My Nightmare Heating System

[SteamyTea]

8 minutes ago, newhome said:

Hmm, my take on that would be that all of the toxic additives are being KEPT inside! Better out than in and all that! 

You really don't understand boys do you

[newhome]

1 minute ago, SteamyTea said:

You really don't understand boys do you

 

That’s sounding like an advantage TBH! 

[SteamyTea]

[billt]

2 hours ago, JSHarris said:

Looks like the collector has stagnated at 127 deg C because the ST pump has turned off, and the ST pump has probably turned off because the stat has turned it off.  My guess is that the stat that's set to 45 deg C may be the one that is controlling the ST, in which case it's satisfied, as the bottom of the tank is well over the 45 deg set point.

 

It's not unusual to see pretty high collector temperatures in the ST system when it's turned off.  Between 120 deg C and 140 deg C is about the normal max range in this condition, IIRC.

 

You're probably right about the system stagnating, however the cylinder thermostats shouldn't have anything to do with it. The ST system should be controlled entirely by the Resol controller.

 

The Resol controller should have a temperature sensor in the collector and one in the store. When the collector is some amount above the store temperature the solar pump will start and will continue to run until the collector temperature drops below the store temp or the store temperature exceeds some value which will be set in one of the controller parameters. The limit temperature looks to be set quite low to me; my system has got to 90C store temperature with several sunny days and no heating demand. However, my system is designed to cope with high temperatures (wood burning boiler) and has a mixing valve on the hot water feed to ensure that HW is always at a safe temperature (<50C).

 

I guess that this system doesn't have HW mixing valves (although these days they seem to be a requirement) and that the store temperature is limited for safety reasons. However, as the store was up to 65C the other day, it might be worth a little experiment with the controller settings. (They aren't very user friendly 'though!)

[Trw144]

When I was setting up my solar thermal on the home automation system I asked my solar supplier for the logic they programmed into the controller (no point re-inventing the wheel after all). One line of code was to switch the pump

off when the sensor was above 125 degrees - I never had chance to ask exactly why - I assumed it was to do with safety or the pump not liking temperatures that high.

[newhome]

So an update on the solar. Looks like it’s working as later on the settings were as follows:

 

col 64.4

tst 47.1

S3 68.5

% 70

h P 7

 

And the lower eBay stat was up to 68.5 from its earlier 56.5 and I’m pretty certain that the boiler didn’t fire up to do that. I’m not certain why the col temp got to 127 earlier in the day but it must have stopped for a bit I guess. 

 

The forecast is back to being rubbish again as per, and the col is down to 8c today so the sun did clearly shine on the righteous and they’re safely back in England and Wales now. 

 

I have to say that I’m struggling to get my head around the hot water staying in the TS because never in the years the thing has been installed has the hot water not run away somewhere. I keep looking at the little eBay stats in amazement . It’s also a novelty seeing the boiler on but not fired up as there was never a point where it was on but at rest previously. I want to knock on the cover and see if anyone is still in there . 

 

Electric bill was £254 last month (33 days) which seems a lot given that it’s only me here and I only heated 1 room previously. Hoping it might be a bit more economical going forwards! Am going to take regular readings to see how often the boiler is coming on and how much it is consuming, just for my own interest really to help me understand how the boiler is behaving as it is what it is. 

 

Every single room is between 20 and 22 degrees currently as they were all turned on to test the system Sun night. None of the rooms have dropped below the set temperature yet which has been lowered a bit as it was actually too hot in here lol so none of the rooms have shown as ‘heating’ in the last circa 36 hours. It’s also a novelty to walk round the house feeling that it’s warm as this house has always been cold previously. It’s weird how the abnormal becomes the new normal after a while and I’m now struggling to get my head around what should have been BAU / normal for this system lol. 

 

Am also going to set up a heatmiser profile to just heat the rooms I use as there is no point in heating the guest bedrooms for example. 

 

So all looking good so far, albeit that it feels like an alien concept to me at present. 

 

 

Edited April 10, 2018 by newhome

[Jeremy Harris]

Sounds like all is well and the controller is doing it's thing OK. 

 

The "COL" reading is the temperature at the hot side of the solar collector ("COL" being the abbreviation for "Collector"), and will vary a great deal, from close to the outside ambient temperature at night, to the stagnation temperature when the system has heated the tank to the set point when the sun's out.  The stagnation temperature can be between 120 deg C and 140 deg C, so the 127 deg C you had earlier was within range - the tank was just up to temperature and the controller had turned the solar system off, to avoid over heating the tank.

[newhome]

3 minutes ago, JSHarris said:

Sounds like all is well and the controller is doing it's thing OK. 

