Posted by: @william1066

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You only need to insulate  pipes inside the thermal envelope of your house if they are causing the room to get to hot.

@william1066 that is the absolute opposite of what was suggested to me soon after my system was installed.

Posted by: @william1066

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think of that central heating pipe as an extra radiator. 

I specifically asked the question re that being a bonus and was informed I should lag and box any exposed pipework and allow all available heat to reach the radiators.

Posted by: @newhouse87

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Dont understand that i could have all loops open on manifold with heat trickling through them constantly.

Only your bedrooms should be set to close the UFH circuit as you will likely want your bedrooms to be at a lower temperature than the rest of the house, though by adjusting the flow rate in the bedrooms you may be able to mimise how often this happens.

Posted by: @newhouse87

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House would get way too hot, weather dependent mode is best practice im told.

Yes, that "weather compensation" will try match the heat loss/load with heat being pumped into the house.  Not easy to achieve, but something to strive for.  You should end up with a long period of heating on, and maybe a long period of heating off, depending on which way the ambient outside temperature is moving, but you should not have many short periods of on/off.

Your hot water [for bathing] should, in most cases, be on a schedule of course.

There is a lot of debate about "always on" vs "scheduled" and which is more cost effective, when using a heat pump.  As soon as I have time to model it theoretically from a "cost" point of view I will share. 

I will post separately on below topic at some point.  My goal is a scheduled heat pump design that maximises CoP, minimises running cost and largely ignores capital and "time" costs while delivering a reasonable user experience.  (sort of custom version of Homely)

My UFH is always open (very few circuits have actuators, but where I have them they are the 'normally open' type) and I "charge" my concrete floor overnight on the cheap rate, slowly. Room goes up by 1.5 degC over night over a period of 7 hours, and the floor goes up by 6 degC, then the opposite during the day.  Charge up takes 7 hours, "cool down" takes up to 12 hours depending on other factors. 

My average [space heating] CoP was about 4.5 last night [outside temperature was 9 degC] that makes it about 16/4.5=3.6p per kWh.  Which is about 38% of the cost of oil.

@derek-m wow,lots of info there. Bit hungover today so i will look in more detail later and get back for clarification if thats ok. yes 2134 is weather dependent for dhw Thanks.

@william1066 Thanks man again lots of info to take in. my issue with heating on during the night, is fan is noisy and im a light sleeper. 1.5deg over 10 hours, maybe my system is ok, i thought it should go up quicker but maybe not so. If i left all loops open in living areas would it cost more to pump through that many loops rather then just a couple when stats call for heat? so would 70kwhs on a cold day be normallish so?

@derek-m 1. Whats the difference between reheat/scheduled vs scheduled?

2. How long should i run disinfection for, like how can i be sure tank was heated to60?

3. Yes they are water pipes, would pressure or flow rates not be fluctuating if air in system?, it only sounds intermittently like that, other times seems ok .

4.With regards to balancing, my bathroom has shortest loop but has more flow rate then loops farther away, e.g kitchen has  3loops but lower flow rate then single bathroom loop. Is that oK or will bathroom take more of the water as thats on when kitchens on?

5. just checked in sensor info, my lwt says 28.2, but on main screen it has desired 34 for weather comp, is it only when pump is switched on to flow for call from heat it will go up?

6. Last one man, sorry so dhw should not have weather dependent feature on, any reason why?

Posted by: @newhouse87

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4.With regards to balancing, my bathroom has shortest loop but has more flow rate then loops farther away, e.g kitchen has  3loops but lower flow rate then single bathroom loop. Is that oK or will bathroom take more of the water as thats on when kitchens on?

Since the actuators are effectively 'digital', the bathroom will take its heat first because the resistance is lower.

But, of course, its thermostat will then turn off, allowing the water to be sent progressively to the longer loops.

In your case there is considerable retained heat in the concrete floor for each room/zone.
So it might take an hour or more before your longest loop is able to draw enough of the flow.

