incorporating heating controls into daikin a/c

[rbartlett]

hi guy's

a customer wants to be able to turn the rad's off when the a/c is on and vice versa (it's a vrvII) . we asked daikin if there is such a beast but they said no.

we have said we would need the full bms screen thingy ma bob and that we feel that we can incorporate some kind of control ..

anyone done this-or similar??

cheers

richard

[Karl Hofmann]

I've not needed to do anything like this, but I'm sure that it would not be a problem to use a relay that opens when the ac is running and incorperate this in to the heating systems room stat, thus fooling the heating system in to thinking that the set point has been reached, but leaving the system on to provide hot water for washing (Assuming that the water is heated off the same boiler / s.

How are the rads heated? Banks of domestic gas or oil boilers? is the premesis divided up in to zones controlled by several room stats or just one stat with TRVs on the rads?

[eggs]

i,ve just got in from the pub!!! so forgive me.

BUT.....

if you put themostatic valves on the rads, will they not turn the rads off if the room temp requires it to?????

if not,

tell the customer they have been ripped off, the central heating system they have bought is not up to the job. They really want to invest in heatpump technology etc...etc...

just my "strongbowed" thoughts on first principles.

cheers

eggs

[rbartlett]

i don't know an awlful lot abut this one..just the customer doesn't want the heating to fight the a/c etc

i think he wants each room to have some kind of sol valve which isolates the rad when the a/c is switched on..

cheers

richard

[Temprite]

G'day Richard.

What if you put a relay into the power supply for the indoor units that opens when you turn the rads on.

When the rads are turned back on indoor units do an auto restart and go back to the previous settings.

Outdoor is still energised so oil is still heated in compressor.

Have done this on a few high walls where customer didn't want remote left in residence (commision house)

Also on holiday rental timed switch turned off power to indoor after 2 hours of use so that people wouldnt leave a/c running when they left premises.

Had a customer that had a super multi plus installed and had a management system in his house. He was going to put relays inline with all indoor units.

Regards

[Karl Hofmann]

Eggs,

If you relied on rad valves, the heating would fight with the ac.

You will have one of three systems,

1. Two pumps, one pumps the hot water circuit, the other pumps the heating, each is controlled by a stat that turns the pump on and off depending on temperature, a relay to open the CH circuit supply from the stat and turn off the pump when the ac system is working.

2. One pump that feeds a three way motorised valve that feeds either the Domestic hot water, Central heating or both depending on the demand from the stat on the water tank nand the demand from the room stat. A relay to interupt the room stat will do the job.

3. A combi boiler, which has a bridge on the connector terminals which will still be in there if there is no room stat, or will have the room stat connected to the boiler, interrupt the supply to or from the stat with the relay.

All straight forward stuff if you can make a relay that will open when the ac is running / switched on and close when it is off.

[Peter_1]

The normal thermostatic knobs can be replaced with a cheap electrical controlled knob.
We've done it some times where we installed a Hp and as soon the 4 way valve was energized, we energized also the electrical knobs on the radiators.
We had to do this because we had a small cooling load and a relative big heating load.
We didn't want to size the AC for heating because it should then too big to cool the room.
We also installed at least 5 systems where we installed a ducted Mitsubishi (PEHD) indoor but used a cooling only outdoor.The control for the 4 way-valve was used then to energize a 3-way water-valve.
This valve was mounted on a standard warm water-coil which was installed between the central discharge duct, just after the indoor unit.
The warm water was delivered by the central water heating system which was already installed in the building.
This was possible with the older R22 units because the indoor unit was giving a 12VDC signal to the 4 way valve. These days, the controls are given via the power wires and this has become more difficult.
There must be somewhere a connection on the PCB that gives a signal as soon the unit is running in heating mode. You still have the 4way valve which is 220VAC energized.

[bernard]

Hi Richard

A few years back the company I worked for took on a job that required special controls.From what I remember Daikin could not meet the requirements,in the end SWM sold us some Hittachi A/C and put us in touch with there technical department and a controls company.

I fitted the Control panel and the technical department talked me through the conections to their A/C system.

