Will a GSHP work on generator?

[Mur Huwcun]

Had a session RTFM earlier and bazinga! Turns out the software control I was aware of, actually stops the HP from firing up... no hardware on/off needed. So thanks everyone for the pointer.

Just need to find out what the wattage is of the immersion coil. Nothing anywhere in the specs or manuals, so an email to NIBE I think.

If it’s a similar NIBE to ours you can set how much kw you want the immersion to use. Do you use the hidden service menu on the screen?

 

[steveR]

If it’s a similar NIBE to ours you can set how much kw you want the immersion to use. Do you use the hidden service menu on the screen?

Yes, I can access all the menus, but nowt about kw settings anywhere in the book or installation manuals.

I'll have a scroll through... It is quite old mind... 2010 vintage, and I know the interface has improved. I have pondered having a remote access so I can do the tweaking on a laptop from the sitting room!

Can you recall what "sector" of the settings it is in on yours?

 

[Mur Huwcun]

Yes, I can access all the menus, but nowt about kw settings anywhere in the book or installation manuals.

I'll have a scroll through... It is quite old mind... 2010 vintage, and I know the interface has improved. I have pondered having a remote access so I can do the tweaking on a laptop from the sitting room!

Can you recall what "sector" of the settings it is in on yours?

There’s an add heat menu somewhere, sure it’s in the hidden menu as it wouldn be accessible to the public!!! I’m sure these installers hate people like us!!!

 

[Bury the Trash]

2. A simple, £2K, 25KVA gennie. However these seem to require that the tractor PTO runs at a genuine 540

a modern tractor fuel system will or should try to keep constant power, running 540 rpm at the shaft in the 1000 pto option if it has it should be fine as long as its a big enough tractor as a starting point of course,
thats what we do anyway, with engine revs at about 1100 or so , its not that loud and i use a welder from it.

 

[steveR]

There’s an add heat menu somewhere, sure it’s in the hidden menu as it wouldn be accessible to the public!!! I’m sure these installers hate people like us!!!

Oh, I have been using that "add heat" menu for a while.... as in everytime the HP goes wrong, usually the starter! I will delve in deeper...

It doesn't seem to be available, even in the engineers menus.. So presumably a fixed wattage.

 

[steveR]

a modern tractor fuel system will or should try to keep constant power, running 540 rpm at the shaft in the 1000 pto option if it has it should be fine as long as its a big enough tractor as a starting point of course,
thats what we do anyway, with engine revs at about 1100 or so , its not that loud and i use a welder from it.

From reading ( a dangerous habit, I agree) the problems arise for a HP, or indeed any other sensitive kit, when another big load kick is. Freezers and the like being a good example.

 

[Bury the Trash]

From reading ( a dangerous habit, I agree) the problems arise for a HP, or indeed any other sensitive kit, when another big load kick is. Freezers and the like being a good example.

ah yes sorry, i know nothing about heat pumps,seems theyre not a simple as they sound.

 

[gmgmgm]

Same here. I no longer need to dig the manual out to get the immersion running... Done it too many times!!

Our immersion system will actually heat the house as well as DHW, although in theory it doesn't... Not sure what rating it is though... Needs a bit more investigation on isolating the heat pump to allow the gennie to run the system...

Well done.

I don't think I can edit my previous post, but for clarity, the Worcester/IVT/Bosch heat pumps can do any heating (DHW or CH) using just the build-in electrical heater (3/6/9kw, selectable, under the advanced "additional heat" settings). It sounds like the Nibe ones will also do this.

When the heat-pump is out of action, I'll usually tell it to just to DHW, as it's much cheaper to heat the house with logs than non-HP electric heating.

 

[Mur Huwcun]

Well done.

I don't think I can edit my previous post, but for clarity, the Worcester/IVT/Bosch heat pumps can do any heating (DHW or CH) using just the build-in electrical heater (3/6/9kw, selectable, under the advanced "additional heat" settings). It sounds like the Nibe ones will also do this.

When the heat-pump is out of action, I'll usually tell it to just to DHW, as it's much cheaper to heat the house with logs than non-HP electric heating.

