Heat Pump Sizing?

QrizB

Can you power the controller (only) via a UPS? It's a bit of a sledgehammer solution, bit should work?

michaels

QrizB said:

Can you power the controller (only) via a UPS? It's a bit of a sledgehammer solution, bit should work?

Not sure - the controller has 3 wires labelled 12v, Ground and Signal which all come from the heat pump.  Now I am wondering what the signal wire communicates and how and whether if there was simply a 12v uninterruptible power supply to the 12v and Ground then it would only need the signal wire to communicate with the heat pump?

QrizB

You'll never know if you don't try

paul991

would feeding the 12 volt supply via a old alarm power supply with battery backup work and be a lot cheaper

FreeBear

michaels said:

QrizB said:

Can you power the controller (only) via a UPS? It's a bit of a sledgehammer solution, bit should work?

Not sure - the controller has 3 wires labelled 12v, Ground and Signal which all come from the heat pump.  Now I am wondering what the signal wire communicates and how and whether if there was simply a 12v uninterruptible power supply to the 12v and Ground then it would only need the signal wire to communicate with the heat pump?

A single wire is either going to be a simple on/off to call for heat or an analogue voltage - Whilst there are methods for sending much more digital information in both directions over a single wire, I wouldn't expect to see it being used on a heat pump.

Looks like 12V DC battery backup supplies are quite common - ebay lists quite a few from £20 aimed at router & IoT devices. CPC & RS do more robust devices intended for alarm/security installations from ~£30.

michaels

FreeBear said:

michaels said:

QrizB said:

Can you power the controller (only) via a UPS? It's a bit of a sledgehammer solution, bit should work?

Not sure - the controller has 3 wires labelled 12v, Ground and Signal which all come from the heat pump.  Now I am wondering what the signal wire communicates and how and whether if there was simply a 12v uninterruptible power supply to the 12v and Ground then it would only need the signal wire to communicate with the heat pump?

A single wire is either going to be a simple on/off to call for heat or an analogue voltage - Whilst there are methods for sending much more digital information in both directions over a single wire, I wouldn't expect to see it being used on a heat pump.

Looks like 12V DC battery backup supplies are quite common - ebay lists quite a few from £20 aimed at router & IoT devices. CPC & RS do more robust devices intended for alarm/security installations from ~£30.

Thing is the display can show the flow and return temps and the operational status of the heat pump which means info must be being passed to the controller and it is not simply an on-off switch

michaels

Shoots and scores, tried a replacement second hand controller, same issue of loosing setting on power off.  Purchased a replacement capacitor and power cycled and settings retained.  Capacitor was 2 quid, paid a guy £35 to desolder / resolder the new one - need to develop that skill myself.

matelodave

TBH soldering doesn't take a lot of skill, have a shufti on Youtube to find out how to do it. You can get a cheap iron for £10-£15 complete with some tools - like this, more than adequate for occasional use - https://www.amazon.co.uk/ULTRICS-Soldering-Adjustable-Temperature-Desoldering/dp/B0BLNSC9H2?crid=NBDO4PRGS2OW&dib=eyJ2IjoiMSJ9.TEivcDAUm7mduwdOi2LCYhEynkIs-NBO2_8Bj4sznBMNhPNPpU9wPIEHPTkonVFmPxzEyA4fIKHUJ7_ooRsyTILTHvlDsSk7GSjThpiazB82mRbGjwweFi95VmqER06Uc1SxJ8Wioy79siN9SBahnsXYxPOVOdTqZg03O6DpxDaUfiOp-J5nE1Z_gob7amruUqB7G7zJE1U51w5sRnbGb4O7dj8WqqU8gocVIAj4MvWhL0BJCyy0yTEqRPiZECj42GA6KQMlNgNwffVP0J_j5kUP3oVheW9bpMO7gs20AaIedt-weZxMFvZ4t3IA4AvYqcYimN4Xdla9WeyzRF1sNnVh9q9ir1xxbo0gmhiiY1ySN-oJDu_i_U2DjvOSjPReFoecPqin9P_DH95JV8t3Z3k12fdEdVlu89G2jJD_OyX4HwXVbZan9OUsj6GyLRiy.yfWTyhYaQBvSSt6BrBbkyHh4RThG3DiNKtPG6dTbBlk&dib_tag=se&keywords=soldering+iron&qid=1737660489&sprefix=soldering+iron,aps,95&sr=8-31&th=1

michaels

So my DIY heat pump is currently whirring away happily but I am still thinking about going with a 'proper' install i the future.

Ideally I would want a 9-10kw unit but this seems problematical, most ranges seem to do up to about 8kw with the smaller, quieter, low min modulation chassis which is ideally what I would want and then jump to say 12kw with the big, noisy, higher min modulation chassis.

There is a 9kw LG but that seems to be in in what I would consider to be the sweet spot.  Any suggestions, looking for reliable 9kw even at -5 and 40c rads / hot water heating flow temps, small 1 fan chassis and sound power of about 55db or less.

NedS

michaels said:

So my DIY heat pump is currently whirring away happily but I am still thinking about going with a 'proper' install i the future.

Ideally I would want a 9-10kw unit but this seems problematical, most ranges seem to do up to about 8kw with the smaller, quieter, low min modulation chassis which is ideally what I would want and then jump to say 12kw with the big, noisy, higher min modulation chassis.

There is a 9kw LG but that seems to be in in what I would consider to be the sweet spot.  Any suggestions, looking for reliable 9kw even at -5 and 40c rads / hot water heating flow temps, small 1 fan chassis and sound power of about 55db or less.

The Samsung Gen6 12kW unit can deliver around 11.4kW under those conditions, so would be running at around 80% of it's rated output to deliver 9kW (compressors are most efficient operating in the 30-70% range, so I wouldn't want to be running for extended periods at near 100%). It's a double-sized 2 fan unit though. If you actually need 9kW of delivered heat, I think the Samsung would otherwise be a good match. Samsung publish tables of integrated Maximum Heating Capacity at different temps, which allow for things such as defrost cycles.