Posted by: @derek-m

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@davew

Hi Dave,

It is quite feasible to connect both pumps to OUT1, since the output is rated a 230v at 1 amp, which equates to 230 Watts of available power. Each pump could possibly draw up to 80 Watts, but normally much less.

It is designated as being for 'Space heating/cooling & DHW' because it is pumping the heated water from the heat pump, so will always be required, when the system is operating.

The DHW circulation pump only needs to operate when the system is in DHW mode, so should therefore be wired to OUT14.

I suggest that you check where the various pumps are actually wired, once you return from work, we can then take it from there as to what is the best course of action.

Hi Derek,

Been back up in the loft  (Big mistake that was)! , and traced cables from pumps to the FTC board

As we suspected the FTC is not wired as the manual with respect to the DHW pump

Then pumps are connected as follows:

OUT1 - TB01 1-2 = UPM GEO - Primary Pump(In Heat Pump Return)

OUT2 - TB01 3-4 = UPM AUTO - Primary Pump(Space Heating)

OUT1 - Connector CNP1 = DHW pump

You can see this on attached photo (ending 059) and clearly see the empty OUT14 - Connector CNP4 connector which should be for the DHW pump.

So does this mean that the terminal block connectors TB01  1-2 are common with the connector CNP1 which confirms what i had thought that the DHW pump runs when the heat pump is running but if the heating circuit pump is running without the heat pump then it should be off.

 If the packaged unit was pre-wired then why has this happened (unless the FTC unit came seperate to the cylinder and was wired by the installer).

Do you think it is safe to change the pump connection over, assume should power down the FTC first, not sure if switching off at the remote controller isolates the whole board or not, will investigate first.

Regarding my other query regarding what pump speed are we adjusting in the FTC settings  -  I have traced what i thought was the speed control cable from the UPM GEO back to connector CN1A (see photo ending 551)..........however in the manual on page 21 Signal Inputs it describes this connector as "Flow sensor input "??  -- The cable from the flow sensor was run into the board with the pump cable and both black so maybe i got the wrong cable.........The cable is a 4 core as seen on photo....is this indicative of either the flow sensor or the pump?.............Sorry but i am a mech /structural engineer with limited understanding of electrical control.

I was thinking that we are adjusting the pump on the heating circuit but it seems to me that this is the Auto pump and we are probably controlling the Primary pump to the heat pump?

@davew

Hi Dave,

Obviously if it was my system I would have probably installed it myself and confirmed that the wiring was correct. You are indeed correct about the connections to CNP1 and CNP4 being wrong, in fact Mitsubishi actually colour coded the connector and socket to help prevent mistakes, CNP1 should have a white connector and CNP4 a red one.

According to the wiring diagram on page B35 of the large manual, the control signal for the main water pump should be connected to CNPWM, which is located in the upper right-hand section of the circuit board.

To maintain your warranty I would suggest the follow.

Obviously the choice is yours to make, but I would suggest initially contacting your installer and explaining that you suspect that your system is not operating correctly, without stating that you have been inside the panel. If you could be there when they are present you could question why there is a red connector on a white base.

If the pump speed control wiring is also incorrect then you may be able to point that out too.

Another option would be to contact Mitsubishi technical help and ask then to clarify how your system is supposed to operate, and ask them to explain why it is not operating as it should.

Posted by: @harriup

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Posted by: @derek-m

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It probably does so because your installer wired both water pumps to the same output. If there is only the one output from the controller then you require an interposing relay, such that when one pump is on the other is off.

The EcoDan preplumbed cylinder would have been, er, preplumbed and prewired in the Mitsubishi factory. Not that mistakes don't happen of course.

DaveW, do you have a screen shot or two of the tank temperatures? How often do you run the heating cycle?

 

@harriup

The wiring is not correct and the DHW pump is running all the time the primary pump is running....see latest post to @derekm

I only run the cycle twice a day on the scheduler so over the last 4 years some energy has been wasted.

@derek-m 

Thanks for your advice Derek.....my system is out of warranty with the installer so I think I will come clean and let them know I have found the issue on the panel.... hopefully they will advise on procedure for correcting it.

That solved hopefully ......but I still can't understand why when I alter the pump speed on the remote controller there is no evidence listening to the pumps of any speed change.....there is a you tube video showing how to change the pump speed and when he changes it on the remote controller you can clearly hear the pump speed increasing......

I suppose first thing is another trip to the loft to check that pump control cable is correctly fitted!!

Posted by: @davew

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@derek-m 

Thanks for your advice Derek.....my system is out of warranty with the installer so I think I will come clean and let them know I have found the issue on the panel.... hopefully they will advise on procedure for correcting it.

 

That solved hopefully ......but I still can't understand why when I alter the pump speed on the remote controller there is no evidence listening to the pumps of any speed change.....there is a you tube video showing how to change the pump speed and when he changes it on the remote controller you can clearly hear the pump speed increasing......

I suppose first thing is another trip to the loft to check that pump control cable is correctly fitted!!