I have a mix of UFH pipes in concrete slab and suspended floor. So I've been able to more easily observe the flow-gauges on the manifold and see what happens over time.

I assume than none of your loops are longer than 100m?

@transparent Issue is my bathroom doesnt have its own stat, its loop is on kitchen stat so will that interfere with my kitchen loops heating up? No none longer then 100m. Flow rate to bathroom is at2.5, should i maybe lower it?

Yes, it will certainly interfere!

Every room requires its own stat/timer.

If your manifold allows the flow-rate to be changed, then by all means do so for the bathroom.
Can we have a photo showing the arrangement of the three components for each loop at the manifold?

• actuator
• flow-gauge
• manual flow adjuster

Thanks.

@transparent

 How do i lower it, down to maybe 1ml? kitchen loops are all approx 2.

Thanks.

So I can see the white mains-powered thermal actuators on the lower (flow) level of the manifolds, and the flow-gauges on the return side.

Which of these also allows you to manually adjust the max flow-rate?

Posted by: @newhouse87

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@derek-m 1. Whats the difference between reheat/scheduled vs scheduled?

2. How long should i run disinfection for, like how can i be sure tank was heated to60?

3. Yes they are water pipes, would pressure or flow rates not be fluctuating if air in system?, it only sounds intermittently like that, other times seems ok .

4.With regards to balancing, my bathroom has shortest loop but has more flow rate then loops farther away, e.g kitchen has  3loops but lower flow rate then single bathroom loop. Is that oK or will bathroom take more of the water as thats on when kitchens on?

5. just checked in sensor info, my lwt says 28.2, but on main screen it has desired 34 for weather comp, is it only when pump is switched on to flow for call from heat it will go up?

1) If my understanding is correct using only schedule will mean that your heat pump only performs DHW heating during the scheduled periods, so you know when it will occur. With schedule + reheat, DHW heating will occur, if necessary, during the scheduled period, but could also occur outside the scheduled period if the temperature of the water within the hot water cylinder falls below the reheat setting.

Your present settings of heat DHW to 48C and reheat at 38C, would maintain the water within the cylinder between those two limits, which means that in practice, at 12pm the heat pump will start DHW heating if the water temperature is below 48C, and will continue heating the DHW until the temperature reaches 48C, or the schedule ends at 1pm. If someone runs a bath at 2pm, and the temperature of the water in the cylinder falls below 38C, the heat pump will start heating DHW again until the water in the cylinder is heated back up to 48C. In schedule only mode, the water would not be heated back up to 48C until the next schedule period.

Because the heat pump can perform DHW heating or CH (Central Heating), but not both at the same time, having scheduled DHW heating means you know when the CH will not be operating. From an efficiency point of view, it is better to perform DHW heating during the warmer period of the day when the heat pump will be operating more efficiently, and also you are less likely to require CH.

DHW production and usage is very down to individual requirements, so you need to assess when you use most hot water and when is the best time to produce it.

2) I read somewhere in one of the manuals that heating the water to 60C for at least 10 minutes will be adequate.

3) Try bleeding out any air that may be in the system. If the noise still persists then provide details of what equipment you have installed within your system.

4) You should balance the flow rates to achieve the desired temperature in each room. The amount of heat energy being transported to each UFH loop is dependent upon the water temperature and the flow rate. If one room is warmer than desired, when all the other rooms are at the correct temperature, then reduce the flow rate to the warm room to bring down its temperature.

Before balancing the system you need to get the WC curve correctly adjusted.

5) For best overall efficiency, during cold weather your heat pump should be running almost constantly, so that it is supplying the heat loss of your home and maintaining the desired indoor temperatures.

As the weather gets milder, your heat pump will commence stopping operation for a period of time and then restarting. This is normal operation provided the on - off does not become too frequent.

From time to time you may see differences between the required LWT and the actual. This could be quite normal as the heat operates to control the indoor temperatures.

@transparent i think there is a red ring around each flow gauge that maybe i need to turn, they seem stiff however.