Posted by: @daniel

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Hello all wondering if it is possible to add monitoring to my heat pump? Was installed a few years ago by Greener Energy and to be honest the performance has been crap. All the radiators were changed along with the hot water cylinder.

Things I notice are struggling to get inside temps above 19c without it running full bore all the time also if heat is not on notice the rads get warm when calling for hot water. Checked the CH zone valance and that’s ok so figure the piping is not correct. 

Also wanting to get rid of the Tado controller and use just the grant controller as from what I have seen on here that is the way to go for best efficiency. Problem is they installed that in the room above the garage which isn’t heated so would need moved presumably. 

Any help or advice is greatly appreciated! I can also try and get some pictures of the piping setup if that helps. 

Welcome to the forum.

I'm not certain on the best way to add monitoring, there may be others on the forum who can help.

Please provide details of your home heating system, heat loss, number of radiators, system performance etc.

I suppose the starting point would be to sketch out the pipework and check if it does appear to be laid out correctly.

You may not need to move the Grant controller, but you will need to ensure that it is operating in Weather Compensation (WC) mode, and that the WC curve has been correctly adjusted.

I would suggest that you read through the manual with regard to WC control and adjustment and then come back to the forum for further advice.

Posted by: @daniel

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Hello all wondering if it is possible to add monitoring to my heat pump? Was installed a few years ago by Greener Energy and to be honest the performance has been crap. All the radiators were changed along with the hot water cylinder.

Things I notice are struggling to get inside temps above 19c without it running full bore all the time also if heat is not on notice the rads get warm when calling for hot water. Checked the CH zone valance and that’s ok so figure the piping is not correct. 

Also wanting to get rid of the Tado controller and use just the grant controller as from what I have seen on here that is the way to go for best efficiency. Problem is they installed that in the room above the garage which isn’t heated so would need moved presumably. 

Any help or advice is greatly appreciated! I can also try and get some pictures of the piping setup if that helps. 

Hi Daniel, I find Openenergymonitor very good although you would need to install a heat meter into your HP circuit. You can see the types of output you can get by following the link in my signature.

Hi all , been looking into getting a heat pump, are there people who will fit second hand heat pumps or is it just new that people will fit, found a second hand grant aerona3 with a water tank for 1500 but not sure if i will be able to find anyone to fit it? Thanks for any help you can give, Aaron

@derek-m Just a thought; if the hot water is still flowing into the radiator circuit when supposedly on DHW, may be worth checking the 3 way valve as it might be stuck partly open. Were this the case, it would restrict the CH flow and prevent full heat reaching the radiators / emitters - just a thought. Regards, Toodles.

Thanks for the replies guys. 

Derek-M, I did manage to get WC on and turn the system temp down to 45c as was set to 55c. Did that last year as it kept freezing up last year trying to hit the old flow temp. 

Bontwoody will have a look at that thanks. Had heard the grant could be optioned with monitoring was hoping it was something I could add on.

Toodles, first thing I checked was the zone valves. They seem to be working fine. Think the issue may be with the return or maybe I should have a second zone valve on the heating circuit. Going to have a good look at the piping next week. 

Posted by: @hektek86

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Hi all , been looking into getting a heat pump, are there people who will fit second hand heat pumps or is it just new that people will fit, found a second hand grant aerona3 with a water tank for 1500 but not sure if i will be able to find anyone to fit it? Thanks for any help you can give, Aaron

Aaron, no reason why not, although you might find it hard to find someone at the moment.  I suggest you try the UK Heat Pumps Facebook group. 

However, if you're in the UK there are grants that will cover the cost of a new ASHP so why would you go second hand?

@daniel

Looking at your sketches, I cannot see any particular problem with the pipework arrangement.

When you say that the radiators are getting warm when the system is in DHW mode, is that all the radiators or just selected ones? Check that the flow through the electrically operated valves is in the correct direction.

If you cannot achieve the desired indoor temperature during cold weather, at what outside temperature does this occur? What are the heat loss calculations for your home?

Hi @daniel, if you can share some info & answer a few questions I'm sure people will try to help & share experience with Grant installs.

17kW Aerona unit vs what calculated maximum heat load?

What age, size (floor m2) and EPC rating property?

To sense check the unit selection. The root cause of your poor heating performance is usually attributable to these factors, singularly or in combination:

a) The heat source is undersized for the heat load (rare, usually ASHP tend to be oversized)

b) The heat source is adequately sized but heat is not reaching your radiator emitters (the most common issue with retrofit installations where a lower flow rate higher delta T flow & return system is being changed out for a higher flow rate lower delta T flow & return system - the system flow isn't high enough to transmit the required heat energy from source to emitters)

c) The emitters are undersized (yours have been replaced, so unlikely, but if they were sized for 55degC design temp when replaced, and you're wanting to run up to 10degC less at 45degC, you could end up with some emitter sizing issues. 55degC is too high for an ASHP install design temperature!)

Does your circuit include a visual flow gauge and flow setter? Grant include in their more recent literature, but it may not have been recommended/required a few years ago.

If it has, what flow rate does it indicate for CH and HW generation? Expect the HW flow to be higher than in CH as it is a much less restrictive piping system.

You have no second circulating pump from your pictures & diagrams, just the one inside the Grant unit? Is it on maximum flow setting? It likely has 3 speeds? Refer Grant installation literature and check the PCB dip switch settings inside the Aerona unit.

How many radiators on your CH circuit and what typical pipework size? Is it usual retrofit of 15mm pipes into rads off 22mm flow and return piping? Or have you any smaller bore pipework, extensive use of plastic rather than copper?

What's your heating control profile? Do you run 24/7, switch off overnight a few hours, have morning and evening heating timed periods?

Can you share a photo of the outdoor monobloc unit in situ? Where it is and what's around it?

@daniel,

do any of the radiators ever actually get hot?  I mean properly hot, not just lukewarm.  Not scalding hot; more like a hot shower or bath.  Answering that could narrow down your issue quite a lot.

@derek-m Yes all the rads get hot. I have just done an hour long test calling for hot water. there has been no heat demand today, currently set at 18c. Last time the pump ran was 0300 - 0350hrs for hot water. After 45mins of running I have recorded the following from the control panel:

00 46c Circulating water return temp

01 56 Compressor operating freq 1Hz

02 85-87c Discharge temp

03 4600 Power consumption 100w

04 600 Fan control number of rotation 10rpm

05 5c Defrost temp

06 12c Outdoor air temp

07 4400 Water pump control number of rotation 100rpm

08 4c Suction temp

09 50c Circulating water flow temp

After writing this down I went around and checked rad temps, first floor 40c+ and ground floor 30c+. Taken with a Fluke62max+. At the start I went round and checked constantly and the first floor heated up first pretty quickly but took about half and hour before the ground floor was warm to the touch.

To be honest it was last winter that I couldn't get it above 19c without it defrosting non stop. That was when I found this site and managed to get the WC on.