 

The "COL" reading is the temperature at the hot side of the solar collector ("COL" being the abbreviation for "Collector"), and will vary a great deal, from close to the outside ambient temperature at night, to the stagnation temperature when the system has heated the tank to the set point when the sun's out.  The stagnation temperature can be between 120 deg C and 140 deg C, so the 127 deg C you had earlier was within range - the tank was just up to temperature and the controller had turned the solar system off, to avoid over heating the tank.

 

Thanks! The system has been here for 8 years and I’m only just learning the terms and how it should operate . 

 

 

[PeterW]

I reset it all to factory apart from a couple of settings but the one that is interesting is the HP as thats the hours run. Apart from the 25 mins on Sunday night when we used the power of an empty tango can and some cold water to “influence” the pump into starting, the remaining time is purely from the controller. 

 

I will be really chuffed if it all works as planned as it’s been a bit of a challenge without knowing if the system was actually wired up properly in the first place ...! 

[SteamyTea]

10 hours ago, newhome said:

Am going to take regular readings to see how often the boiler is coming on and how much it is consuming

Said you would LOL

[newhome]

So, after the novelty of having functional heating for the last few days and fiddling round with the room temperatures what do people suggest I set them to? I currently have the main living space that I use set to 20c and the bedroom set to 18c which seems to work ok. Other rooms that I only transit through (eg hall) or don’t use at all (eg main lounge, guest bedrooms) are set to between 16c and 18c currently. Do people bother keeping rooms they don’t use heated at all? The heating and hot water is coming in at around £6 a day currently (all electric) when the solar thermal isn’t helping. The sun hasn’t been out enough for me to see how much of a difference that might make yet. 

[Ferdinand]

2 hours ago, newhome said:

So, after the novelty of having functional heating for the last few days and fiddling round with the room temperatures what do people suggest I set them to? I currently have the main living space that I use set to 20c and the bedroom set to 18c which seems to work ok. Other rooms that I only transit through (eg hall) or don’t use at all (eg main lounge, guest bedrooms) are set to between 16c and 18c currently. Do people bother keeping rooms they don’t use heated at all? The heating and hot water is coming in at around £6 a day currently (all electric) when the solar thermal isn’t helping. The sun hasn’t been out enough for me to see how much of a difference that might make yet. 

 

I think many of us probably turn our heating off completely for between 5 and 9 months each year. Last year mine was off from about April to September. I think others with more insulation do it March to October.

 

This spring was a little unusual :-o .

 

I run my main thermostat downstairs at about 21, and upstairs at about 18 in my room and 20 in mum’s via TRVs. Bathroom underfloor on for a bit in the morning for warm tootsies, and the other bedroom upstairs relies on open doors or gaps thereunder unless someone is coming to stay. For most of the time all this is on a few longish time clock periods per day say 4 hours morning, lunchtime and evening to allow the ufh temp to be low.

 

When it goes below zero I either put it on 247, or turn the flow temperature up, or some combination of the two.

 

Others differ markedly.

 

Ferdinand

 

[SteamyTea]

The number on the thermostat is pretty irrelevant.  Set the room/s to what you feel comfortable with for different times of the day/week.

I tend to only heat the part of the house that I live in, no heating upstairs.  My heating is totally off now and probably won't come back on till November/December (it was on more than normal as I was away a month and signs of damp appeared, I have also fixed a leak in the from room).

As for heating all or part of the house, the less wall area to volume area that is heated the better.  So imagine a room in the centre of the house that is at 20°C surrounded by a room that is at 10°C that is then surrounded by the outside world at 0°C.

That outer room is, in effect, part of the insulation.  Not quite as simple as that, but you get the idea.

[richi]

For conventional construction, it's a good idea to keep it warm enough to keep away dampness. Wet materials have a poorer U value, hence the "paradox" of needing less energy to heat a house for 24 hours with timed thermostats (vs. a conventional controller switching the system off overnight and during the day).

[newhome]

The heating was knackered for so long that apart from knowing that 20c is comfortable in the living area (which was the only room I actually had heat in before) it’s going to be a bit trial and error to get the rest right I think. I clearly don’t want it to be as cold as before, but I don’t want to set it for tropical and waste money on heating I don’t need. It was so weird walking into a house with thermostats registering 24c when the heating was finally working that first day but that was also way too hot even for sitting around. The dogs didn’t like it that hot either. 

 

I think I may switch all non used rooms down to 14 which at this time of year means that the heating should only fire up if it turns really cold again. I may also switch the thermostats to 7 days instead of 5 / 2 as some weekdays I work from home and other days I go to the office so I have different requirements on different days. Will be a bit trial and error I’m sure! 

