Voltage drop in house - what to expect

FranklinMint

That's quite a bit on the 16kva supply

Can you stagger the use of the appliances so they don't overlap with the pump and charger?

Any rural 16kva installation i worked on was always a high quality supply,you wouldn't be expecting major voltage drop coming in .

Dardania

Of all the numbers you’ve shown for voltage, none of them appear to be above 230V?
I must have a read of that EN standard - it’s one thing to allow deviations from the norm, but surely they need to at some stage be around 230V to comply with the EU harmonised voltage?

KCross

FranklinMint wrote: »

That's quite a bit on the 16kva supply

Can you stagger the use of the appliances so they don't overlap with the pump and charger?

Any rural 16kva installation i worked on was always a high quality supply,you wouldn't be expecting major voltage drop coming in .

The two offending items are the car charger and the heat pump. I can move the car charger around but I cant really change the heat pump. It comes on/off as it sees fit so moving the car wouldn't help as they would still clash at some point.


I run some other appliances at night (dishwasher/dryer etc) but they all come on at the very start of night saver rate so they are not the issue and don't ever clash with the car which usually starts between 3-5am and goes off at 8am.

Dardania wrote: »

Of all the numbers you’ve shown for voltage, none of them appear to be above 230V?
I must have a read of that EN standard - it’s one thing to allow deviations from the norm, but surely they need to at some stage be around 230V to comply with the EU harmonised voltage?

Still analysing the data in excel right now, they aggregate the data over 10min intervals and then give the min/avg/max of each of those 10min intervals.... if I look at that avg value and get an average of that over the entire 30+ days it gives me 224V.

The max voltage value is rarely at 230V.... usually 224-228V.. again, within spec as far as they are concerned.

FranklinMint

The average supply voltage 218v at 50amp load is a bit lower than you would like to to see for a 16kva supply.

You say the main mcb is only 63amp

You might only have 16sq tails from the meter to distribution board ,not a factor if distance is short.

KCross

FranklinMint wrote: »

The average supply voltage 218v at 50amp load is a bit lower than you would like to to see for a 16kva supply.

You say the main mcb is only 63amp

You might only have 16sq tails from the meter to distribution board ,not a factor if distance is short.

I checked the tails... they are 25sq.


Just as another reference during low load....

15 Mar 2018 11:06:54
V 221.9 226.1 231.0 (min/avg/max)
A 3.5 3.8 4.5

KCross

For posterity here is the 2 page report they gave me...





Here is the regulation they work towards...


Note the 2nd row in that table. 230V±10% for 95% of the time.
Thats the one they quoted me to show that they are compliant.




For the ~5000 10-min measurement intervals(35 days) I had, 15 intervals were outside the 230V±10%. It would have to happen about 250 times for them to agree that there was a problem that required action on their part!

15 times in 35 days is often enough to cause me an issue if high usage happens to coincide with the heat pump coming on.... which has happened twice in 2 months.

While ESB Network consider the voltage fine it doesnt mean you dont have a low voltage problem!

The heat pump manufacturer has shown me how to up the trip limit on the heat pump a couple of amps as it is set lower than spec by default. So, at least I have that option if it becomes a regular occurrence.



On the the graph, it is a little misleading as it looks like the voltage is between 220-230 all the time. It's not.

They sent me the raw data in Excel format as well.

They have voltage and current readings averaged over 10min intervals and they give min/average/max values for voltage and current for each interval.

The min voltage I got over the 35 days was 205V!
I had 235 intervals that had a min <215V

The spikes in current each day is when the car is charging and the heat pump is on, which would equate to 30A+17A+background-load=50-60A.

vintagevrs

Mods,

Sorry to revive an old thread but seems to be very similar situation to me in regards to problem with a heat pump. I can start a new thread if needed?

We have an upgraded supply as heat pump was in spec when building house and ordering ESB connection, so we have a 16kva connection.

