Ecodan issue and wiring 2 separate UFH controllers into one FTC6 controller. Help required.

[connick159]

Hi all,
I'm struggling to get hold of the ASHP mob and sparky who did the initial installs but suspect there is a problem coming from the second UFH8 (heatmiser controller) which is located by the second manifold and controlled by Heat miser room stats.

To help me try to explain... Lets call the new extension "area 1" and the old cottage "area 2".

• Both areas have an UFH manifold each.
• Both areas have a heatmiser UFH8 wiring centre each and,
• both have several room stats connected back to their respective UFH8 wiring centres.
• The UFH8 wiring centres are then both connected back to the Mitsubishi ecodan FTC6 controller.
• Ecodan ASHP is set to Weather Comp to control the flow temps.

Problems:

1. When "area 2's" stats call for heat, the wiring centre in that area lights up for the correct room calling for heat but, when i go back to the FTC6 controller, the heating icon still has the 'Paused' symbol displayed just like when there is no heating being requested at all.
2. At the same time, the flow pipes on area 2's manifold are hot. Sometimes way too hot. Today, the flow temp hit 60 degrees even though weather comp is set to a max of 40.
3. If i force area 1 heating on by turning up a room stat then the heating icon on the ecodan changes from Paused to Play symbol.

 

I'm really at a loss here and can't work out why:
a) the call for heat in Area2 is not making the ecodan heating activate (from paused to play)
b) How the hell can the flow temp go to 60 deg if Weather Comp is set to a max of 40 at -3 deg outside.

 

Any thoughts / tips /pointers would be very much appreciated.

Thanks

Edited February 6 by connick159

[SimonD]

The Heamiser UH8 is a pretty dumb relay wiring centre so I would have a look at the wiring to the heat pump from the UH8 as per the following:

 

Heat Enable
This is the main call for heat for the system, there are 3 connections;
LS = Live Supply
E = Earth
LR = Live Return
Electrically this is a volt free switch, whatever supply is placed on the
LS connection, is fed to the LR connection when there is a call for heat.

 

Then check the wiring at the FTC6 controller.

 

I wonder whether the 60C output is meant for DHW and the wiring centre is calling for that when it should be heating CH?

[connick159]

Thanks Simon,
It seems to work ok when area 1's calling for heat. It's only the 2nd heatmiser unit that it happens on.
Good shout re the hotwater but we have that set at only 43 degrees and its on a timer to come on at 4am to 6:30am. The only time it would go to 60 is doing a legionella cycle which would need the immersion heater to get it up to that. I'll take a look at the 2nd heatmiser wiring centre and maybe post a pic.

[connick159]

Here is a pic of the ufh8 wiring in area 2.
All looks ok. no valve on this 2nd manifold hence the loop 'UFH Valve"

I'll have to check FTC6 as suggested. I've opened it but bamboozled by all the switches etc. Will try and read some diagrams or instruction to find out where the 'heat enable' from this 2nd UFH8 controller should connect to on the Ecodan FTC6.
@simonD - any pointers for where to look in FTC6 first?
Thanks again.

 

Edited February 6 by connick159

[PhilT]

33 minutes ago, connick159 said:

Good shout re the hotwater but we have that set at only 43 degrees and its on a timer to come on at 4am to 6:30am. The only time it would go to 60 is doing a legionella cycle which would need the immersion heater to get it up to that.

In your first post you ask how can FLOW temp go to 60 - in which FTC6 screen are you seeing a flow temp of 60? Is there some confusion with the Legionella hot water temp which is set at 60?

[connick159]

I was looking at the 'Thermister Reading' page. It was the THW1 which was set for the flow temp.

[SimonD]

2 hours ago, connick159 said:

Here is a pic of the ufh8 wiring in area 2.
All looks ok. no valve on this 2nd manifold hence the loop 'UFH Valve"

I'll have to check FTC6 as suggested. I've opened it but bamboozled by all the switches etc. Will try and read some diagrams or instruction to find out where the 'heat enable' from this 2nd UFH8 controller should connect to on the Ecodan FTC6.
@simonD - any pointers for where to look in FTC6 first?
Thanks again.

 

 

Try if you can to trace that cable back to the FTC6. I think these should go into TBI as that's where the inputs go, but these also depend on the DIP swtich settings. Although dealing with an earlier version, here is a thread I found that could be very helpful to read and it's about the same connections.

