Air Source Heat Pumps

[Deleted User]

Bonny2000 wrote: »

Just wondering if anyone could assist me. We recently moved into a house which has an eco dan heat pump. Can anyone tell me what setting people have their control panel set to. My house seems too hot or cold. Do people also use seperate room thermostats to control the room temperatures. I was also wondering if people kept their heating on constantly or on a timer? Thanks in advance.

What are the current settings?

Harryo

andrewlato wrote: »

No probs Jeepjunkie,
22mm from HP to manifold, then 15mm PEX to every rad on separate circuit with CP Wilo 3m3 per h ......Manual states 'it is recommended to use 28mm pipe']

Andrew What is the required minimum water flow rate through your heat pump? This is quite critical to ensure correct heat transfer. Most domestic heat pumps really need to operate with a temperature rise of 5 to 7 deg. C at maximum heat output. If that applies to yours then it is most unlikely that 22mm will be adequate. Also if you have TRV's on your rads. then it is essential to either have an automatic by-pass valve or some other facility to ensure the minimum flow rates are obtained at all times. It is also essential to correctly adjust the ABV otherwise heating water will bypass the heating system thus reducing the effective heat output of the system. It is potentially unwise to contravene manufacturers' recommendations.

Bonny2000

The room thermostats are just the basic temperature room thermostats and they do not appear to work to be honest as I may set it to 19 c but our bedroom gets to 22 c (we have a baby monitor). The only thing I can workout is that the living room one does turn off the whole system if I turn it off. The control panel is set at
Water temp heating: 50
Water temp heating eco: (unchangeable figure) then 0
Water temp heating: (unchangeable figure) then 17
Water temp hot water: 55
Think the people before us had it on constantly on a much lower heat but we found that to low so I turned it up but it's too warm for nighttime so I have now placed it on a timer. Was this the right thing to do?

[Deleted User]

Bonny2000 wrote: »

The room thermostats are just the basic temperature room thermostats and they do not appear to work to be honest as I may set it to 19 c but our bedroom gets to 22 c (we have a baby monitor). The only thing I can workout is that the living room one does turn off the whole system if I turn it off. The control panel is set at
Water temp heating: 50
Water temp heating eco: (unchangeable figure) then 0
Water temp heating: (unchangeable figure) then 17
Water temp hot water: 55
Think the people before us had it on constantly on a much lower heat but we found that to low so I turned it up but it's too warm for nighttime so I have now placed it on a timer. Was this the right thing to do?

We have one wireless stat for the rooms with the fancoils and one wall stat to control the room with ufh. Basically the heating is set to ON not timed as such but the temps are varied over a 24hr period e.g. 5:30am to 9:30am 20c, 5:30pm to 9:30pm 20c. Times in between are setback to 17c. DHW is TIMED twice a day at times not to conflict with heating i.e during a 17c period.

Suggest getting hold of a manual from the Mits website for your system which will tell you how to unlock settings. Not that I would recommend that

nande2000

Bonny2000 wrote: »

The room thermostats are just the basic temperature room thermostats and they do not appear to work to be honest as I may set it to 19 c but our bedroom gets to 22 c (we have a baby monitor). The only thing I can workout is that the living room one does turn off the whole system if I turn it off. The control panel is set at
Water temp heating: 50
Water temp heating eco: (unchangeable figure) then 0
Water temp heating: (unchangeable figure) then 17
Water temp hot water: 55
Think the people before us had it on constantly on a much lower heat but we found that to low so I turned it up but it's too warm for nighttime so I have now placed it on a timer. Was this the right thing to do?

Those unchangeable figures are changeable; you get to them by pressing one of the initial settings buttons (I forget which one). So basically your system is set to a max flow temp at 0 degc and a min flow temp at 17 degc.

On our system I have TRVs on all the rads upstairs set to 2.5 so the temp is kept at about 19 degc. Then all the downstairs rads are fully open. What sort of room stats have you got ? The first (wireless) one I had was crap; I noticed a real difference when I changed it for a programmable wired one.

Bonny2000

Thank you both for the advice, its very much appreciated. We have wall thermostats which are wall mounted and none digital (the ones with the wheel in the middle). These are in most rooms but as I said don't appear to regulate the temp. I was thinking about the radiator TRV's but I also love the idea of the system being programmed to a lower temp when we don't need it rather than turning it off which I'm doing now. How would I program that? I have two control panels, one for the heat pump and the other to control the times etc. the one that controls the times does not have a temperature facility. Also do my temperatures sound about right?

[Deleted User]

Bonny2000 wrote: »

Thank you both for the advice, its very much appreciated. We have wall thermostats which are wall mounted and none digital (the ones with the wheel in the middle). These are in most rooms but as I said don't appear to regulate the temp. I was thinking about the radiator TRV's but I also love the idea of the system being programmed to a lower temp when we don't need it rather than turning it off which I'm doing now. How would I program that? I have two control panels, one for the heat pump and the other to control the times etc. the one that controls the times does not have a temperature facility. Also do my temperatures sound about right?

From memory our heat curve is 35c [might be 30c - would have to check] flow temp at 17c to 45c flow temp at -3c. Your sounds quite different which is why your house might be to hot or cold? I used to have the flow temps at 30c - 40c which is fine too but house took longer to warm on freezing cold days so wifey would moan. Can't say I noticed any diff in bills. Still pay npower £88pm for everything which is spot on from my calcs. No bad for an ancient house

The wireless stat we have is Danfoss. Can't remember what the ufh one is although I see it every day...DOH!

