Nibe heatpump. Engineer in the house ??

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Dan_Veluwe
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Post by Dan_Veluwe »

I had a new Nibe heatpump installed in march. Worked OK sofar, but today I discovered something strange.

Its 3-phase system and I assume all three should be loaded equally, but they aren't :?:

current EB100-BE1 0.5A
current EB100-BE2 1.9A
current EB100-BE3 6.7A

The compressor could go up to 120Hz, but is doesn't go above 85Hz.

Room temperature is fine (23.1C, set on 23C), still the 'degree minutes' went up and up..
Then I spotted the electrical addition power was on. Then the compressor was working at 51Hz only : WHY ????

I contacted the firm that installed it. They say the'll look into is, but they have many ill staff and emergencies are served first..

In the information messages [ no alarms ?] I read these :

03/12/2020 12:51:28 High condenser in temperature.
03/12/2020 12:49:24 High condenser out temperature.
02/12/2020 17:57:48 Load monitor active
30/11/2020 23:49:46 Load monitor active
30/11/2020 19:52:01 Load monitor active


Anybody who knows about this stuff can shed a light please :oops: :oops:
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gasgas
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Post by gasgas »

not an expert on heat pumps, but just looking into one for our house so would be interested in knowing more about your system if you would like to share?

rads or underfloor, if rads how much bigger are they
what was heat source before
cost in running as % up or down on old system


thanks
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Dan_Veluwe
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Post by Dan_Veluwe »

No Problem gasgas !

The house has been build in 2007. Ever more stringent insulation requirements from government forced me to use heat recovery from ventilation, or...

The heat recovery from ventilation had pretty bad news . There were problems in houses who had that with fungae an general air quality.

If you start from scratch, you can optimise a system. In existing buildings it is much more difficult since heatpumps with ground loops [most efficient],
are low temperature systems , so you need large systems [mostly floors are used] to install the great lengths of loops you need inside the house.

Today there is more choice since air/water systems now are operable down to - 15C [Panasonic]. The systems when I started could not work below -5C.
So please give me data on your house, since the existing house directs your options greatly.

Before one starts with any heatpump system, you must get the best insulation possible. The biggest mistake made is that people think you can simply replace a central heating system boiler by a heatpump.

If you have a big old country pile, with walls without an air gap, no floor-/window-/roof insulation, you need to adres that before installing a heatpump system.

When I started most designs let the ground source cool down to -5C or more in winter by adding glycol [anti-freeze]. At those temperatures the efficiency is very low. The electricity used is equal [or more!] then the heat you 'generate'. Sometimes its better to heat with supplementary electric heating to cater for the odd cold spell. If very rare a perfectly dimensioned groundsource is over costly, or sometimes [ a small lot] there is not enough space to place the required amount of groundloops.

So first consider : how well insulated is the house, and how much can I gain there. Then : what systems are possible in the context of the existing construction of the house. You could use "hybrid" systems. Most makes allow you to make two systems, eg a low temperature system for floor heating and a higher temperature system for the first and floors above. Personally I would prefer with wooden floor to make heated walls or ceilings [we have that in the kitchen].

Then ; how cold does it get. If you live in the south near the coast I assume it rarely goes below 0C.

Then the best option could be an air/water system. A lot cheaper as groundloops [vertical] are expensive. But if you own a large plot of land, and the watertable is high enough the year around, you can horizontal ground loops in [not in rocky soil, also very expensive].

Then, if you rarely need heating, but you need to cool more often, an air/water system is the best.

We took the previous heatpump out [Nibe 1250 fighter 18kW], which was oversized. In spring and autumn it always operated on its lowest level like a normal on/of system, not efficient I assumed.

Now it proofs it was just as efficient as the smaller system we have now, that does modulate to lower output ranges. The only difference is the old system switched off several hours a day. This one runs 24/7 if outside it goes below 18C 24/7 average.

If you want to see what heatpumps [makes/types] are available and how they perform, you can have a look on this German website. I registered my old and new systems there too.

