Mitsubishi Ecodan Heat Pump help needed please

compingkitty

Had a U8 error message on the control panel. Phoned the local heating engineers and they said we should turn the system off outside then open the panel and check the fan was rotating freely. We did this and it was rotating okay. Turned the system back on again outside but now the control panel inside the house is blank. (Not the wireless unit the actual panel on the heat pump itself). Is there a reset button somewhere that I have missed. Spent all day googling and am getting nowhere. Live on a tiny Scottish island, there's no heating engineers here and have been told it will cost 75.00 an hour to get an engineer out from the mainland plus the ferry fees so any assistance would really be very gratefully appreciated.

shinytop

Have you tried holding down the standby button on the main controller?  Can you check power is getting to the FTC (the big white metal box)?  Switch off outside, take the cover off, switch on and see if any lights are flashing.  

compingkitty

Thanks so much for taking the time to reply. Held the standby button and nothing happened.
Went outside and turned it off while partner checked to see if any lights came on inside the FTC when I turned it back on. Again nothing happened. I'm sure it must be a simple fix. I just don't know what!

shinytop

Not sure what else to suggest. It sounds like an electricity supply problem. Has the supply circuit to the ASHP tripped out? It should have its own breaker. Maybe an electrician could check things out; it won't need an ASHP specialist.

matelodave

as @shinytop suggests, totally dead seems to be a supply problem. Without having a bit of electrical experience you'll find it difficult to diagnose unless its pretty obvious, like in the main house fuse/distribution board. 

Grovelling about inside the unit is a bit more difficult and not for the faint hearted unless you know what you are doing, have a wiring diagram and a multimeter to prod around with. There are likely to be internal fuses but you need to know where they are.

matt_drummer

Be careful if you remove the covers to investigate the problem.

There are usually some pretty big capacitors in there that if you touch them in the right(wrong) place will give you a nasty shock.

shinytop

matt_drummer said:

Be careful if you remove the covers to investigate the problem.

There are usually some pretty big capacitors in there that if you touch them in the right(wrong) place will give you a nasty shock.

It's worse than that, the live feed to the ASHP goes through the controller.  I was assuming the OP knows to be careful.

matt_drummer

shinytop said:

matt_drummer said:

Be careful if you remove the covers to investigate the problem.

There are usually some pretty big capacitors in there that if you touch them in the right(wrong) place will give you a nasty shock.

It's worse than that, the live feed to the ASHP goes through the controller.  I was assuming the OP knows to be careful.

It doesn't on mine.

I doubt that any heat pump runs on power supplied by it's controller, it's a lot of power!

The electric supply to my heat pump is through two consumer units, one in my garage that then feeds another on the wall next to the heat pump. There are three supplies to the heat pump, the main heat pump power, the booster (immersion) and the back up heater (a pure electric heater inside the heat pump).

The controller gets it's power from a board inside the heat pump. No power to my heat pump flows through the controller.

There are some large capacitors that are exposed when the cover on the heat pump is removed and they are protected by a clear plastic sheet. Even with the power isolated they store so much energy that if you touch the top of them you will get a nasty shock.

My Octopus installers told me this as one of them had done it. 

shinytop

matt_drummer said:

shinytop said:

matt_drummer said:

Be careful if you remove the covers to investigate the problem.

There are usually some pretty big capacitors in there that if you touch them in the right(wrong) place will give you a nasty shock.

It's worse than that, the live feed to the ASHP goes through the controller.  I was assuming the OP knows to be careful.

It doesn't on mine.

I doubt that any heat pump runs on power supplied by it's controller, it's a lot of power!

The electric supply to my heat pump is through two consumer units, one in my garage that then feeds another on the wall next to the heat pump. There are three supplies to the heat pump, the main heat pump power, the booster (immersion) and the back up heater (a pure electric heater inside the heat pump).

The controller gets it's power from a board inside the heat pump. No power to my heat pump flows through the controller.

There are some large capacitors that are exposed when the cover on the heat pump is removed and they are protected by a clear plastic sheet. Even with the power isolated they store so much energy that if you touch the top of them you will get a nasty shock.

My Octopus installers told me this as one of them had done it. 

I never said the power supply went through the (thermostatic) controller. In Mitsubishi speak, the FTC is the flow temperature controller and is a big metal box with live connections and dipswitches and acts as a power distributor for the ASHP, coming after the consumer unit.  That's the white metal box I said to check and I think the OP understood this.  I also never suggested taking the cover off the outside unit; that was somebody else. 

matt_drummer

shinytop said:

matt_drummer said:

shinytop said:

matt_drummer said:

Be careful if you remove the covers to investigate the problem.

There are usually some pretty big capacitors in there that if you touch them in the right(wrong) place will give you a nasty shock.

It's worse than that, the live feed to the ASHP goes through the controller.  I was assuming the OP knows to be careful.

It doesn't on mine.

I doubt that any heat pump runs on power supplied by it's controller, it's a lot of power!

The electric supply to my heat pump is through two consumer units, one in my garage that then feeds another on the wall next to the heat pump. There are three supplies to the heat pump, the main heat pump power, the booster (immersion) and the back up heater (a pure electric heater inside the heat pump).

The controller gets it's power from a board inside the heat pump. No power to my heat pump flows through the controller.

There are some large capacitors that are exposed when the cover on the heat pump is removed and they are protected by a clear plastic sheet. Even with the power isolated they store so much energy that if you touch the top of them you will get a nasty shock.

My Octopus installers told me this as one of them had done it. 

I never said the power supply went through the (thermostatic) controller. In Mitsubishi speak, the FTC is the flow temperature controller and is a big metal box with live connections and dipswitches and acts as a power distributor for the ASHP, coming after the consumer unit.  That's the white metal box I said to check and I think the OP understood this.  I also never suggested taking the cover off the outside unit; that was somebody else. 

Thanks for clarifying.

I really thought you were saying that the power supply went through the user controller inside the house, when you said controller I naturally assumed you meant the unit generally similar to a central heating programmer, not even a thermostatic controller.

My heat pump is a single piece, everything is inside the heat pump so I was worried that the OP was going inside the heat pump.

It was just a friendly warning about capacitors generally.

No criticism of you or anybody else was intended.

shinytop

I see now I used the term controller to mean different things. Point taken about capacitors and interesting that your ASHP has all the wiring stuff inside the main unit.