Water pump operation choices on my Harnitek heat pump
Hi Chaps
I am looking at the water pump operation choices on my Harnitek heat pump .
i have three choices in the software options ,these are..
1) interval working mode
2) on constantly
3) off with compressor .
choice 1 is programmable, so it switchs off with the compressor, but then switches on for a set amount of time , and then off again for a set amunt of time , at the factory setting, its off for 6 mins then on for 1 min etc .repeating .
as far i i can tell with my data logging , this does not work at all , and it simply goes on and of with the compressor .
so i wonder , how do other ASHP's control their water pumps ?
O-er @ivanhoew
You are going to get a mixture of replies to that.
Let me start by suggesting how your heat-pump should've been commissioned....
1: An ASHP should operate continuously, rather than cycle on/off in response to external control (from a thermostat).
That being so, the compressor won't ever be off.
2: Most water circulation pumps have their speed adjusted according to the required flow-rate.
There are pumps which incorporate their own speed modulation...
... but the pump is generally controlled by a (digital) signal supplied from the heat-pump.
So your question implies that your system has been fitted with a circulation pump without modulation 😥
Can I suggest you give us the model numbers for the ASHP and the circulation pump.
If you can photograph the latter, that would be better still.
Building Regulations, Part-L, section-9 requires you to have been provided with site specific information on what has actually been installed in your home.
Do have the system diagram which you could post here?
Save energy... recycle electrons!
its a harnitek 12V1TBA-250L ashp , PUMPis intgral to the harnitek indoor 250 litre tank cabinet , controlled by the harnitek ecu .
pump model is WILO PARA 25-130 /987/1PWM1.
i think this is an ac pwm unit . i can datalog a varying pwm signal , but , when it does this it's also showing as pump status status 0, as opposed to pump 1 which i asumed means its on .
the system runs weather comp ,set v low ,27-31c and cycles between every 20 minutes and greater depending on the FT and ambient .
Re:
"1: An ASHP should operate continuously, rather than cycle on/off in response to external control (from a thermostat).
That being so, the compressor won't ever be off."
I would love to see an example of a heat pump installation that operates continuously ,with the compressor never being off ,with no cycling , in all weathers and times of year ?
from what i have read on here , especially clockworks thread on cycling , it seeems a lot of heat pumps switch on and off ,gaps anywhere from 20 m to an hour . .
what i want to know is what happens to thier circulation pumps when that cycling is happening .
i can log and show graphs if it helps to understand what i mean . 🙂
regards
robert
So you have this model with an integrated 250-litre DHW cylinder.
Posted by: @ivanhoewpump model is WILO PARA 25-130 /987/1PWM1.
i think this is an ac pwm unit . i can datalog a varying pwm signal , but , when it does this it's also showing as pump status status 0, as opposed to pump 1 which i asumed means its on .
The Harnitek data sheet suggests that there are (at least) two pumps
- inside the internal unit, supplying water to the 4-port buffer tank
- after the buffer, in the flow pipe to your radiators, alongside a motorised mixer valve
That requires some detailed expertise/knowledge to commission.
The two circulation pumps could be fighting each other, with the buffer-tank standing between them.
At this stage I don't know which pump you're referring to, let alone how the Harnitek firmware is adjusting the pump speeds in response to the flow/temperature sensors.
Their literature suggests this is a 'black box' which can be quickly installed and that it sorts itself out 🤔
How are you "datalogging a varying pwm signal"?
How does that correspond to what the Harnitek App/Display states?
Posted by: @ivanhoewit seeems a lot of heat pumps switch on and off ,gaps anywhere from 20 m to an hour . .
what i want to know is what happens to thier circulation pumps when that cycling is happening .
I think that question is going to tax the combined efforts of @jamespa @cathoderay and @majordennisbloodnok
because what happens with other ASHPs may not reflect what Harnitek's algorithms do.
What buffer-tank do you have and what sensors are connected to it for flow and temperature readings?
Do you have:
- the commissioning checklist sheet?
- the site-specific system schematic for your particular installation?
- the energy survey report with its system design parameters?
Save energy... recycle electrons!
ThanksTP , no, no buffer tank, one pump .
i log the pwm on my inbuilt harnitek logging SW .
RE:
"Do you have:
- the commissioning checklist sheet?
- the site-specific system schematic for your particular installation?
- the energy survey report with its system design parameters?"
nope none of the above , just the user manual , and the wi fi dongle to connect the pump ecu to my laptop .
dont get me started on eco4 install support !!
i recognise other makes may have different methods , thats what i wanted to know , what those methods are .
with my system i can change all the parameters , but am curious to know what other makes deem the best more efficient way to run the water pump , on all the time , on only with the compressor , or on and off at times intervals independant of whether the ashp is running .
heres an example of compressor and water pump speed changes as logged ...
if yuo look at the legend above you can see what colour means what , and that when the ashp tuns off , so does the water pump , at least its status goes to zero , which i assume meansx its off ...even when its pwm is showing an adjustment ! very odd .
regards
robert
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