UFH controls

[RonDubber]

Can any one help?

I have installed UFH using 'Heatmiser UH8-RF'

I have a Mitsubishi heat pump PUHZ-W85-VAA

The system is for UFH only. The hot water is totally independant.

Does any one know how to connect the controls?

Mitsubishi and Heatmiser can not or do not want to help.

The heatmiser works wonderfully, doing every thing it should for the manifolds. I just need to get some hot water from the heat pump.

I know the heatmiser connections to use are C and NO on the boiler connections (I think).

The Mitsubishi unit as control connections S1, S2, and S3 but they don't know how to connect. It was suggested by Mitsubishi that S1 sould be ignored and use S2 and S3.

This does not work. Do I need another bit of kit?

Please please help if you can. Pics of the panels attached.

[ProDave]

Can you post more of the HP manual, not enough information there.

 

S1,S2 and S3 appear to be power to the indoor unit.  It's the indoor unit you need details of I think?

[RonDubber]

Hi ProDave

This is all the manual tells (attatched pdf) not much use. The picture above is from the inside cover of the unit.

I had 3 quotes before I chose Mitsubishi and all 3 told me I did not need an Inside unit as I was not using it for DHW.

They said all I need to do is control it direct from the FTC (heatmiser)

This is Heatmiser's reply:

"It is the boiler enable connection on the UH8-RF which is the connections on our end.  I am afraid I do not know the connections on the air pump, however whatever you put in on Com will go out on NO, therefore if 230v goes into Com, then it will switch 230v, if on the other hand if 0v goes into Com, then 0v will go out."

Any ideas?

VAA Installation Manual.pdf

[PeterW]

1 hour ago, RonDubber said:

They said all I need to do is control it direct from the FTC

The FTC being referred to is a Mitsubishi FTC - it is their controller. 
https://www.swatengineering.co.uk/shop/mitsubishi-electric-ftc5-ecodan-controller-pac-if062b-e
 

It is the brains of the ASHP and can’t be overriden by using anything else onto those connections as they are proprietary comms lines. 

 

[ProDave]

I am not seeing anything in the documentation yet that shows a "call for heat" input demand to the heat pump.

 

Is this a special or strange version?  Others with Mitsubishi ASHP's have found "room thermostat" inputs that do the job of call for heat.

 

It is the ASHP end that is the issue at the moment, not the Heatmiser.

 

Fig 6.1 refers to A, "Indoor Unit" which implies it has control inputs.  Do you have the "indoor unit" and the manual for it, if not I think you need to get it.

 

And this "indoor unit" is not the controller that peter linked to, that is C in Fig 6.1

[PeterW]

47 minutes ago, ProDave said:

And this "indoor unit" is not the controller that peter linked to, that is C in Fig 6.1

Thats not correct. 
 

Item A on the diagram is the interface unit or the flow temperature controller (FTC) that they are referring to. 
 

It comes as two parts - the first is the control box (A) that has no external visible controls, the second is the remote head unit (C) which is used to programme the FTC - this is what is supplied 

 

 

47 minutes ago, ProDave said:

 

Is this a special or strange version?  Others with Mitsubishi ASHP's have found "room thermostat" inputs that do the job of call for heat.

This is a standard Mitsubishi external unit. Depending on the model they either come with a  5 core control wire to the indoor unit that is not connected to internal power, or this sort that uses a 3 core to control the external unit, but requires it’s own fused spur in the house. 
 

Whomever sold that Ecodan minus its FTC, and then said you could just connect “something” to S1/2/3 was telling lies !! It’s a 24v proprietary control signal that the FTC manages. 

Edited December 18, 2020 by PeterW
Missing image

[ProDave]

3 hours ago, PeterW said:

Thats not correct. 
 

Item A on the diagram is the interface unit or the flow temperature controller (FTC) that they are referring to. 
 

It comes as two parts - the first is the control box (A) that has no external visible controls, the second is the remote head unit (C) which is used to programme the FTC - this is what is supplied 

 

 

This is a standard Mitsubishi external unit. Depending on the model they either come with a  5 core control wire to the indoor unit that is not connected to internal power, or this sort that uses a 3 core to control the external unit, but requires it’s own fused spur in the house. 
 

Whomever sold that Ecodan minus its FTC, and then said you could just connect “something” to S1/2/3 was telling lies !! It’s a 24v proprietary control signal that the FTC manages. 

So presumably inside that "box with no controls" are all the terminals for call for heat, thermostat or whatever they choose to call them?

 

That box with no controls is the "inside unit" they referred to I thought.  but agreed that is what he needs.

[PeterW]

3 hours ago, ProDave said:

So presumably inside that "box with no controls" are all the terminals for call for heat, thermostat or whatever they choose to call them?

 

That box with no controls is the "inside unit" they referred to I thought.  but agreed that is what he needs.

 Correct. It has the terminals for call for heat and the flow sensors etc

[RonDubber]

I think I need to give you a bit of history.