You can compare once you have a system with other locations that run a comparable setup.

https://www.waermepumpen-verbrauchsdate ... =verbrauch

So feel free to send me info [pm]. We can also keep it public is you give no info on your exact location.
Last edited by Dan_Veluwe on Fri Dec 04, 2020 10:06 am, edited 1 time in total.
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Lunar
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Post by Lunar »

Fascinating stuff - I've a feeling you know more than the people here you are asking the question of Dan!

Any more info. on this would be good to see.

I have a house with fair insulation - walls, loft, double glazing, TRV valves - but with a wall hung cast iron gas boiler installed in 1974!

And yes, with a carbon monoxide detector close to it ;)

The mess it would cause to change it has made it more economical to live with the likely poor efficiency - and then I see the UK Gov. looking to ban gas heating in new homes from 2025.

So I started looking at ground and air heat pumps and those good looking Tesla storage batteries and am now more confused than ever.

You make a very good point about the house itself before the heating system.

I'm thinking I might just wait another few years and let global warming sort things for me :roll:
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Dan_Veluwe
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Post by Dan_Veluwe »

Hi Lunar.

I am hoping a -low profile - engineer pm's me. I'll keep his secret, promise :lol: .

For the carbonmonoxide, you know the stuff is heavier then air and unlike a smoke-/heat sensor it needs to be near the floor, about 40cm above ?
Also it will not sens much if there is a draft on that spot. So if the heater is in a cabinet, put one halfway the floor. If this old heater pulls combustion
air from the house, that draft also pulls carbonmonoxide out. So it could be malfunctioning, compensated by the draft..

Best is to have these checked at least every other year, maybe more often, depending on local regulations and your fire/home insurance policy !!!

As you state they THINK to ban gasheaters from NEW homes...

I would surely replace the gasheater, with a gasheater ! The "1974" model has an efficiency in the low 60-ties..

A new HR model can easily return [no joke] "104%" .. So you could potentially cut you gasbill by 50% !!

But this type of boiler needs a special chimney stack. It has to be doublewalled and insulated as the heat from the exhausts are recovered and you get condensation too. In higher chimneys you might even need an extraction fan to get the fumes out !

Then you can start 'hunting' for problems in your house. If the boiler is from 1974, the house probably is too. That means concrete slabs continuing from your floor into the face of the house. These are huge heatsinks!

If you want to get started, buy a fairly cheap IR-heatgun. It gives a global reading of the surface temperature. These are completely unsuited for reading body temperature as is done now for corona.

What you look for is big differences. So best period of the year is when its coldest. Take an inside wall of your house as a reference, a wall between rooms with comparable temperatures, eg one with a thermometer hanging on it... Then you have an idea of the accuracy of the heat-/thermometer gun.

First point on walls that are on one side livingroom and on the other side unheated, eg with a garage.

You will see that eg the first wall gives 22C and the colder wall only 18C ! An inside wall of a cavity wall can give then 15C if its 0C outside. The wooden frame of a window 16C and the HR+++ window 18C..

So your roof could be 16C too if poorly insulated. Floors in that era of houses are notoriously cold.

If you have a damp problem from water below the house [ I think in the UK you rarely have a crawling space, we have in NL], you could seal the soil with a plastic ground cover that also floats if water gets in there. This avoids evaporation. Then pillows of heatblankets to a fine job.

My parents have a drive-in home from 1968. It is in the wetlands and in winter there was 15cm water under the house in the crawling space. My dad had a groundcover and blankets installed. The humidity dropped from 80% to 60% generally. Floor temperature went from 14C to 19C ! His gas bill dropped 10%.

Feel free to ask, I am happy to share. Retired and not really occupied at all.
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Dan_Veluwe
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Post by Dan_Veluwe »

I am not the type to "sit-back & wait" . Since Nibe did not get back to me, I called them.

With some trouble I got trough to an engineer at Nibe Netherlands.

It all appears to be caused by a "secret" safety margin in their firmware.

Since we run pure water in our groundloops [no glycol], I put the "minimum return" on 4 C to prevent freezing in the system.

What I did not know [and isn't documented], is that there is a 5C safety also in the firmware today, that wasn't there in my previous system.

The effect was that when the return water from the heatpump to the groundloop dropped below 9 C [ my 4C plus Nibe 5C], it reduced power.

