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Topic Title: Air Souce Heat Pump
Topic Summary: What Controls?
Created On: 06 December 2012 08:40 PM
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 06 December 2012 08:40 PM
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sparkiemike

Posts: 1533
Joined: 24 January 2008

I am working on a project where Mitsubishi EcoDan W140 14KW air source heat pump will be installed.
The installer has given very little info and told the client it is up to the electrician to make sure the wiring is in place and complete the terminations. I intend to contact the installer tomorrow and extract some more information.
All I know is that 3core+E is required for the room stats and that there will be a manifold under the stairs.
The ground floor has 7 underfloor heating circuits in 6 distinct rooms, in addition there is also another heating circuit for radiators on the 1st floor and hot water circuit.
I have worked on systems with multiple zones and multiple boilers but this is a first with a heat pump for me. So before I contact the installer I was hoping someone could provide some basic info just so I am not completely clueless, a link to some wiring diagrams/pipework schematics would be enough.

I assume there will be actuators on the under floor manifold?
Will the 1st floor heating circuit and hot water circuit have separate zone valves?

Is there a separate pump to circulate the water?

What switches the heat-pump on and off, does it have a integrated flow switch or will it require separate controls.

Thanks for any info
 06 December 2012 08:44 PM
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slittle

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I've done three, can't remember the makes at the moment.

The "heating controls" were the same on all three, basically wired as you would with a normal boiler.

The only difference was that the first one of them "free ran" so to speak and just used it's own controls to keep the pipework loop warm. I do remember it was an early to market one so perhaps they hadn't got the control side sorted properly at that stage.

And yes, 1st floor and heating should have zone valves as you would normally.

Stu
 06 December 2012 09:11 PM
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leckie

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Well your not the heating designer are you so ask the heating engineer for the design data in terms of zones, etc.
Each zone, which may be a room or several rooms, will be controlled by The actuators. A thermostat to each designated zone or area will control the actuator/actuators. Usual set up is heatmiser thermostats but could be another make. The heating designer needs to give you this info so that you can wire to HIS design (or hers). Surprised the stats are not 2-wire programable room stats

Edited: 06 December 2012 at 09:18 PM by leckie
 06 December 2012 09:23 PM
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leckie

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Bit more info

The stats will wire back to a control box and the actuators will connect into the control box.

The ashp will need a signal from this control box to call for heat. There will be an independent power supply to the ashp.
 06 December 2012 09:53 PM
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hifly

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I did one last year where the zone stats were wired with cat5 cable, the instructions were very clear what needed doing.

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 06 December 2012 10:08 PM
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leckie

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Well heatmisr do a networked system using cat5e. You need a cat5e to each stat, a link in cat5 between each control unit a nd a 230v out put to the boiler/pump. Also a 230 supply to each control panel.

Be careful with the link cable between the control panel and the ashp. Check if he cable needs to be screened. It will need to be segregated from mains cables. If it is screened it will probably want the screen earthed at only one end to prevent it becoming an aerial
 07 December 2012 07:56 AM
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dickllewellyn

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I've only ever done nu-heat installations, and the use all heat miser stats etc. and hitachi heat pumps. Rhe heat pumps have an indoor control linked as someone mentioned with screened cable, there is then connections for various sensors for weather compensation, flow temp, return temp, buffer temp, and also outputs to contractors for immersion heater backup etc. a wireless programable stat looking affair is used to measure temp in open zones (ie where the ufh loop is permanently open), which rather than just switching on or off will communicate with the heat pump, and between them they adjust the temp going into the floor to gradually raise or lower the room temp at a rate based on all the info gathered from the various sensors. The rest of the ufh zones are individually controlled by room stats which should be thought of simply as opening or closing the loop. They won't actually control the heat pump.

Of course your system may well have no similarities!

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 07 December 2012 08:20 AM
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leckie

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The Ecodan systems have a flow control unit that need wiring in, you need to know the model type and what type of actuator mainifold and stats are being used to work out the wiring.

The use of room stats in floor heating is not as per a standard boiler system. If the whole house is being done it becomes a giant storage heater. The stats really only give a top end cut off, you cant properly send the temperature up and down to order as the "storage heater" takes so long to react. It will take about 2 days to warm the building up from a start point.

As said earlier, the room stats will control the actuators and a signal from the mainfold controller will tell a zone valve to bring in the pump.
When the cylinder stat is calling the flow control unit gives hot water the priority over the heating.
 07 December 2012 09:49 AM
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sparkiemike

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Thanks for the useful replies, will be speaking to the installer later.
 01 February 2013 06:57 PM
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chunk522

Posts: 126
Joined: 12 December 2010

Mike
Ive done three of these and every time the installers have wanted a 32amp supply to the outdoor unit, 32 amp supply to the indoor unit and a 16 amp supply to the cylinder also a fused spur to every manifold for each floor the stats have always been 24volt 2 core cable to every zone/room, the wiring controls have always been connected by the air source heat pump company as the system is commisioned and guarenteed by them.
There didnt look like any complications with the connections they made basically there is a pump at every manifold with the actuators for each zone and the stats wired into the 24 volt control panel at each manifold. There were no zone valves as there was a manifold on each floor
 01 February 2013 09:02 PM
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wylexman

Posts: 68
Joined: 12 March 2011

These are easy i do them all the time, in the mits ftc2 control unit you have 2 heating zones and a hot water zone,
feel free to email me at darrendzzl25@aol.com if you need any info
 01 February 2013 09:53 PM
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SKElectrical

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if you use heatmiser - they are superb - make sure you use wireless stats. they cost about £50 more each but definitely cost effective.
 01 February 2013 11:47 PM
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sparkiemike

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Thanks for the replies, the 1st fix is all done now, the supplier/designer eventually sent through the manual.
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