Our heat pump over the last few years has destroyed a number of soft start units. This time last year, ESB put a meter on the line, and admitted the line was out of spec. They then said they would do some upgrade work, then reneged on this as a level 2 manager got involved. They replaced the cable from the pole to my box, and I was suspicious they were only doing this as it was the most visible work we would see, as it was at our home but would do no harm. I asked why they were replacing it, had they suspected it to be faulty and they hadn't. I had a complaint open with the regulator about ESB lack of action, and that is now closed with a tiny payment to me from ESB recommended by the regulator for their delay in action.

So the heat pump can then work for months without issue and then start giving issue again. Before Christmas it started playing up again. The issue is that the compressor does not start, but the heatpump (Nibe) does not realise this so no errors/alarms and only sign is that the hot water is no longer hot. To fix this, power cycling the pump sorts it. Issue may not return then for a couple of days.

Problem has been getting worse lately though, maybe every 2nd or 3rd day. I recently got a Omega voltage logger and have this installed beside the heat pump to see if it is the supply to the pump, might be internal wiring issue.

This morning the pump failed to start and I have the voltage monitor on at the time, capturing readings every 5 seconds.

This stuff isn't my area at all so I am not sure if the variation here is totally normal. I know ESB won't really look at any issue below 207V?




Does the fact the heat pump had issue during this time, point to an issue more so with the pump rather than the supply?

Sorry for long post


Cheers

Hintel

Those voltage variations look normal at first glance

Hintel

Fluctuations^^

Tails142

I'd agree that those volt levels are in the normal range from what I can see

KCross

vintagevrs wrote: »

So the heat pump can then work for months without issue and then start giving issue again. Before Christmas it started playing up again. The issue is that the compressor does not start, but the heatpump (Nibe) does not realise this so no errors/alarms and only sign is that the hot water is no longer hot. To fix this, power cycling the pump sorts it. Issue may not return then for a couple of days.

It should detect if the compressor doesnt start. There are sensors all over the place in these heat pumps. If the compressor doesnt start it will know based on numerous sensor values/temperatures.

So, thats strange that you see no errors/faults appearing.

I think you need a HP service engineer to come out and put it through its paces.

What model Nibe do you have?

The Nibe soft starters are also known to be weak. Mine was replaced once by a different make of soft starter that the engineer was happy to stand over based on his experience.


And as others said, the voltage ranges in your graph are quite good although the graph is in 10min intervals so its hard to tell for sure.

What was the lowest voltage value that was recorded by the logger during that time? Was it the 225V that the graph suggests?

2011

Yes, the variations shown on the graph would not concern me. If I had sold this kit to you my first port of would be with the manufacturer of the heat pump. You have been supplied with a piece of kit that keeps failing so the issue is due to either:

1) How it was installed
2) The ESB supply
3) Due to an issue with the heat pump itself

Your contract is with the contractor that installed this kit. He / she needs to resolve this for you. I would be wondering if the soft starter is suitably rated and questioning the quality of the unit. Generally I use quality soft starters such as ABB and I have never seen them fail. Having said that I only use 3 phase units.

I certainly wouldn't go fiddling with it myself. Park the problem back with the installer.

vintagevrs

The installer has been here frequently and trying to resolve. It's a tricky one as it's so intermittent just. It's a f1245 unit if that makes a difference installed in 2012.

I'll be going back to them now as I feel the failure to start this morning when there was no voltage issue really rules ESB out. I also find it bizarre that the unit does not realise there is an issue as there is no delta in the brine in/out temps and the degree minutes continue to fall as no heat heat being generated but apparently it can't. Newer units maybe do not have this issue.

Thanks all for your input.

2011

vintagevrs wrote: »

The installer has been here frequently and trying to resolve.

That is unfortunate.
However, from your posts I would take the view that the installer sold you something that has never worked satisfactorily.
As such I would take the position that the installer must repair, replace or refund you. So far despite his efforts this has not worked.

So perhaps you need to bring this to a head?
I would suggest that you insist that the installer brings a representative from the manufacturer to inspect the installation and make a formal report.

It's a tricky one as it's so intermittent just.

Although this may make the issue more difficult to resolve it does not absolve the installer from his responsibilities.