Okay Dave,

If your system is out of warranty then the first problem is easily resolved. At a convenient time, power your system down, wait 10 minutes for everything to discharge, then unplug the connector from CNP1 and connect it to CNP4. There will probably be a latch on the side of the connector for it to be released, and then it should not take much effort to remove the connector.

If you can provide a photo of CNPWM I may be able to advise on what to do next.

Posted by: @derek-m

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Posted by: @davew

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@derek-m 

Thanks for your advice Derek.....my system is out of warranty with the installer so I think I will come clean and let them know I have found the issue on the panel.... hopefully they will advise on procedure for correcting it.

 

That solved hopefully ......but I still can't understand why when I alter the pump speed on the remote controller there is no evidence listening to the pumps of any speed change.....there is a you tube video showing how to change the pump speed and when he changes it on the remote controller you can clearly hear the pump speed increasing......

I suppose first thing is another trip to the loft to check that pump control cable is correctly fitted!!

Okay Dave,

If your system is out of warranty then the first problem is easily resolved. At a convenient time, power your system down, wait 10 minutes for everything to discharge, then unplug the connector from CNP1 and connect it to CNP4. There will probably be a latch on the side of the connector for it to be released, and then it should not take much effort to remove the connector.

If you can provide a photo of CNPWM I may be able to advise on what to do next.

 

Hi Derek,

I have not yet tried swapping the DHW pump connection over although as you have said and from looking through all online manuals it should be connected to CNP4.

I tried talking to Mitsubishi technical yesterday and they could not seem to answer the question why it is pre-wired in the factory to CNP1, they kept going off to talk to colleagues and the conclusion they came to was it was okay but the pump should not be running continuously (Despite it being wired to the same output as the primary pump??)............they said that there could be a problem with the volt free signal inputs on the bottom of the board seeing some stray voltage (sorry but this was a little over my head) and advised checking with a meter.

To be honest i did not feel satisfied with their response.

To further confuse this situation I have noticed running information codes in the manual for Pump time since reset........Upon enquiry through the controller Pump 1 (Primary) shows 21260 hours which over the 4 years sounds credible, the DHW pump only shows 1220 hours which based on the DHW function taking around 1 hour per day also sounds credible.

These figures appear to totally discredit my claim that the DHW Pump is running when the primary pump is???

Do you think that the pump running time could be generated by something else (ie 3 way valve in DHW position).

What I really want to do is to try swapping the pump connection to CNP4 but scared I might do some damage to the board.........based on your experience Derek do you think there is any risk in doing this (Obviously I know enough to be able to swap over the connector and power down etc.

Has anyone else reading this got the Ecodan Pre plumbed cylinder and could check how their system is wired?

Thanks for your help

@davew

You cannot do any damage by swapping over the connector, if you look at the wiring diagram, like CNP1, CNP4 merely connects to a relay contact, which will be open when powered down.

From the point of view of disconnecting the connector, think of a telephone plug, where it is necessary to push the lever on the side to release the latch.

The difference in running hours will merely be the fact that the controller assumes that the DHW pump runs when in DHW heating mode, not when the main water pump is running. There is no sensor on the pump to indicate to the controller that the pump is running.

I afraid that more often than not these days, technical help lines are staffed by people who are often NOT technical or particularly helpful. What's that saying about 'peanuts and monkey's'?

Hi Derek,

What a result!!............Changed the pump connector to CNP4 and pump no longer runs unless required by DHW call for heat.........proved it by forcing a tank reheat on the controller.

According to the manual the DHW pump is rated at 60W ( @ speed 2) and from the running times for the primary pump of 21040 hours, I think this has cost around £400.00 of wasted energy based on current rates.

Taking pump wear and also there must be some heat loss due to the water being pumped around the external plate heat exchanger then this exercise can only be described as a "Win Win" and justifies how valuable these forums are. 

Thanks for your valued assistance and also to anyone else who contributes.

So much for Mitsubishi technical help!!

@mjr my melcloud wireless interface arrived today. during installation, I can confirm that dip switch sw5-2 (advanced auto adaption) is set as active. i would have expected a different readout to '0' against 'dipswitch5' in the developer tools page though, but have no idea of this language 🙃 

@si-fillo The language is json. The output doesn't match your physical setting, though! I'd expect a value of 2 or some other number with the secondleast-significant bit set. Let's hope that it's either that the device hasn't sent the setting to melcloud yet, or that it's something local to your system, or that does rather knock the confidence in the reliability of that output!

@mjr interesting 🤔 

I've just tried again (developer tools) with the same result.

is it possible to decipher what the numbers mean against each switch? for example, dipswitch1 shows 192. can you identify from those numbers which switches within that set are on?

Posted by: @si-fillo

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is it possible to decipher what the numbers mean against each switch? for example, dipswitch1 shows 192. can you identify from those numbers which switches within that set are on?

I was hoping it would be a straight binary encoding, so 192 = 11000000 so if they're numbered 8 to 1 in order as usual, that would mean SW1-8 and SW1-7 are on and the rest of SW1 are off... but that's a problem because there are only 6 switches in SW1 so I don't know. Maybe all of SW1 are off and the non-existent switches are returning 1 for whatever reason.

This part of melcloud isn't documented anywhere that I can see, so we're groping in the dark without a map.