ASHP/ Hot Water Issue

[richo106]

Hi

I have an ASHP that has 100L buffer tank and 300L DHW tank,

I finally had my hot water commissioned couple of weeks ago. I have turned the UFH off left the hot water on and it has kept ticking over the last couple of weeks and has been fine (used hardly any electricity as not been living there)

Yesterday when I was at the house it sounded like water was ‘cycling/flushing’ just within the plant room where all my tanks are which I hadn’t heard before and it was doing constantly and when I checked the energy monitor it has used 100kwh in 24 hours!!

 

I turned the Ashp controller off and it stopped, I had the plumber over today and he turned it back on and it wouldn’t do the same thing but I am concious this will most likely happen again

 

I know this is a very vague issue but has any body got any idea what this could be?

 

literally any ideas/ suggestions will be very much appreciated 

 

many thanks 

[JohnMo]

Is your heat pump control connected to the immersion?

 

What immersion heaters are connected? Buffer and hot water cylinder?

 

Was the noise from the cylinder or buffer? Or general?

 

Was you buffer hot or cold with the heating off?

[ProDave]

100kWh in 24 hours and something is going to get hot.  VERY hot.  Was your hot water normal temperature or scalding hot?  Any sign of discharge through the tundish.

 

That's over 4kW continuous over that 24 hour period, i doubt the HP would / could consume that much  it sounds more like the immersion heater with a failed thermostat and boiling the water in the tank?

 

Keep the supply to ASHP and immersion isolated until you have a proper chance to get it looked at.  Electrician is more likely needed than plumber.

[Marvin]

12 minutes ago, ProDave said:

100kWh in 24 hours and something is going to get hot.  VERY hot.  Was your hot water normal temperature or scalding hot?  Any sign of discharge through the tundish.

 

That's over 4kW continuous over that 24 hour period, i doubt the HP would / could consume that much  it sounds more like the immersion heater with a failed thermostat and boiling the water in the tank?

 

Keep the supply to ASHP and immersion isolated until you have a proper chance to get it looked at.  Electrician is more likely needed than plumber.

100kW!!!  Either the house is very very hot or the heat has left the building! I wonder about the leaking of very hot water.....

[richo106]

37 minutes ago, JohnMo said:

Is your heat pump control connected to the immersion?

 

What immersion heaters are connected? Buffer and hot water cylinder?

 

Was the noise from the cylinder or buffer? Or general?

 

Was you buffer hot or cold with the heating off?

I am going to answer these to the best of my knowledge 🙈😂

 

The immersion heater for the hot water is fed from the ASHP, I think there is just an immersion heater in the dhw

 

it sounded like the noise was from around the buffer tank but the ufh was turned off on the controller 

[richo106]

It’s like it’s tried to do it’s sterilisation but not managed to get upto temperature and just continuously ran

[richo106]

19 minutes ago, Marvin said:

100kW!!!  Either the house is very very hot or the heat has left the building! I wonder about the leaking of very hot water.....

The UFH is off so house not hot and I have checked everywhere and seen no obvious sign off escape of water 

[richo106]

[richo106]

[ProDave]

How hot is your hot water?  Normal temperature or scalding hot?  That energy has to have gone somewhere.

[richo106]

19 minutes ago, ProDave said:

How hot is your hot water?  Normal temperature or scalding hot?  That energy has to have gone somewhere.

Normal temperature

[SteamyTea]

If your 300 litre cylinder was at zero and the immersion heater takes it to 100⁰C, then that is 35 kWh.

About a third what you registered.

And it would be boiling.

Somewhere in your pipework will be a pressure relieve valve, wherever that vents to should show some sign of steam coming out.

[richo106]

[richo106]

2 minutes ago, richo106 said:

Sorry for the terrible video, but this is sound around the buffer tank that is not normal

[ProDave]

15 minutes ago, richo106 said:

Sorry for the terrible video, but this is sound around the buffer tank that is not normal

That really does sound like boiling water to me.

[ReedRichards]

My buffer tank has its own immersion heater, although it was never connected.  I cannot see if there is one in this instance.  

[crispy_wafer]

Cant answer your question, but thanks for the picture, I was looking at doing something similar with trunking, this helps massively with visualisation.  👍

 

16 hours ago, richo106 said:

 

[richo106]

1 hour ago, ReedRichards said:

My buffer tank has its own immersion heater, although it was never connected.  I cannot see if there is one in this instance.

 

My buffer doesn’t have an immersion 

[richo106]

4 minutes ago, crispy_wafer said:

Cant answer your question, but thanks for the picture, I was looking at doing something similar with trunking, this helps massively with visualisation.  👍

 

 

No problem 👍 

I popped a hole in the bottom of the trunking and bought all the actuator cables up centrally and tie wrapped together 

 

[JohnMo]

1 hour ago, richo106 said:

actuator cables

Mine had all those actuators once, all removed as the system never ran correctly.  Big buffer only there because you have lots of zone actuators which act to reduce system volume.  Remove actuators - no need for a buffer.

 

I would check the buffer to see how it's controlled it may have its own thermostatic control. So heat pump operates to keep it hot, UFH pulls hot water from buffer. Switching off the UFH may not switch off buffer heating? Your heat pump then goes into a cycle of run for a minute or so switch off, CoP will be 1 or worse consumption of electricity very high.

[IGP]

I found this interesting