@porthy and what is the ASHP hot water set to?

@derek-m I’ll need to get the installer back.  The system was commissioned on Friday last week, so I admit it’s early days.  We’ve had a Grant Aerona ashp installed, along with a Grant thermal store.  Having just spoken with Grant they suggested it could be the port valves.  We’ll see what the installer has to say about things.  Thanks for your help.

Posted by: @porthy

@derek-m I’ll need to get the installer back.  The system was commissioned on Friday last week, so I admit it’s early days.  We’ve had a Grant Aerona ashp installed, along with a Grant thermal store.  Having just spoken with Grant they suggested it could be the port valves.  We’ll see what the installer has to say about things.  Thanks for your help.

Hi Porthy,

I was actually going to suggest that you get the installer back and ensure that they resolve all the issues to your satisfaction before you let them leave. They should have fully tested your system before they left previously.

It is about time companies were held responsible for poor quality work.

Please update when you get your problems resolved.

@porthy, glad you've recalled the installer, and please let us know if it leads to a positive outcome.

@batalto 38

@porthy your hot water (not your heating) is set to 38°? If that's true, that's your problem right there. Any cold in the tank is going to drop it right down

It’s good news - by the time the installer visited to consider my problem I’d began to experiment with leaving the “call” on the ASHP for longer.  I’m still debating whether it’s best to leave the DHW on demand 24/7 or just those “need” times (pre heated before the need and during them too) when we need both DHW and warmth around our home.  The installer confirmed I’d been treating the system, as one of you guys did, like my old oil boiler.  The results were positive this morning - a warming house and a happy, showered wife!

I now understand that the wireless heating thermostat in the hall triggers the circulating pump that draws heat from the thermal store for warmth to the rads.  Ensuring the domestic hot water stat keeps the thermal store is topped up with heat has led to good warmth around the house and hot DHW too.  One thing I continue to notice is the that the two thermal store stats (one towards the top and one towards the bottom of the thermal store) attached to the tank appear to trigger at around 45 degrees c. and are struggling to get to a higher temp.  However, the installer fiddled with some parameters yesterday and checked inside the ASHP, so I’ll observe this fora while yet.

Thanks to all of you who considered my problem and for your patience.  Now to fine tune to ensure warmth & hot water when needed whilst running a system that is economical.

We are fortunate to have solar panels so on those days the free celestial power will help.  

All the best, Chris.

@batalto I’ve two stats on the thermal store - one towards 5he top and the other towards the bottom.  If set at 55, the heating never seems to come on, but if the tank theromostat at the bottom is manually lowered below 45 the ashp stops heating the water and the in the house pump that circulates the heat to the rads kicks in.  That said, the heat to the rads doesn’t circulate for long, before the ashp is creating hot water again for the thermal store.  I’ve had the installers back and they say to set both thermal store stats to 55.  

Posted by: @mattengineer

Posted by: @porthy

Hi,  like many newbies to the world of ASHP, I’m floundering.  I’ve set the timer to heat the DHW and when this is done the central heating is set on timer to start warming the radiators up.  Problem is by the time someone needs a shower, the hot water has “disappeared”.  Yesterday the DHW, with the help of the Iboost had reached maximum temperature.  The heating then came on and a short time later the DHW was cold.  Where am I going wrong?  Any thoughts will be much appreciated? Thanks.

It might be worth checking that the zone valve connected to your hot water cylinder is closing properly when the heating is turned on. Given the lower flow temperature of the heating it could cool the tank but would likely still be Luke warm I.e. same temp as rads c40c

This is exactly what had happened to my system. I had been running with a 50º flow temp and 50º DHW so the fault wasn't noticeable until I reduced the flow temp to 35º, resulting in a continuous cycle of DHW heating and cooling. Luckily I saw this the next day with the MMPS charts.

https://renewableheatinghub.co.uk/forums/postid/2728

@editor Time for an update!  

Oh dear, still frustrated this end.  Relatively pleased with the warmth in house, but the DHW’s heat continues to disappoint.  I’ve been in touch with Grant in the last few days and they have been very helpful with advice, so I’ve been experimenting.  

Overnight I ensured the central heating did not trigger between 4.30 a.m. and 6 a.m. when I had timed the hot water generation to be on (Grant’s recommendation). THE DHW is also set for hourly boosts late morning and tea time.  

At 10.30 p.m. last evening I had the hall stat drop from 20 to 18 degrees and then at 4.20 a.m. the hall stat was set to reduce to 15 degrees to ensure the central heating pump did not kick in.  The DHW had 1.5 hours to heat up.

At 6 a.m. the hall stat was timed to call for heat at 20 degrees again.  Immediately the rads were really hot, but this changed to a warmth quite speedily.  By 6.30 a.m. the DHW was luke warm, so I needed to put the DHW stat on to heat up the DHW (around 7 a.m. my wife enjoyed a hot shower - hooray) and I switched the central heating stat off.

I understand that you can’t have the DWH and central heating working at the same time, but the DHW seems to be robbed of its heat when the CH is switched on.  It would seem that the CH pump circulates water through the cylinder, but consequently the temperature of the DHW rapidly depletes.

Apologies for being thick, but does the ASHP not build up its store of hot DHW and then when the CH is timed to call for the specific heat you require, pump this heat directly from the ASHP around the CH system, leaving the DWH to sit in the cylinder until required? Clearly, later in the day, should the temperature of the cylinder drop, the cylinder stat would call for heat and as it has priority the CH would be turned off for a while, whilst the heat of the DHW is replenished.

Any thoughts would be appreciated.  THANKS.

@porthy, how incredibly frustrating. We’re having DHW issues (different to yours) too.

Do you have one large cylinder with your HW and buffer in the same cylinder? Could you please take a photo and post it. I’ve been trying to educate myself on cylinders over the past couple of days as we’re also having some unwanted ‘mixing’. 

Sorry to here of your frustrations.

Looking at the handover papers, even in my ignorance, I’m starting to spot factual inaccuracies in the records presented by the installer.  

Here are some pictures of our newly installed tank/cylinder.  Elsewhere in the loft between the cylinder & ASHP, as it were, is a small squat round tank at floor level.

Thanks.