On top of that, I misunderstood the heatingline function. I perceived it as the "maximum allowed" heating temperature at a certain ambient temperature, while in fact it was the set temperature !

So since the powercut due to the double margin did not allow a higher output, electric heating cut in !

Also I increased the heatingline since I perceived it as the "allowed maximum" , in order to allow the pump to output warmer water.

In reality the shortage of energy increased. This is counted as "degreeminutes" . Every minute the system samples the actual and set temperatures.

So with a feed of 30C and a set value related to ambient of 34C, every minute the reference got worse [ -4 degreeminutes added.. :roll: ].


What I did today to solve it all :

- set the heatingline to "5 (0) " , typical for the Netherlands;
- set the goundsource circulationpump to 90% ( could go to 100% if really cold);
- reduce the minimum return to "0 C" .

Now it runs with 8.1 C/ 7.1 C (in/out) for the groundloop and 28.6 C / 26.2 C for the central heating.

This is in theory almost the optimal situation.

Problem is in my experience, that high volume and high temperature return for the groundloop gives extra losses due to the soil temperature.
I think its no problem yet as the soil is still above 8 C at a meter dept where the horizontal tubes run to/from the vertical loops.

I agreed with the engineer to let it run like this for a while to see what happens, (its getting colder over the weekend).

But I think I can go back to the "fixed differential" for the groundloop and letting the firmware dictate the pumpspeed. that way I do not waste pumpenergy for nothing. Also I do not loose energy from the loops when relatively warm water returns though the horizontal returnlines. :ugeek:
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Post by DaddyDarren »

Lunar wrote: Fri Dec 04, 2020 10:00 am Fascinating stuff - I've a feeling you know more than the people here you are asking the question of Dan!

Any more info. on this would be good to see.

I have a house with fair insulation - walls, loft, double glazing, TRV valves - but with a wall hung cast iron gas boiler installed in 1974!

And yes, with a carbon monoxide detector close to it ;)

The mess it would cause to change it has made it more economical to live with the likely poor efficiency - and then I see the UK Gov. looking to ban gas heating in new homes from 2025.

So I started looking at ground and air heat pumps and those good looking Tesla storage batteries and am now more confused than ever.

You make a very good point about the house itself before the heating system.

I'm thinking I might just wait another few years and let global warming sort things for me :roll:

Not banning gas heating. Just the gas they burn. Hydrogen will replace Natural Gas in phases over next 5, 10, 15 years. Worcester have been running hydrogen through domestic gas boilers, at their HQ, for a while now. Shortly will be a trial area in Scotland where they’ll cut off an area from the main gas grid & blow hydrogen through.

There will be change, but for vast majority using Natural Gas, a gas valve replacement will suffice.

I’m certainly no expert. Gleaned from a recent boiler course I attended & couple of trade magazine articles.
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Lunar
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Post by Lunar »

Sounds well worth the chasing call then Dan - should be able to fine tune things nicely now.

And interesting to hear Darren - I'll look out for news on that.

In the mean time, my brain being what it is, it brings up 2 immediate questions...

- Will I need to strap my boiler down to stop it floating away?
- And will I be able to recharge my hydrogen car from a drain cock on my boiler?

...you can tell it's been a long week :D
Last edited by Lunar on Fri Dec 04, 2020 6:44 pm, edited 1 time in total.
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gasgas
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Post by gasgas »

thanks Dan, i built my house in 1997, in Devon so not to cold here, when built i fitted much more insulation than need then, bottom line is i have a U-value of 0.4 better than building regs today, so well insulated and cheap to keep warm.

oil boiler now 23 years old and thinking in another 20 years it will be 40 plus, with green grant available up to £5000 from government just deciding if time to change hence my wish to understand the real world of heat pumps.
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Dan_Veluwe
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Post by Dan_Veluwe »

@gasgas

Then the insulation is no issue. Given your location I would go for air/water system. Panasonic is the best quality in that category. But check how the aftersales functions in your area. Do you have floor heating now ? If its no more then 5 inches spaced you could use it as is. If more you could consider to either cover a wall with plasterboard [or ceiling, very efficient for cooling !]. I have not any financial or other link. Just consider it the best about.

https://www.aircon.panasonic.eu/GB_en/ranges/aquarea/
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