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Central Heating Integration
elytronic
Posts: 51
We have been avoiding so far to integrate central heating systems.In Europe we have two kinds of HVAC systems in the home: one for cooling which we call the air-conditioning system (see the Mitsubishi system integration thread)and one for heating which we call the central heating system.
The central heating system is powered by electricity or gas or petrol. Most of the systems in my country are petrol powered. The system either consists of visible radiators in each room or it is underfloor based.
The system we have been asked to integrate is an underfloor water based one with zone thermostats in each room. At the beginning, I though this is easy since the thermostats should be dry contacts and we can replace them with communicating Aprilaire (same as AMX or ********) ones. But even if this is the case we must find a way to control the main heating controller and this might not be easy. This controller it usually on a timer and is switched on at different times when needed. It also handles the hot water of the house. Also it seems this controller works based on the outdoor temperature, indoor temperature, boiler temperature and the pipes temperature. Reading more on the subject I found out that these systems are very slow, can be quite complicated and very difficult to integrate.
This is a post from an experienced US integrator discussing this in another forum
:
"Control of convecting heating sources can be simple or very hard. Many systems rely on a circulating pump and this is in essence a digital system--the pump is either on or off-- that any thermostat can control. Others rely on a manifold that has many positions--much like the accelerator in your car and these are almost impossible to control as the thermostats need to behave as analog devices moving the manifold more or less open for more or less water flow. The usual suspects who make automatable thermostats have yet to come out with units designed to control these systems and the thermostats that do control them cannot be automated.
As a side light, there are 2 ways of sensing temperature of radiant floor heat. One is to use a slab sensor and the other to use a sensor, built in to the thermostat or a stand alone sensor, at normal height, say 48-58 inches AFF. Radiant heat is in many respects the most comfortable but it is a slow responding system. It takes time for the heat in the floor to radiate into the room. Slab sensors are great at protecting the system or the floor material but less good at predicting the proper temperature where a person would be comfortable. A sensor mounted normally is better at determining and maintaining a temperature where one is comfortable but will not protect against the system over heating the floor and damaging the floor material"
What worries me are those manifolds and those 3 or 4 way valves that I do not understand how they work.
Please do not advice to leave this on the HVAC contractor and to ask for an interface because this does not work in my country. If I am going to do this I have to know everything about it and be on top of this.
Bear in mind that AMX Europe just send us an update that the new AMX thermostats are not compatible with Europen systems.
I have to find a solution for this. This is a 2000sq.m. home and they are going for a 300k+ AMX system. It would be a shame to leave the heating system out. I am sure some of the advanced European Integrators/Programmers here have done this and they can help us out.
The central heating system is powered by electricity or gas or petrol. Most of the systems in my country are petrol powered. The system either consists of visible radiators in each room or it is underfloor based.
The system we have been asked to integrate is an underfloor water based one with zone thermostats in each room. At the beginning, I though this is easy since the thermostats should be dry contacts and we can replace them with communicating Aprilaire (same as AMX or ********) ones. But even if this is the case we must find a way to control the main heating controller and this might not be easy. This controller it usually on a timer and is switched on at different times when needed. It also handles the hot water of the house. Also it seems this controller works based on the outdoor temperature, indoor temperature, boiler temperature and the pipes temperature. Reading more on the subject I found out that these systems are very slow, can be quite complicated and very difficult to integrate.
This is a post from an experienced US integrator discussing this in another forum
:
"Control of convecting heating sources can be simple or very hard. Many systems rely on a circulating pump and this is in essence a digital system--the pump is either on or off-- that any thermostat can control. Others rely on a manifold that has many positions--much like the accelerator in your car and these are almost impossible to control as the thermostats need to behave as analog devices moving the manifold more or less open for more or less water flow. The usual suspects who make automatable thermostats have yet to come out with units designed to control these systems and the thermostats that do control them cannot be automated.
As a side light, there are 2 ways of sensing temperature of radiant floor heat. One is to use a slab sensor and the other to use a sensor, built in to the thermostat or a stand alone sensor, at normal height, say 48-58 inches AFF. Radiant heat is in many respects the most comfortable but it is a slow responding system. It takes time for the heat in the floor to radiate into the room. Slab sensors are great at protecting the system or the floor material but less good at predicting the proper temperature where a person would be comfortable. A sensor mounted normally is better at determining and maintaining a temperature where one is comfortable but will not protect against the system over heating the floor and damaging the floor material"
What worries me are those manifolds and those 3 or 4 way valves that I do not understand how they work.
Please do not advice to leave this on the HVAC contractor and to ask for an interface because this does not work in my country. If I am going to do this I have to know everything about it and be on top of this.
Bear in mind that AMX Europe just send us an update that the new AMX thermostats are not compatible with Europen systems.
I have to find a solution for this. This is a 2000sq.m. home and they are going for a 300k+ AMX system. It would be a shame to leave the heating system out. I am sure some of the advanced European Integrators/Programmers here have done this and they can help us out.
0
Comments
There is nothing that a HVAC-specific control system can do that you can't program an AMX system to do.
On the assumption that the HVAC contractor has a workable system, the goal would be to find a way to make the AMX system emulate the his system. If you don't understand how his system works, you can't replace it with your own.
The cooling systems are typically 1 or two stage cooling (air conditioning)
We typically install a thermostat that can function just fine on its own but can also communicate via rs-232/422/485 to a control system. So, the control system is essentially monitoring the current values on the T-Stat like current temp, current heat point set, current cool point set, etc... Then the control system simiply 'operates' the T-Stat just as if you were standing right in front of it using your fingers.
we commonly use the Aprilaire 8870. AMX has their own T-Stat that is essentially an Aprilaire 8870 with an AMX logo on it.
This particular T-Stat is configurable so you can set it up to operate most current HVAC systems. There's jumper settings for if it is gas or electric heat, 1 or 2 stage cool, has a humidiier or not, etc...
I'd look and see if this T-Stat will work in your situation. I'd bet it could probably be made to work.