The controls are different to what you require but I,m sure if you explained your needs they would come up with a solution.Hope this helps,I can never remember whether you are pro Hittachi or not

Regards Bernard

[Cofreth]

Sorry..,what is rads &TRVs stands for?

[Karl Hofmann]

My apologies,

Rads are radiators, In the UK it is the most common form of domestic heating. They are filled with water heated by means of a gas or oil fired boiler.

TRV stands for Thermostatic Radiator Valve, These simple mechanical valves close off the water supply to the radiator when the room temperature reaches a set value

[Cofreth]

My apologies,

Rads are radiators, In the UK it is the most common form of domestic heating. They are filled with water heated by means of a gas or oil fired boiler.

TRV stands for Thermostatic Radiator Valve, These simple mechanical valves close off the water supply to the radiator when the room temperature reaches a set value

Thanks Karl for the explanation, in Singapore we don't have any four seasons here except three only, hot,hotter & hottest... :-)

[eve walt]

Hi Richard easiest way ,just use a heating/cooling thermostat with a dead band which should stop each system fighting each other

[rbartlett]

Hi Richard easiest way ,just use a heating/cooling thermostat with a dead band which should stop each system fighting each other

so how would you incorporate this into a central heating system with individually controlled radiators and a Daikin vrvII ?

cheers

richard

[Cofreth]

How about using a two way or 3 way spring return on/off motorized valve being interlock through a relay with the VRV fan coil unit blower motor supply?
When the VRV fan coil is turn 'ON', the fan motor supply will energize the relay to turn 'OFF' the motorized valve, thus stopping the flow of hot water supplying to the radiator.

Correct me if I'm wrong.

[rbartlett]

How about using a two way or 3 way spring return on/off motorized valve being interlock through a relay with the VRV fan coil unit blower motor supply?
When the VRV fan coil is turn 'ON', the fan motor supply will energize the relay to turn 'OFF' the motorized valve, thus stopping the flow of hot water supplying to the radiator.

Correct me if I'm wrong.

but if you want to run the vrv in heating the radiators will shut off ....


cheers

richard

[Cofreth]

but if you want to run the vrv in heating the radiators will shut off ....


cheers

richard

Sorry..Richard,
I'm abit confuse here,
Anything the VRV system heating mode related to the radiator?

Thanks,
Steven

[rbartlett]

the vrv is a heatpump and cooling system.

the radiators are heat only

therefore you would only want to control the vrv cooling side as it 'may' fight the radiators.

but when the vrv is on heating you would still want the radiators to be allowed to work as normal

a simple 'fan coil on/radiators off' type control will prevent the radiators working if the fan coils is in 'cool' 'heat' or 'fan only'.

ie : if the customer want to circulate the room air on 'fan only' he can't have any radiator heating!

so this is not the solution we need as it limits the radiators too much


...................heating..................fan only..........cooling

vrv...............on...........................on....................on
radiators.......on...........................on.....................off



cheers

richard

[Cofreth]

the vrv is a heatpump and cooling system.

the radiators are heat only

therefore you would only want to control the vrv cooling side as it 'may' fight the radiators.

but when the vrv is on heating you would still want the radiators to be allowed to work as normal

a simple 'fan coil on/radiators off' type control will prevent the radiators working if the fan coils is in 'cool' 'heat' or 'fan only'.

ie : if the customer want to circulate the room air on 'fan only' he can't have any radiator heating!

so this is not the solution we need as it limits the radiators too much


...................heating..................fan only..........cooling

vrv...............on...........................on....................on
radiators.......on...........................on.....................off



cheers

richard

Richard,
How about install an additional thermostat in the air duct in series with your radiator?
When the air is cold,while in 'cool' mode, it stops the radiator flow.
So when in 'Heat' or 'Fan' mode, it allows the radiator flow.
You may have another room thermostat to control the radiator flow too.
Then this two thermostat will be in series.

Hope this help.