Cheers

EDIT: We have DHW set to 50c

Uclan

What size heat pump do I need for a well insulated property with 14 radiators. 4 bedrooms, 2 receptions, a large kitchen diner, hall, inside porch and 2 bathrooms. House is d/g and there is floor and loft insulation(300mm). I'm having quotes but the sizing fluctuates. The house is 175 m2 approx. Built to 2006 building regs at least. Looking at a Mitsubishi Ecodan or a Panasonic Aquera. Mitsubishi is made in U.K. Where is the Panasonic made?

nande2000

Uclan wrote: »

What size heat pump do I need for a well insulated property with 14 radiators. 4 bedrooms, 2 receptions, a large kitchen diner, hall, inside porch and 2 bathrooms. House is d/g and there is floor and loft insulation(300mm). I'm having quotes but the sizing fluctuates. The house is 175 m2 approx. Built to 2006 building regs at least. Looking at a Mitsubishi Ecodan or a Panasonic Aquera. Mitsubishi is made in U.K. Where is the Panasonic made?

Is the house in an exposed location ? have you got any other heat sources ?
Looking at the Mitsu heat loss calc (email them for a copy) it looks to me that you are on the edge of suitability for an 8.5kw/14kw unit. If you have another heat source ( a log burner for instance) then I would definitely go with the 8.5. If this will be your only heat source and or the house is exposed I would go for the 14kw unit.

Have you done a diversity calc to see if your main fuse will take the 14kw (needs a 35A fuse if I remember right) ?

Keep in mind the 14kw unit will cost more to run.

andrewlato

jeepjunkie wrote: »

Hi,

It sounds like you are running a low temp ASHP as if it were a GCH system. I don't know your house but rule of thumb for ASHP rads will be something like 2-3 times the size of rads sized for a gch system. Hence why you get triples now.

By design ASHPs like to run for long periods at the lowest temp you can get away with for max cop.

I could be wrong but it sounds like yours is doing a lot of cycling which will reduce compressor life and cause the issues you are experiencing.

As a comparison our ASHP which is not much bigger runs 13 fan coils, 1 large towel rail and UFH. The fan coils suck so much heat out the pipes the one going in is hot the one going out is barely warm so high flow rates are essential.

All the best!

PS A 14kw Ecodan without tank/controls is £4200ish

HI
thanks for you reply. What is your HP? If it's Ecodan than it's different league to Trianco...
yes I have set it to work like GCH boiler, so it comes on and off when temp in cylinder drops by 5deg(default). That works for me above 2deg ambient. To be clear-It cannot be set to run at 40deg constantly -it will cut out when it reaches 40deg and come off when it drops to 35.(could be 1h or 2h later depends on ambient temp)
What is the best way to set it with this simple programmer?
BTW-What is the correct amount of starts per day for HP?
Trianco manual says:" to oversize rads by 33%" and fair enough mine are oversized by only 20% so maybe there is potential to gain a bit more heat.
But people have to accept that this HP is NOT 12KW at 7deg therefore it CANNOT be said that when my rads are emitting 5.9kw (21deg in house, 7deg ambient)to air there's 6.1kw of not utilized heating power. At this temps HP will produce around 7.6kwh MAX.

Now there's more news to come from Trianco Tech Dept:
On Monday afternoon I rung them as I had an issue with programmer.
With the settings as follows:
ON 12-15 OFF, and ON 20.30-7.30 OFF, the programer would not come off at the second setting and would work all the way until 15.00(from 20.30 previous day)
The Official answer to that was(I quote):
There's an issue with the programmer as it gets 'confused' if you set your programs across two days. The first setting MUST be AM, and the 2nd setting MUST be PM but they cannot overrun into following day'!!!
so i asked if it can be fixed, reset or programmer replaced?:
Answer: "This problem cannot be fixed in any way, that's the way the product is(!!!), the programmer cannot be replaced by another one or room stat"
So then I questioned the heating performance graph and the power input quoted in S1200 manual,(remember i have a submeter fitted) Here's the response:
"This data was achieved in test condition and CANNOT be mirrored on site"
That means this HP CANNOT be rated 12KW (even at 20deg)because it's not possible to get that on site.
I have asked what were the test conditions- but did not get the answer to that.
I understand that heating performance can vary(from test to site condition -different volume of water, different pump etc) but WHY is the power input 20% higher on site then "advertised" in manual. I have seen this HP consuming on average 3kwh or more, that translates to my bills being higher by average of 20%. It's a bit like: my car can do 100mpg but only if i drive it, when you drive it it can only do 80mpg".
Last night we had -6deg, water in the system would only get heated to 31deg before defrost comes on and temp drops to 26deg then gets heated again to about 31deg. It stayed ON all day and we got 17deg in the house- remember it consumes 3kwh!!
With this HP there's an easy way of checking if the water flow is impaired in any way. Sensor 1 (cylinder temp) and sensor 4 (refrigerant temp)- the difference should not be more than 25deg and on my system it never is more than 25deg and it was confirmed by Trianco on the phone on monday as correct water flows are achieved.
Im not sure if MCS checks and of the data supplied by manufacturers or do they just approve products by ticking boxes. It is clear to me now this product is not performing as per manual and had I paid full price for it(2500) I would have been sending it back to Trianco.
Overall I think if the temp where you live is above 2deg on average then HP will perform OK, but at lower temps it will struggle.
My goal was to heat the house cheaper than night heaters i had before. I think it it achievable but only just...