 

 

I would also look at all your setting as even on weather comp. zones flow temps can be set to 60C I believe.

Edited February 6 by SimonD

[connick159]

Ok, so I looked at the FTC6 now and have found the 2 cables (heat enable) from each of the UH8 controllers. 

What I have found is that they are both wired into the L/N/E block but nothing at all into any of the input terminal blocks.

Given that, I dunno how this is working but it seems to be, just doesn't seem like its working right but... The stats call for heat, the heat pump sends the hot water to the manifolds but how?
And could this also be the reason for the erratic flow temps?

 

Edited February 6 by connick159

[SimonD]

10 hours ago, connick159 said:

Ok, so I looked at the FTC6 now and have found the 2 cables (heat enable) from each of the UH8 controllers. 

What I have found is that they are both wired into the L/N/E block but nothing at all into any of the input terminal blocks.

Given that, I dunno how this is working but it seems to be, just doesn't seem like its working right but... The stats call for heat, the heat pump sends the hot water to the manifolds but how?
And could this also be the reason for the erratic flow temps?

 

 

Have you got a photo?

[connick159]

9 hours ago, SimonD said:

 

Have you got a photo?

 

 

On the other end, the heatmiser UH8, the brown is connected to "Ls" the green and yellow is connected to "E" and black is connected to "Lr".

[ProDave]

13 minutes ago, connick159 said:

 

On the other end, the heatmiser UH8, the brown is connected to "Ls" the green and yellow is connected to "E" and black is connected to "Lr".

WRONG cable.  At the UH8 it is a white 3 core cable connected to the Heat Enable terminals.  You are looking at a black 3 core cable there.  you need to find out where that WHITE 3 core cable ends up.

[connick159]

Nah it's deffo black cable at the uh8 end.

It also had a label on it at FTC (just below my finger) "Heat enable 2."

Hope it's not a totally wrong type of cable he's used as it'll be a bastard to chase a new one between the two points.

 

 

9 hours ago, SimonD said:

 

Have you got a photo?

 

 

On the other end, the heatmiser UH8, the brown is connected to "Ls" the green and yellow is connected to "E" and black is connected to "Lr".

Edited February 7 by connick159

[SimonD]

3 hours ago, connick159 said:

 

On the other end, the heatmiser UH8, the brown is connected to "Ls" the green and yellow is connected to "E" and black is connected to "Lr".

 

So that looks very wrong! It looks like your LR from the UH8 is going to neutral on your FTC control board. I'm surprised there isn't a blown fuse somewhere. Have you checked the voltage you're getting at the Heat enable LS and then LR when it's calling for heat?

 

Have you checked what wires are connected to your TBI.1 & TBI.2 terminal blocks? (bottom horizontal row of the FTC6)

[connick159]

Nothing at all from uh8's connected to the terminal block. Both wires in from each uh8 connected to the same spot on FTC as in pic.

Not checked the voltage back on uh8 when calling for heat.

I have a multimeter somewhere so will do that tomorrow. Thanks again.

I'm baffled as the heating is working and each manifold getting heat when calling for it. Obvs not right though.

[connick159]

2 hours ago, SimonD said:

 

So that looks very wrong! It looks like your LR from the UH8 is going to neutral on your FTC control board. I'm surprised there isn't a blown fuse somewhere. Have you checked the voltage you're getting at the Heat enable LS and then LR when it's calling for heat?

 

Have you checked what wires are connected to your TBI.1 & TBI.2 terminal blocks? (bottom horizontal row of the FTC6)

At the UH8 controller,

With the multimeter, when holding the red probe on Lr and black on Ls there is 0 volts. If I move one probe to the earth I get 5.7v when it's calling for heat.

Same numbers where they connect at the FTC end.

Is it a matter of moving the Ls and Lr on the FTC end into the terminal blocks IN1 and 6 as per the manual?  I assume I can leave the earth as it is.

Edited February 8 by connick159
Added info

[Gary68]

Is the FTC set up for 2 zones, do you have an upstairs that is a separate zone, if the dip switches are set for 2 zones you should see the 1 and 2 under the heat pump symbol.

 

You could wire the 2 manifolds as separate zones, I would have thought you could wire them to the same zone in parallel, its just a signal for the heat pump to start up, it won't care where that signal is coming from.