[rbartlett]

what happens when the a/c cycles? the in/out air become simular and the stat 'makes' and the radiator valve opens

cheers

richard

[Cofreth]

what happens when the a/c cycles? the in/out air become simular and the stat 'makes' and the radiator valve opens

cheers

richard

Was wondering under what circumstances you will need to run the air-con in 'cool' mode along with the heating radiator? :confused: :confused:

[rbartlett]

Was wondering under what circumstances you will need to run the air-con in 'cool' mode along with the heating radiator? :confused: :confused:

under no circumstances -which is why the owner wants it locked out!!!

which is why i posted this -


...................heating..................fan only..........cooling

vrv...............on...........................on....................on
radiators.......on...........................on.....................off

cheers

richard

[Cofreth]

under no circumstances -which is why the owner wants it locked out!!!

which is why i posted this -


...................heating..................fan only..........cooling

vrv...............on...........................on....................on
radiators.......on...........................on.....................off

cheers

richard

I'm not too familiar with the VRV circuit, since it is a heat pump model, do you have a reversing valve installed in the condensing unit?

[rbartlett]

my thoughts have naturally drifted towards utilising the control aspects of an aspen universal pump which could also (if necessary as I don't know if pumps are needed) control the water valve.

this is a simple two sensor with a 5 minute time override.

if blue sensor is 5 degrees below red sensor then a switch is activated (usually the peristaltic pump of course)

it also has a run on timer of five minutes which would overcome the a/c cycling issue..

i will ask aspen if they are willing to sell me the electronics with sensors or if i have to dump the pumps (if not req'd) and just use the gubbins..

I personally would prefer a proper daikin type accessory but it appears they only 'do' a whole system lock out board -KRP 2A1. And whilst this would indeed lock out the heating completely I fear the customer wants individual room control..

cheers

richard

[rbartlett]

I'm not too familiar with the VRV circuit, since it is a heat pump model, do you have a reversing valve installed in the condensing unit?


most heatpumps iseem to incorporate a reversing valve..

however if you see my reply above it may explain why this is not -possibly- the answer

cheers

richard

[Cofreth]

most heatpumps iseem to incorporate a reversing valve..

however if you see my reply above it may explain why this is not -possibly- the answer

cheers

richard

I'm thinking of using the reverse valve control signal to interlock with the radiator flow..

[rbartlett]

I'm thinking of using the reverse valve control signal to interlock with the radiator flow..


I know -which is why I refered you to my previous post...


. And whilst this would indeed lock out the heating completely I fear the customer wants individual room control..


cheers

richard

[phil68]

Why not just tell the customer to use the VRV all year round & have the rads as a back up in case of VRV failure in the winter? Tell the customer that heating a building with heat pumps costs less than with conventional rads.:confused:

[rbartlett]

Why not just tell the customer to use the VRV all year round & have the rads as a back up in case of VRV failure in the winter? Tell the customer that heating a building with heat pumps costs less than with conventional rads.:confused:

because some rooms may want cooling and some may want heating i guess...

cheers

richard

[phil68]

because some rooms may want cooling and some may want heating i guess...

cheers

richard
Isn't that the advantage with VRV? Simultaneous heating & cooling from one outdoor unit:confused:

[rbartlett]

Isn't that the advantage with VRV? Simultaneous heating & cooling from one outdoor unit:confused:

nope -especially the cooling only ones..

cheers

richard

[Karl Hofmann]

So, do we have any details on the type of heating system yet? Number of rooms? Do you intend to use cooling only, heatpump?

[Lazarus]

Sorry if this idea is completely away from youre remit but it is the only one i have as a solution for this...

Install a central 4 tube water system, cool set supplying air coils, hot set to radiators... lose the boiler or set as backup system. Individual independant thermostats in each room can be easily be set to activate heating or cooling as required through solonoids.
Stand alone air/water heat pump controls solely off the temperatures in the central water ring mains and is not affected by individual room requirements.

just a thought !!!!!!

[airefresco]

Just a thought.

Use a Daikin DBACs. I'm sure there's a way you can link the radiators into the system and set rules for exactly what can run when.

I'll have a look for the software and see if it can be done. Im sure we did this a few years ago and it worked a treat.

[rbartlett]

Just a thought.

Use a Daikin DBACs. I'm sure there's a way you can link the radiators into the system and set rules for exactly what can run when.

I'll have a look for the software and see if it can be done. Im sure we did this a few years ago and it worked a treat.


sounds good

cheers

richard