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Hi there,

I have an air source heat pump with a few issues:

1. It gets stuck on defrost mode. When it goes to defrost, it gets stuck and ends up becoming an air conditioner in the depths of winter (fun). I suspect this may be a faulty valve (or what ever reverses the coolant) getting stuck on reverse. I have disabled defrost mode for now by disconnecting the relevant module (bodge fix I know but it's that or I freeze and have no hot water)

2. When the programmer demands heating the pump doesn't kick into action, I have to run the hot water for a bit (to demand hot water) and the pump kicks into action for both heating and hot water, once the hot water reaches temp it shuts off even if heating is still being demanded.

I know there is no issue with the heating system in the house as the rads heat up as normal when the heat pump is on, it's just that it doesn't come on when I demand heating only.

So somewhere there is a link between the programmer and the heat pump broken so the pump doesn't know when heating is being demanded.

What do you guys think I should do? Where should I test?
 

Wilko

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Arms
Esteemed
Hi - can I ask how old is the system and when did it stop working properly? What electrical test kit have you got?
 
  • Thread Starter Thread Starter
  • #4
It's about 5 years old and it has never worked correctly. We moved in to the property this summer so the defrost and heating issue wernt apparent.

I have a multi meter.
 

GBDamo

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Supporter
Hi there,

I have an air source heat pump with a few issues:

1. It gets stuck on defrost mode. When it goes to defrost, it gets stuck and ends up becoming an air conditioner in the depths of winter (fun). I suspect this may be a faulty valve (or what ever reverses the coolant) getting stuck on reverse. I have disabled defrost mode for now by disconnecting the relevant module (bodge fix I know but it's that or I freeze and have no hot water)

2. When the programmer demands heating the pump doesn't kick into action, I have to run the hot water for a bit (to demand hot water) and the pump kicks into action for both heating and hot water, once the hot water reaches temp it shuts off even if heating is still being demanded.

I know there is no issue with the heating system in the house as the rads heat up as normal when the heat pump is on, it's just that it doesn't come on when I demand heating only.

So somewhere there is a link between the programmer and the heat pump broken so the pump doesn't know when heating is being demanded.

What do you guys think I should do? Where should I test?
Can I ask the make? Note not the seller but the company that made it.

Point one is either a parameter issue or a sensor is reading wrong, become detached or has always been in the wrong position.

A heat pump relies on a combination of sensors to function and many sensors have multiple uses.

So one faulty sensor could be the cause of all your problems.

If you can run the HP without the defrost mode without it turning into a block of ice then it shouldn't do it any harm.

Be very observant for ice build up, if it gets thick enough to touch the fans it's goodnight Vienna.

If it is going into defrost without a meaningful amount of ice on the coil then the onset temperature is to high and it will be costing you money.

Very few people get an efficient and reliable heat pump using the out of the box setting. Many areas have their own micro climate and require different settings.


On point two, the module you've removed may have stopped the physical action of the HP defrosting but the program may still think it is defrosting thus not allowing heating.

Do you have a parameter table?

Can you work the controller, the thing on the wall inside?

If so yo can see what each sensor if reading and sanity check it.

EG the ambient sensor could have faulted giving a default -20C reading, if the defrost onset is set at -2C then it will spend a lot of time defrosting.

or the Evaporator Coil exit sensor could be goosed, reading -20C and, depending on the defrost program, it will never come out of defrost.
 

GBDamo

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Supporter
Just noticed the manual you linked.

As it doesn't give any info on default parameters or controller operation its pretty useless.

the only thing I know for sure is it's not a China Palm, a very good thing.
 
  • Thread Starter Thread Starter
  • #7
Thanks for your reply, it is an ideal airtherm 4.5 and by the controller do you mean the programmer where you set the time for the hot water etc or a controller in the heat pump itself?
 
  • Thread Starter Thread Starter
  • #8
I should also mention that the heat pump has never kicked into action when heating is turned on, regardless if the pump is in defrost or not (I have a light which illuminates on defrost) only when hot water is called for.
 

GBDamo

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Supporter
Thanks for your reply, it is an ideal airtherm 4.5 and by the controller do you mean the programmer where you set the time for the hot water etc or a controller in the heat pump itself?
I've had a quick google and can find no info on this maker or model of any use.

All HPs are different but there must be a way to view the various sensors and parameters.

It may be worth giving Ideal a ring, this sounds like the kind of issue that can be solved over the phone IF you have access to to the engineers manual.
 

GBDamo

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Supporter
I should also mention that the heat pump has never kicked into action when heating is turned on, regardless if the pump is in defrost or not (I have a light which illuminates on defrost) only when hot water is called for.
It sounds like it has never been fully commissioned.

A lot of people bought heat pumps and got their local plumber to install them, often they get the mechanics right but totally fail to set the thing up correctly.
 

Wilko

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Arms
Esteemed
Hi - if I understand correctly the HW works and you can use it to get heating running. Are you familiar with S plan systems with two 2 port valves, is that how the ASHP is plumbed (?).
 

Wilko

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Arms
Esteemed
Hi Morgan - for me the next steps would likely be to look at the control system and then the ASHP itself. Sorry to say, but I think you're going to need on site help with this fault.
 
  • Thread Starter Thread Starter
  • #14
Just had a look at 2 port valves. Is it possible that the heating valve is faulty? I.e it opens and closes but doesn't signal to the heat pump that it is open so therefore the pump doesn't operate?
 
  • Thread Starter Thread Starter
  • #15
Hi Morgan - for me the next steps would likely be to look at the control system and then the ASHP itself. Sorry to say, but I think you're going to need on site help with this fault.
I was hoping you wouldn't say that, I had the company out last year and they charged me about 500 quid to replace the defrost module (which didn't fix the problem) they then wanted to replace the smart starter, it seemed that they were just replacing random parts hoping it would fix the problem, charging me for the pleasure. I eventually told them enough was enough and I was not paying them any more.
 
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