How to reduce cycling?

Hardware Heatpump
101

Better/best in what way?

It depends what you want, lowest running costs or highest efficiency.

The two don’t necessarily go together.

The best is the heat you need to have your home as comfortable as you want it at the lowest amount of electricity consumption.

That may mean a lower COP but who cares?

Only you know what is best for you.

I think a lot of us, me included, lose sight of what we are really doing, heating our homes.

One of the big positives of heat pumps is that they can be monitored and the performance assessed.

It is also a big negative!

It tempts us to focus on efficiency and lose sight of the ultimate goal, to heat our home as efficiently as we can in terms of cost.

I think many of us can relate to this and maybe lose our way at times.

2 Likes
102

Hi @matt-drummer

I ask because I can make it run allmost 24 hours with out any stops 6-900 watt at cop around 4 - only some peaks with higher input when running DHW - few stops on 24 hours - like 1 or 2.
Is this better for the pump on the long perspective…
I have been struggling with 150 + start/stop per 24 hour, so this is a new ballgame for me :slight_smile:

103

Hi Arne,

I would think that less cycles than over six per hour has got to be good for your heat pump.

A COP of around 4 is good in my book, of course not the best but if you think about it, 400% efficient is pretty good by any measurement.

If your home is comfortable at this I would consider it as wholly acceptable.

My opinion only, of course but a SCOP of around 4 and not destroying your heat pump sounds quite good?

104

It sounds amazing considering the previous behaviour of 8 cycles per hour and COP at around 2,5
Today have zero cycles per hour - but not sure if that is “good” for the unit in the long run…

I tried to add in 4 stops per 24 hour, long stops of 2 hours, we have the same temperature in the room, but natural airflow stops when no heat is generated from the emitters, so feels a bit cold pretty fast…

105

Hi Arne,

I am the same, you notice when the heat stops.

If the heat pump is happy to keep running, you like the heat and you can afford it, just keep it going.

If nothing else, you’ll be comfortable and the heat pump will be efficient.

You may use a little more electricity this way but if you like it, it’s OK.

Of course, you may not use any more electricity this way, you just use it in a different way.

Do what makes you happy as long as you can afford it.

Compressor starts is what does the damage, continuous running is good.

106

Hi Ian,

Are you able to share more info on how you overrode the fans on a plinth heater?

I need to boost my kitchen heat output but all the hydronic plinth heaters seem to only kick in at a water temperature of 38C or above. I use a few Shelly/sonoff relays around the house but always to turn the whole device on or off. I can’t see that any of the plinth heaters have a fan override option within the main wiring diagram.

Thanks,
Sam

107

the ones I have are from kitchenheaters.co.uk . If you take the lid off, its pretty obvious which one is the 230v switched live to the fan (on the output side of the thermostat) and which is perm live, a multimeter will confirm. then you just tap across that through a relay. mine have the thermostat that is supposedly on at 36 off at 26, but like you I find it needs about 37.5 to activate, so I manually activate it for the lower run temps.

108

My Myson ones have a summer mode that turns on the fan regardless. I have them set to this with a smart plug on each.
I then have an automation that turns on one of them at one flow temp and both at a higher flow temp.
I’ve found that you don’t really want them on at much below 38C flow temp or the air starts to feel cold (although obviously it will still be delivering heat to the room).

One thing that bothers me about them is that when they aren’t on but the heating is water will still be flowing through them mostly short circuiting water from flow to return. I suppose I could have valves but that feels like too much complication and things to go wrong.

109

Or if you don’t have one (as it’s mains), a mains tester neon screwdriver will be good enough.