Do I just go with the lowest quote for my heat pump?

Jancold · 2024-07-22T11:12:36Z

Octopus are coming around at the end of the month to survey my house. Their quote is half the price quoted by BG. I have had two heat loss surveys and they agree fairly closely with my own from Heatpunk at around 4kW. They would both remove my boiler and put in a slimline tank and a Daikin Heat pump. BG quoted at 45C and Octopus will, I understand, at 50c but I may be able to get Octopus to quote lower. My thinking is that if Octopus are happy to install I would go for that and see how things work out this winter. I would then have the difference in cost to spend on upgrading or adding radiators if needed even if Octopus do not want to replace any. Basically it is the same hardware with the same pipes so why pay thousands more?

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Air Source Heat Pumps (ASHPs)

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Jancold

(@jancold)

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Joined: 3 years ago

Posts: 133

Topic starter 26/09/2025 5:46 pm

@terry1812 sorry my reply was lost as the forum had logged me out.

It definitely is on weather dependant and I have set it to the design and removed the schedules. I shall set the Madoka high and see how the temperature goes.

No they did not give a the full Daikin user manual just some octopus stuff. They did know I was going to 'fiddle' wiith the settings!

Daikin 6Kw ASHP.
MG4 EV
1926 Semi with loft and wall cavity insulation, all radiator.

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Terry1812

(@terry1812)

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Joined: 7 months ago

Posts: 45

26/09/2025 6:11 pm

@jancold Hi again, I Don’t know what you mean when you say you set the madoka high. If you are running on the weather dependent mode (WDM) I don’t think you have to or can set the madoka, (because it should be just acting as a thermometer) but it’s possible. But if you are running on WDM the madoka doesn’t do anything. The ASHP is not referring to the madoka it is only looking at the WDC curve. That’s what will effectively determine what heat you get. And that is why you either have to tweak the WDC or the offset. Having said that I was reading a post on the community.openmonitor site and they were talking about using WDM with the madoka and modulation. Which I’ll admit I’m not clear about. The Daikin engineer who came out a couple of times to look at my system told me that when you use WDM the Ashp doesn’t look at the madoka. If you are using the madoka then once it sends a heat message to the Ashp then the WDC as set up is what the Ashp will refer to until the madoka says it’s hot enough and turns it off. I find the problem with using the thermostat ie the madoka is that it turns on and off and that probably loses efficiency. With WDM it’s on 7/24 and regardless of whether it’s too warm or too cold. It will only ‘rest’ when the return water temperature (RWT) is close to or at the LWT , for my system that never happened, so it just ran on. I do have some issues but that’s for another day and when the weather gets much colder.

But let me know how you set it, maybe there is something else I should be doing.

This post was modified 1 hour ago by Terry1812

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