 

 

 

[connick159]

26 minutes ago, Gary68 said:

Is the FTC set up for 2 zones, do you have an upstairs that is a separate zone, if the dip switches are set for 2 zones you should see the 1 and 2 under the heat pump symbol.

 

You could wire the 2 manifolds as separate zones, I would have thought you could wire them to the same zone in parallel, its just a signal for the heat pump to start up, it won't care where that signal is coming from.

 

 

 

Thanks Gary,

Only a single zone at moment.

The question I have is about the actual wiring task.

The guidance is to wire them into the terminal block on the FTC, which I get. What I'm unsure of is which of the 'strands' within the "heat enabled" cable from the heatmiser controller controller go into the terminal block (there are 3 strands (Lr/Ls/E)) so which ones go to terminal block?

Cheers

Edited February 8 by connick159

[Gary68]

They need to be on IN-1 for single zone operation, that's where my UH8 is wired to, so Lr and Ls need to go to IN-1

 

Edited February 8 by Gary68

[SimonD]

9 hours ago, connick159 said:

Nothing at all from uh8's connected to the terminal block. Both wires in from each uh8 connected to the same spot on FTC as in pic.

Not checked the voltage back on uh8 when calling for heat.

I have a multimeter somewhere so will do that tomorrow. Thanks again.

I'm baffled as the heating is working and each manifold getting heat when calling for it. Obvs not right though.

 

If you check the voltage at the top two wires where the terminals are label L & N on the FTC6, which is TB2, what do you get? You should see mains voltage there. Across S2 & S3 below you should see a variable DC voltage around about 20VDC.

[connick159]

1 hour ago, Gary68 said:

They need to be on IN-1 for single zone operation, that's where my UH8 is wired to, so Lr and Ls need to go to IN-1

 

Thanks Gary, the FTC6 the terminal block looks slightly different but I've now removed them from TB2 and into IN1 and IN6 as per pic.

Turned all power off to do so and when powered back on everything is up and running again. Heating and hot water flowing to both manifolds 

Interestingly, back on the UFH, when measuring the voltage on the heat enabled, it now reads 12v where as before it was 5.

When checking voltage on the IN1 and IN6 on FTC6 they now read 0.012 or something like that.

Where they were connected before, to L/N/E it they were reading 5.7v.

[Gary68]

I'm no expert but if your heat pump is set to a single zone I don't think IN6 will be doing anything as it has be to enabled for 2 zones, if you turn off the thermostats that are linked to the UH8 that is wired to IN1 and leave the thermostats wired to IN6 still calling for heat does the heat pump continue to run?

[SimonD]

SW3.1 is the Dipswitch to enable 2 zones at equal flow temps IIRC. It needs to be set to on.

Edited February 8 by SimonD

[connick159]

1 hour ago, SimonD said:

 

If you check the voltage at the top two wires where the terminals are label L & N on the FTC6, which is TB2, what do you get? You should see mains voltage there. Across S2 & S3 below you should see a variable DC voltage around about 20VDC.

Hi Simon,

Thanks for the continued support in this... Much appreciated!

Where they were connected before, to L/N/E block, they were reading 5.7v.

After moving to IN1 and IN6 on FTC6 they now read 0.012v or something like that.

Now on the L/N/E it reads

 

[connick159]

1 hour ago, Gary68 said:

...if you turn off the thermostats that are linked to the UH8 that is wired to IN1 and leave the thermostats wired to IN6 still calling for heat does the heat pump continue to run?

This happened. The stats on UH8 number 2 are calling for heat and the pump on that manifold is running but... The ASHP itself is showing as Paused when I look at the main controller. The flow pipe is pretty cool to touch too so the heating is not running.

As soon as I call for heat again on the controller connected to IN1 the heatimg fires up (the play symbol is displayed).

[connick159]

1 hour ago, SimonD said:

SW3.1 is the Dipswitch to enable 2 zones at equal flow temps IIRC. It needs to be set to on.

I've now done this and rebooted the system. No change in that 2nd UH8 still not putting the pump into heating mode when stats calling for heat.

Does it automatically set 2 zones once the dip switch turned to on or do I need to do that via the main controller too?

I guess the other option could be to connect both UH8s to IN1 right? Is that doable. Cables are pretty tight as is tbh.

 

This is the option from the instructions that best represent what I'm trying to do.

 

 

Edited February 8 by connick159
extra info for clarity