Temperature of boiler?

Tar.Aldarion

Just new to air-to-water heating and have the tank set to 60 degrees, have noticed it rarely gets to that temp, mostly hangs around in the 40s - should it be hitting that temp, what temp should it be usually? I notice on cold days like the past few it works poorly with the temperature now in the 30s, which also makes for luke warm showers instead of hot etc. What temps should the water be?

The house also cooled from 20 to 17 degrees even though the heating is on. Is that usual or an issue? Would have thought it should be able to handle this, especially as it's when it's cold is when we actually need it.

John.G

HP output depends mainly on the outside air temperature (ambient) and to a lesser extent the temperature of the hot water it produces either for HW cylinder heating or C. Heating.

For example if you have a nominally 12kw unit, it will output 11.82kw at a ambient of 7C, 8.72kw at +2C, 8.47kw at 0c & 7.8kw at 0C.

Having said that IF you can heat the HW cylinder only, then it should be capable of doing so at 50C or as long as its setpoint is set to max. The downside of this is that its efficiency falls off, see full screenshot below. DHW only needs to be heated to 60C once/week for legionella protection so having the HP set to 45C should give adequate DHW at 40C and just boost the temperature to 60/65C/week, probably using a immersion heater is the cheapest method.

Some HPs use a electrical (immersion type) heater to keep the output up in very cold weather, this may be settable if installed.

What is the nominal output of your unit?.

Tar.Aldarion

I don't know what mine is, I need to look at these figures and the manual, here is mine: https://cool-energy-shop.myshopify.com/products/cool-energy-ecostore-ce-es300-all-in-one-heat-pump-hot-water-system?shpxid=9b5ab9b5-c4dc-48b3-9c62-2027937acb63

It serves both hot water and central heating, I think there are two tanks and sometimes they mix if there is heat disparity, not sure of the inner workings. Sometimes it will go into legionella mode and try to heat the water to 70, however since it never reaches that temperature ever it will be stuck in that mode forever unless I turn the thing on and off. It has an immersion for cold weather which I leave on.

John.G

Have you got a passive or A rated house?, the max compressor power of this unit is only 1.53kw so at a ambient of 0C it will deliver ~ 3.1kw of heat, if electric element is on then ~ 4kw, assuming its using outside air as its heat source, you would generally install a 8 to 12kw system.

However your house might be using the exhaust air (ventillation) which might mean a output of say 6 to 8kw which may be sufficient to heat some houses.

the_amazing_raisin

Okay, I don't have a huge amount of experience with these types of hot water tank, but I do have an air source heat pump so I'll share my thoughts

First off, drop the tank temperature down to something like 48C, most heat pumps can't get a flow temp of over 50C and if you want the tank hotter then you'll need to use the immersion heaters

There's probably a setting on it somewhere that allows it to use the immersion heaters which is disabled, that might be why it's getting stuck in a loop

A lot of heat pumps will also prioritise hot water over heating, so if it's trying to heat the water then it won't be heating the house

Other than that, how is the unit controlled? There's usually one or two external thermostats linked to the unit

These should be calling for heat on cold days and the unit should then supply heat to the radiators

In general, you want to have the heating controlled via the thermostats and not a timer. You want the thermostats set up as temperature limiters to stop the house getting too hot

Then on the heat pump you need to configure the flow temp so that it's supplying a steady amount of heat to the house to keep it at the desired temperature

You want to avoid cycling the heat pump (it turning on and off) as this is extremely inefficient. This kind of goes against the old thinking of oil and gas where you can just have the heating on for a few hours and then leave it off for the day

Tar.Aldarion

https://www.boards.ie/discussion/comment/120120091#Comment_120120091

Yes it's an A rated place, so the boiler may be insufficient to heat the place at low temps. It currently needs to be replumbed as it can only heat one zone at a time due to installation error, so if it is still like this after I guess I'll contact the boiler people. My neighbour has the same boiler but has a supplementary system outside to aid heating.

https://www.boards.ie/discussion/comment/120120166#Comment_120120166

There is an immersion dial behind a panel that sets when the immersion will turn on, I could mess around with that, I think it's only set to come on fairly low as they had to change it from high, it was never off and cost me hundreds in a couple weeks. There are three thermostats for two zones, currently I have to only have the ground floor UFH heating as the piping is wrong (one pump taking all the heat when both are on), when the ground floor is warm enough it would turn off and upstairs could heat, but in this weather upstairs doesn't ever turn on. Hopefully get that fixed soon by the plumber. The heat pump itself is constantly heating so that's ok, I only knock it off and on so I can see the temps as it won't show me the current temp when it's trying to reach 70.

the_amazing_raisin

https://www.boards.ie/discussion/comment/120120587#Comment_120120587

Okay, I think it's quite possible the hot water is blocking the heating from starting

Maybe try switching the hot water off for a while and see if the rads get hot

Would definitely recommend getting the installer back, sounds like they need to check some of the settings

the_amazing_raisin

There's a heat pump thread over in the renewable energy forum, might be worth posting there to see if anyone there has had a similar problem

https://www.boards.ie/discussion/2055433218/heat-pumps-post-here

youtheman

My brother has one of those heat pumps in an A-rated house. The system is configured such that it gives priority to the hot water tank. You can see from the zone valves that the Central Heating zone valves are closed (even though the thermostat is calling for heat) and the Hot Water valve is open. But the heat pump will only get the water in the cylinder 'luke warm' and you need the immersion to top it up.

If he arrives in the house and wants to get it warm he has to turn the thermostat on the cylinder down. This is the only way to get the central heating working. Eventually it will get to the stage that he can turn the cylinder stat up. But he still needs the immersion if he wants the water hot enough for a shower.

Tar.Aldarion

https://www.boards.ie/discussion/comment/120123723#Comment_120123723

Thanks, the same one as me eh, good to know! Seems like that's not working too well either but that's a good hack to get the heating on though.

John.G

https://www.boards.ie/discussion/comment/120123723#Comment_120123723

Those systems are really designed IMO to use exhaust air from your house if a exhaust system has been installed, if not, and using the outside air as the heat sink then they are really only fit IMO for DHW heating.

"Air is simply ducted in and out of the unit from wherever you wish to take heat from!This could be as simple as two pipes through the wall to outside, working like a standard air to water heat pump taking energy from the outside air. Or it could be placed in a position where there is waste heat around such as a boiler house, factory, kitchen or cellar. Alternatively waste heat could be ducted into it from extractor fans, gyms or ceiling voids ect, and cool air could be returned giving free air conditioning!"

youtheman

https://www.boards.ie/discussion/comment/120123957#Comment_120123957

You can look at the controller to see if it is 'on', or just look at the heat pump outside to see if the fan is running. Then look at the zone valves and you'll see when the heat is being 'directed' to. For my own house (oil) I purchased some little temperature gauges that strap onto the pipe. I have a spare one and I'm going to put in on the pipe on my brother place (in his hot press). Gives you some idea of what temperature in coming into the house from the heat source. https://www.amazon.de/Thermometer-Heating-Thermometers-Temperature-Attachment/dp/B0BJDJ8ZKP/ref=sr_1_2_sspa?crid=Z6QF4G83OQ8Y&keywords=rohrtemperaturf%C3%BChler&qid=1674045113&sprefix=pipe+temperature%2Caps%2C63&sr=8-2-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1