Installers told us to switch heat pump off completely if any issues and use the tank immersion for DHW as it would be much more economical to run then using the emergency immersion to warm the water to circulate through the pipework and heat the tank. We had a pump issue in the summer of 2020 when Covid etc was disrupting deliveries. I was guestimating going from the Smart Meter that we were nearly a pound a day worse off on electricity using the tank immersion.

 

[gmgmgm]

Installers told us to switch heat pump off completely if any issues and use the tank immersion for DHW as it would be much more economical to run then using the emergency immersion to warm the water to circulate through the pipework and heat the tank. We had a pump issue in the summer of 2020 when Covid etc was disrupting deliveries. I was guestimating going from the Smart Meter that we were nearly a pound a day worse off on electricity using the tank immersion.

I suspect that's more to cover themselves? Turning the heat-pump off but keeping the electric "additional heat" requires access to the installer/advanced settings (on my GSHP) and it would be easy to really break things if a user was not well-informed.

Using the GSHP electric heater shouldn't cost much more than the emergency immersion, as the only difference would be the (fairly small) circulation pump. Perhaps it might cost 2% more than a plain immersion (e.g. a 3kw immersion and 60w circulation pump). If one assumes a GSHP has a CoP of 3, then running an immersion/electric-only should cost about 3x heat-pump cost.

If you have a real immersion heater on the DHW tank, then it would certainly be easier to just use it. Ours doesn't have one, and it would be nice to have another backup form of heating the DHW.

 

[Exfarmer]

I suspect that's more to cover themselves? Turning the heat-pump off but keeping the electric "additional heat" requires access to the installer/advanced settings (on my GSHP) and it would be easy to really break things if a user was not well-informed.

Using the GSHP electric heater shouldn't cost much more than the emergency immersion, as the only difference would be the (fairly small) circulation pump. Perhaps it might cost 2% more than a plain immersion (e.g. a 3kw immersion and 60w circulation pump). If one assumes a GSHP has a CoP of 3, then running an immersion/electric-only should cost about 3x heat-pump cost.

If you have a real immersion heater on the DHW tank, then it would certainly be easier to just use it. Ours doesn't have one, and it would be nice to have another backup form of heating the DHW.

of course there issue own many GSHP and ASHP using the internal immersion in the summer is the distance the pipework travels to heat the tank. in winter this is of little issue as most of the waste heat will be lost to the house but in summer this west heat is not welcome and a pure waste

 

[Mur Huwcun]

I suspect that's more to cover themselves? Turning the heat-pump off but keeping the electric "additional heat" requires access to the installer/advanced settings (on my GSHP) and it would be easy to really break things if a user was not well-informed.

Using the GSHP electric heater shouldn't cost much more than the emergency immersion, as the only difference would be the (fairly small) circulation pump. Perhaps it might cost 2% more than a plain immersion (e.g. a 3kw immersion and 60w circulation pump). If one assumes a GSHP has a CoP of 3, then running an immersion/electric-only should cost about 3x heat-pump cost.

If you have a real immersion heater on the DHW tank, then it would certainly be easier to just use it. Ours doesn't have one, and it would be nice to have another backup form of heating the DHW.

It was their own tech guy that told me, he’s actually very helpfull and will tell me over the phone which settings to change if I’m not sure. They know me pretty well and know that I understand the setup. They actually told me to drop flow temps when weather is mild. I keep it at around 30 degrees or less usually. The curve will actually increase it when outside temps fall below 0. You can actually feel it in the morning if there’s been a frost in the night as the floor slab feels warmer than usuall.

 

[gmgmgm]

of course there issue own many GSHP and ASHP using the internal immersion in the summer is the distance the pipework travels to heat the tank. in winter this is of little issue as most of the waste heat will be lost to the house but in summer this west heat is not welcome and a pure waste

That's a good point Exfarmer. My GSHP is indoors and right next to the hot water tank and the pipes between are insulated, so I think my losses are fairly small. But if you have a DHW tank up in the loft, or far away from the GSHP then you would have more significant losses, warming the house.

 

[e3120]

Are any of you guys running a 3 phase domestic HP? When I considered it, that would have been the way to go (easily available, more suited to size proposed, should lead to longer motor life). Would this negate the generator concerns, assuming sufficient grunt in play?