GRANT Air Source Heat Pumps

[alibryant69]

hi i have just installed to 15kw grant ashps to a 16th century manor rebuild and a grant 26kw oil boiler to meet the demand for heat and water when the ashp's dont meet the demand, the whole systems set up correctly through a low loss header in the basement... but my problem is the air sources are drawing close to 300 amps when the start up, this spike happens at least 30 times a day and everyone else in the area has problems with their lights etc when this happens, the electric board are now threatening to cut the power to the house... when we went back to grant they didnt have a clued and kept fobbing us off with excuses like they have come out to look at it when they havent and they are making something to fix this??? which if they havent looked at the ashp's how can they know??? has anyone else out there had any similar problems?? many thanks alastair

 

[Gray0689]

Your electricity bill must be a good laugh

 

[alibryant69]

£20 quid a day for them

 

[Gray0689]

£20 quid a day for them

That's over £7000 a year are you mad

 

[unguided1]

are you sure youve got that right 300 amps equates to 69kw on a 15Kw heatpump. If so tell grant to remove it immediatley refund your money and give you some compensation for your electric bills

 

[Gray0689]

You got a big problem shut off the heat pump and just use the oil boiler till sorted

 

[quality]

Started current if DOL can cause the initial current inrush to be 6 - 8 time FLA you could reduce this with a soft start by about 50 %

 

[alibryant69]

thank you just for the record its not on my house but the customers i installed it in but thanks has anyone used these grant aronas before??

 

[Gray0689]

thank you just for the record its not on my house but the customers i installed it in but thanks has anyone used these grant aronas before??

You installed it there is no way that can be set up correctly

 

[quality]

May I why you chose grant

 

[Gray0689]

May I why you chose grant

Grant oil boilers are the best

 

[quality]

I was referring to the heat pump as to which grant are far from the best. but agree with you on the oil

 

[Gray0689]

I was referring to the heat pump as to which grant are far from the best. but agree with you on the oil

I know nothing about heat pumps and at a running cost of £7000 I don't want to either

 

[alibryant69]

it was comisioned by grant themselves and they said it was perfect??? and the customer choose them

 

[Gray0689]

it was comisioned by grant themselves and they said it was perfect??? and the customer choose them

Do you think it is perfect at £7000 a year running cost?????

 

[quality]

I presume it is single phase, if this is the case refer to my previous post on a soft start

 

[Gray0689]

I presume it is single phase, if this is the case refer to my previous post on a soft start

I don't know to many houses on 3 phase
Even with soft start it can't be working correctly with that much draw of electricity

 

[unguided1]

I install 25Kw heatpumps on single phase working on 32 amp mcbs with not a single problem, 300 amps sounds completley wrong to me

 

[quality]

15Kw will be the output of the heat pump hence the input would be around 4 or 5Kw however the 300 or so amp start up is only for a fraction of a second i.e 3 or 4 cycles or 0.02 of a second.
many factors determine start current but it would seem logical to fit a soft start if the electric installation is correct

 

[Electrician]

Hi I know it,s a bit late but only just found this thread I too have installed 2 13kw output Grant air source heaters and we are having no end of trouble with them.....
It seems that when they go into defrost mode the current goes through the roof although in the paperwork that comes with them states that they have a maximum operating current of 30Amps we have seen them taking over 80Amps but only when in defrost mode.... But when you talk to Grant they say it's impossible.... so we have purchased 2 owl electricity monitors to record the electricity useage to attempt to prove that they do take over 80Amps....
I guess it just depends on them beliveing the data collected.... Due to the fact that the engineers have to travel up from somewhere in Sussex ( we are in the West Mids ) they just don't want to wait around for it to happen they just want to be back on the way home asap. But when they do come apparently we are the only people in the country having these problems or so they tell us but I now know this to be lies since seeing this.

How are your problems going are they sorted yet??
might pay us to get together and sort them out???

 

[ecowarm]

Hi,

Is the back up immersion 3kw or (6kw available) kicking in?

That would explain the extra Amps

Edit just noticed the 30Amps includes 3kw immersion but they may have 6kw heaters but that wouldn't take it to 80 Amps?

 

[quality]

how long has the 80 amp current been happening? is it recent or has it been for quite a few months

 

[Electrician]

In Response...

When the current is high i.e going to 80Amps no the immersion heaters are not on the ones we have only have the 3kw heaters.
But in the paperwork it clearly states that the total load is 30Amps should these figures include when the heaters are on?
the label on the rear of the ASHP states that it's running current is only 11Amps but we were told those stickers are not for the U.K market which makes no sense at all as no matter where in the world it is the calculation for the amps on a 240V machine remains the same i.e
watts divided by volts gives you the amps

 

[Electrician]

how long has the 80 amp current been happening? is it recent or has it been for quite a few months

This has been an ongoing problem since around October 2010 they haven't run correctly since they were installed....
they only go into the 80Amps when in De-frost mode. You can hear the compressor getting harder and harder to spin as if there is supposed to be a solonoid to switch over for its de-frost cycle but it doesn't open. so the pressure builds and builds therefore causing the current to creep up and up as the pressure builds. sounds like its just gonna blow up when it reaches its peak the whole ASHP is going to shake itself to bits...

 

[quality]

You need a refrigeration engineer to evaluate the refrigeration/electrical circuits, Where are you based ?