Looking for some input and or help on my heat pump install and general performance over the first year.
Having according to MelCloud and the handy MEL Pump App achieved a combined COP of 2.1. Cant help but think this could/should be going better.
I have UFH downstairs currently set up in two zones at a central manifold, and then 3 radiators upstairs with a wireless thermostat 2 bed mid terraced house. Internal walls insulated, double glazing and loft insulation
Currently running with a weather compensation curve that was straight up copied from youtube, have been given essentially zero guidance from installer and any opinions would be greatly appreciated.
Hopefully these images help paint a picture
We have a lot of collective experience here on the forum, and would be happy to help you out.
First, it would help to know how your system is running, so I’ll ask a few questions:
is your house generally warm enough in cold weather?
what’s the estimated heat loss for your property?
how much electricity and heat does MelCloud report for the past year?
how hot is the hot water tank heated up to, and how often?
I’m guessing that the primary flow and return pipes are in the bottom-left of the loft picture, beneath the yellow insulation? It would be worth finding and checking the two temperature probes that will be on those pipes, and check that have been fitted securely.
Downstairs stays at the set temperature of 18 ± 1 degree very consistently, upstairs however it doesnt ever meet the set temperature of 18, but the radiators only come on occasionally and only luke warm. Is this maybe a fault of my weather compensation setting?
The estimated heat loss is down as 10548 kWh, but this is based on slightly higher set temperatures and includes a small unheated porch in its total.
Total used - 1531kWh
Total Heat - 3218 kWh
Water - 320 kWh 673 kWh
Heating - 1211 kWh 2546 kWh
Tank is heated to 50 once a day and this is usually sufficient, normally just do this manually late afternnoon for the evening.
I have found the temperature sensors on the far left(under the pump) and the 4th from the left (under the filter). Not sure what I was expecting,
RHS under filter
Not had its first service yet, was hoping to get it performing better, otherwise service may change into getting someone in to have a look at performance as well.
Who installed that, Fred Scuttle plumbing? (see Benny Hill)
The flow sensor looks like a Sika. The Sika data sheet has this to say …
Vortex flow sensors are not completely independent of the flow profile due to their principle. A calming section is therefore necessary. In order to achieve the highest possible measuring accuracy, straight inlet and outlet pipes with an appropriate inner diameter should be used (VVX15 = 13 mm • VVX20 = 9 mm • VVX25 = 25 mm • VVX32 = 32 mm • VVX40 = 40 mm).
The temperature sensors look like they are strapped to the pipe with insulating tape! They should be firmly attached to the pipe (purpose designed clip, maybe Jubilee Clip in extremis) with heat transfer paste between the sensor and the pipe. Then the whole section of pipe should be covered with insulation, the more the better. You might then get a reasonable approximation to the temperature of the water flowing in the pipe.
Thanks for the feedback on the plumbing, at least its not my work though I did pay for it.
I have inquired for some Hebotec TFC6 22, which seem to be about the best for the job without replacing the probe with its own clamp? For paste will thermal compound used in PC building be sufficient here?
As for the flow sensor does seem like poor placement, will look to getting that moved at the first convenient time. Though not sure where on the run its on it could be improved, with the two Ts further up.
Looks ideal. Spring clip so will expand/contract with pipe
Yep, fine.
To be fair, they at least put a swept bend after it, and I assume the valve just out of shot is a full flow ball valve, if not might be worth changing.
Problem with badly installed sensors is that you are only looking at measuring small differences in temperature, sometimes dTs as low as 2 degrees, so even small errors will lead to misleading COP results.
i have had to alter the setting on loads of these where the installer has just left everything on factory default.
On the mel app you should be able to download (reports,energy usage,select date range, download rhi mmsp report) this will give you a breakdown of cop between heating and hot water.
your overall cop should be in the region of at least 3. most i have come across had results like yours of 1.9 to 2.3 and changing the following settings put them up to over 3 straight away.
change hot water temp to 47
dhw max temp drop change from 10 to 18
change heating curve . 45 down to 42 for minus 30 to minus 5… then other end of curve set at 25 @20 degrees
on the mel app look at the differential for the flow and return when it is heating the hot water this needs to be around 5 to 7.
And then look at the hourly heating report for each hour and see how many times it restarts each hour. if this is more that twice an hour it will severley affect your efficiency. Every time a heat pump starts it can use as much as energy as running for 30 mins. it takes a few minutes for the compressor to get up to full effeciency
Thank you for the additional settings to look at, I can imagine a lot of mine will be default where they could be!
My COP numbers have improved greatly, just on the improved contact of my flow and return thermostats thanks to the great help from people here.
A view of my last 7 days just to show the quick change in performance numbers.