Before I embarked on this I went to 3 companies (i looked at many) before choosing Mitsubishi.

I told them I was putting in UFH on 2 floors. one with 4 zones and one with 7 zones.

I was told they did not supply any thing for UFH but could supply the air / water heat pump.

I chose a company for the UFH equipment (Continal). I then told Mitsubishi what equipment I was using and they recommended PUHZ-W85-VAA as it suited my application and all I would have to do is is connect the heatmiser to the control terminals on their unit. That is why I bought this unit. It wasn't until I installed every thing that I realized that they don't tell you what connects to what.

I have sent an email to Mitsubishi suggesting that their technical department should speak to heatmiser's technical department. I'm waiting for the out come.

If I get a reply you will be the first to know.

[ProDave]

It is NOT a Heatmiser problem.  the Heatmiser unit operates the same way as just about every other UFH controller, so it is not because you have bought an unusual UFH system, so take that out of the argument.  You would have just the same issue if you were trying to run a bunch of radiators with a time clock and a room thermostat.

 

The issue is you TOLD them it was going to feed UFH so anyone specifying the heat pump should know it will need a "call for heat" input which might alternatively be described as a room thermostat input.

 

So on the basis of what you told them, they have specified and supplied an ASHP without the controller that it is normally supplied with.

 

so now you need to go back to your supplier / specifier and tell them what they have supplied is NOT FIT FOR PURPOSE and to take it back for a refund, or make it fit for purpose (by supplying the controller)

[PeterW]

@RonDubber did you go to a Mitsubishi agent or Mitsubishi directly ..? There is no way to directly connect to a heat pump - they all use the same interface unit or Flow Temperature Control irrespective of the external unit and you should have been quoted for one of those also. 
 

The Heatmiser units just use the call for heat or boiler contact to close a contact on the FTC board (marked Room Thermostat from memory) which triggers the FTC to power up the external unit and set the flow temperature for the water etc. 
 

The only way to resolve is to get hold of an FTC unit. They very rarely come up on eBay or second hand as they can be connected to a newer external unit so you may have to bite the bullet and get a new one which are around £750. 

[RonDubber]

Thanks guys. I contacted Mitsubishi direct in the UK. The only thing they questioned when sizing the unit was the min op temp as we are in Normandy,

My electrician said he as trouble all the time getting information out of manufacturers when trying to interfacing 2 bits of kit

Let see if the the 2 companies do talk to each other. I will keep you posted.

It can be resolved. It's just a matter of when.

Thanks again for your time.

[PeterW]

2 hours ago, RonDubber said:

My electrician said he as trouble all the time getting information out of manufacturers when trying to interfacing 2 bits of kit

Let see if the the 2 companies do talk to each other. I will keep you posted.

The interface is really simple - it is a pair of contacts on the FTC. 
 

This thread discusses exactly what you are trying to achieve 

 

 

[RonDubber]

It's been 3 months of discussions with Mitsubishi and they kept telling me different things, so I made an official complaint and put a pore report on the web.

I finally got the help I needed. The last person I spoke to was finally aware of the problem and he admitted that I was given the wrong information from their sales and the technical department had given me wrong and conflicting advise.

PeterW, you are right I must have their FTC and they have supplied me with PAC-IF033B-E.

Finally getting there. I contacted them to say, the heatmiser gives a signal 230V when calling for heat. They replied "The input must be volt free or it will damage the FTC."

Any idea what do I need to do?

Sighting the thermistors and setting the dip switches is ok. It's just this volt free input which concerns me.

[TonyT]

Use The 230 volt to feed a coil of a relay and then use the switched contacts as volt free teminals 

Edited March 17, 2021 by TonyT

[RonDubber]

Thanks Tony. It all makes sense now.

[RonDubber]

Well, the saga continues!

Have installed the FTC exactly as specified. Double checked all the switch settings and double checked again and double checked by my electrician.

Still does not work. What we have noticed is:

On the FTC, led 2 does not light and there is no power to the remote controller supplied with the FTC.

Also on the heat pump (PUHZ-W85VAA) the display shows P2. This code is not shown on any error codes and I can't find any ref to P2 on the internet.

So, we are completely baffled. I am reluctant to contact Mitsubishi tech team as they have completely mislead me from day one. Do you think I should give them another go?

[PeterW]

Who installed the heat pump ..? It sounds like the installer needs to come back and check this as it’s not connected correctly. I would start by powering up the FTC and the heat pump independently disconnected and see what you get. 

[RonDubber]

We installed the heat pump. All it needed was inlet and outlet water connections, single phase power supply and control connections between S2 and S3 on the FTC and heat pump. Every thing checks out ok.

The only requirement on power up is that the heat pump should be powered up before the FTC.

All the installation switch settings are as specified in the manual. The only switch setting to change on the heat pump is SW1-3 switch to on (factory pre-set is off).