC902.pdf
will not be able to control the motor.
Indeed, this regulator has an output with 2 positions, on / off completely incompatible with the 3 states required by the motor of the rotation valve: in the opening direction (T too low), stop (if T is good), rotation in the direction which firm, (T too high).

So even with time delay it will not work !!
At best, this will oscillate without stopping between wide open and wide closed, especially since the response delay will be long, since it will turn all the more lengthily in the same direction in an excessive way.
Above all, you must have these 3 states with that of stopping at good T and slow down the rotation to avoid oscillations.

It is exactly like driving a car with a small electric motor which turns the steering wheel in one direction or the other and controlled by these 3 states: rotation to the right, rest, rotation to the left, (with the advantage that we never leaves the road with T too high momentarily). !!!!!


We can do this easily with electronics (operational amplifiers and NE555) or the simplest possible thermostat that comes out with these 3 states: T too low, T good, too high !!!




Thank you for all the info!
when you say that it will not work with the ewpc902 but that it will work with 2 thermostats adjust differently, I think I understand but did not you homis that the ewpc 902 can have an adjustable hysteresis, which will come back a little to even or so I did not understand and in which case I will not tinker with a system but will charge the regul to my colleague (too bad for him) because despite your great info, me, the electronic amplifiers and everything, that makes 2.

otherwise I am still a bit annoying regarding the pressure losses for the calculation of the emitter side circulator. the floor is 20m by 9m, at each end there is a diameter 50 nurse over the full width and they are connected by a pipe of 25 every 30cm (kind of giant towel dryer).
how can i calculate all this?
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dedeleco
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by dedeleco » 10/01/11, 18:47

The ewpc 902 only has a 2-state output: heating, or nothing = cool, and not a 3-state output: operation before opening the valve, resting at the correct T, closing backward !!
The hysteresis regulates the difference of T between stopping at too hot and reheating if too cold, either in fact the duration and the rate of heating on and off, which has nothing to do with the nature of the output or for heating by 2 states: on off or 3 states for solenoid valve !!!

Otherwise, even with the regulator with the language of heating specialists sometimes unclear, beware that you have the right regulator that meets your needs and your solenoid valve !!!!
Be hyperméfiant, in any case, I know that it is easy to be mistaken with the professionals who think by habit, with their vocabulary, and not always by understanding a different situation well !!
Also, make the big effort to understand, even the electronics that fill this kind of regulator for precise specifications that can play ugly tricks !!
Otherwise you risk going wrong and buying several regulators before the good !!!
Installation with 2 thermostats and relays is simple and inexpensive, and can be improved if necessary.

Otherwise if I understand, you have 9x3 = 27 pipes of 25 of 20m long in parallel, which has a low pressure drop with parallel pipes, the pressure drop of an insulated pipe at given flow rate in this single pipe , is that of this pipe alone, identical for all 27, and the total flow is 27 times greater, and the pressure drop for flow given in the total is therefore 27 times less !!
So the pressure drop is low, probably that of the inlet and return pipes of 50 if they are long?
A conventional circulator may suffice, provided that its flow rate with low load is capable of removing heat from the boiler, for the difference in T between return and return that you desire.
See the charts of pressure drops which I had copied elsewhere on econology for a problem boiler.
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antoine35
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posts: 20
Registration: 08/12/10, 22:17




by antoine35 » 30/01/11, 18:46

here I am again, being under construction I wonder what exactly is the famous thermal safety valve.
I can't get confirmation as to its installation and its operating principle.
I found documents which explain that this valve is used in case of temperature reaching 95 ° c to send cold water in the circuit to cool it and I find explanations which explains that if this temperature is reached it opens letting the water escape and therefore the excess pressure.
in the first case it must be connected to the water network and in the second case to the sewer.
the assembly is therefore not the same ..... what do you say?
at the same time I will install an overflow expansion vessel; is this valve still necessary?
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dedeleco
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by dedeleco » 30/01/11, 19:23

Both are good and useful but apply to two different elements of the boiler and its hot water tank (often sanitary)!

1) on the hot water circuit heated directly by the boiler, safety valve for overpressure often at 3 Bars, and which operates when the expansion tank is dead, causing water to lose from the boiler, indicating that it change the expansion tank or re-inflate it with a car wheel pump. .

2) on the hot water tank, on the expanding sanitary water, a pressure relief valve is mounted to evacuate the excess dilated water, often in a single element, coupled with the inlet tap d cold and purging water, connected to the sewer or drain !! this set is well spread and stuck.

So very different on 2 different circuits that never meet !!
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antoine35
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posts: 20
Registration: 08/12/10, 22:17




by antoine35 » 31/01/11, 13:06

ok I understand but are you talking to me about the "prescomano" type valve?
I am talking about a thermal safety valve (supplier name) which consists of a screw body and a bulb to be planted in the balloon or the boiler and which hangs according to a temperature and not a pressure.
where from my question is it necessary insofar as I put an open expansion tank?
more I follow your advice by connecting the DHW circuit on the buffer tank since the boiler is only used for heating so the 2 circuits will meet in the buffer. in this regard can I simply connect (2 pipes without even a circulator ) the DHW circuit on my buffer tank since they will be subject to the same network.?
hoping to be clear in my words ...... thank you for all this advice.
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dedeleco
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by dedeleco » 31/01/11, 14:33

I can hardly see clearly!
The only way to be clear and to avoid misunderstandings is to detail as much as possible: details of the devices, references on the internet, model, manufacturer, diagrams, precise and detailed sentences, otherwise we understand it wrong with misunderstandings !!

So as far as I can guess ??
1) the expansion tank opened at the highest does not provide security near the boiler, because a rapid and violent overpressure takes time to propagate to the balloon, and by inertia can cause farting.
So considering the price, it is safer to put a safety valve very close to the boiler heat source which can boil water quickly (depending on its mass).
2) for the greenhouse is there domestic water ??
Or is it just the water that heats the greenhouse in the ground?
Normally the water circuit of the boiler is never connected to sanitary water, because otherwise we drink rot from the boiler and radiators !!
So a diagram would be useful to see clearly.
On econology, there are posts on the problems of boilers, cylinders and radiators with circulator which do not always work well (pressure losses) !!

The heating in the ground could serve as a buffer without a balloon, if it is large enough, and therefore it is necessary to evaluate its real mass (20cm to 50cm of earth around the pipes) !!

I invite you to thoroughly explore with rigor and diagrams to avoid difficulties once mounted.
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