 

It’s definitely not warm enough to switch off the heating yet. That’s generally sometime in May IIRC. And then it’s generally off until Sept although last year the boiler was fecked and it took until mid Nov to get someone to fix it so it was pretty baltic in here by then. 

 

 

[billt]

Our heating is never turned off by us; it monitors both the external and internal temperature and only runs when there is a need for heat. Why think about turning the heating off when you don't have to?

 

The temperatures have dropped since I started heating with wood! We now keep the living room, dining room and kitchen at about 19 and the other rooms at about 18 during occupancy periods; they set back to about 17 at other times.

 

You readily get used to lower temperatures than seem to be generally wanted if you wear a reasonable amount of clothing! And we were brought up in draughty houses which only had heating in one room, except for special occasions.

[newhome]

1 hour ago, billt said:

Why think about turning the heating off when you don't have to?

 

Well I don’t want to heat rooms that no one ever goes in, and I want to utilise the solar to heat the thermal store if I can during the day so I don’t want the electric boiler kicking in 24 x 7. My plan was to use it to heat rooms and water early in the morning, switch off at 7am when I leave for work if I go to the office, leave the solar to work during the day if it can, and then have the boiler switch on to heat up water and UFH ready for me to return in the evening. I’ve no idea if that’s a reasonable plan for this type of system tho! Very much at the learning stage! 

 

[Ferdinand]

4 hours ago, newhome said:

 

Well I don’t want to heat rooms that no one ever goes in, and I want to utilise the solar to heat the thermal store if I can during the day so I don’t want the electric boiler kicking in 24 x 7. My plan was to use it to heat rooms and water early in the morning, switch off at 7am when I leave for work if I go to the office, leave the solar to work during the day if it can, and then have the boiler switch on to heat up water and UFH ready for me to return in the evening. I’ve no idea if that’s a reasonable plan for this type of system tho! Very much at the learning stage! 

 

 

It depends how good your fabric is.

 

If you only need a tea light for 3 minutes AM and PM to heat the whole house, then the extra rooms cost 3p a year each to heat, and buggering about with doors and temperatures (and complicated control gear) is as useful for your welfare as counting nose-hairs on a live walrus by plucking them out one by one with tweezers.

 

If otoh your house is more like mine ie probably at about 2010 Regs Level then there may well be fewer losses (ie more than nearly zero) by a slightly more traditional heating strategy.

 

I tend to use a practice somewhere between the two.

 

(It is Saturday and I enjoyed a large Jack Daniels with my after dinner coffee, and I deny all responsibility for things I may say).

[newhome]

5 minutes ago, Ferdinand said:

If otoh your house is more like mine ie probably at about 2010 Regs Level then there may well be fewer losses (ie more than nearly zero) by a slightly more traditional heating strategy.

 

 

Mine was 2006 regs level so probably worse than yours. And I know I don’t get zero losses. 

 

 

[SteamyTea]

1 hour ago, newhome said:

My plan was to use it to heat rooms and water early in the morning, switch off at 7am when I leave for work if I go to the office

Ideally you want the store as cold as practicable so that the ST can do its work.  I am sure you will get a feel for it pretty soon now it is working.

[billt]

My point is that the system is autonomous; it maintains the temperatures that I want in the rooms that I want at the times that I want heat. In warm weather heating will not be required and the system "knows" this so heat will not be delivered and I do not have to modify the controls at all. With the controls that I've seen pictured for your system I'd imagine that you shouldn't have to 'switch the heating off' at all.

 

All our rooms are used, but they all have individual control, so it wouldn't be much of an issue to not heat individual rooms; in our house that wouldn't achieve much as it responds very slowly to heat changes and the rooms aren't thermally isolated.

[newhome]

4 minutes ago, SteamyTea said:

Ideally you want the store as cold as practicable so that the ST can do its work.  I am sure you will get a feel for it pretty soon now it is working.

 

I’m still not really sure how I can tell if the solar is heating the store. I’m hoping that it becomes more apparent in the proper summer when the heating is off and I’m just using DHW. 

[SteamyTea]

Jot down what your electric meter says every morning and evening, that should give you a decent idea of what is going on.

[Hecateh]

3 hours ago, Ferdinand said:

is as useful for your welfare as counting nose-hairs on a live walrus by plucking them out one by one with tweezers.

brilliant metaphor

 

can I share it?

 

[newhome]

6 hours ago, billt said:

My point is that the system is autonomous; it maintains the temperatures that I want in the rooms that I want at the times that I want heat. In warm weather heating will not be required and the system "knows" this so heat will not be delivered and I do not have to modify the controls at all. With the controls that I've seen pictured for your system I'd imagine that you shouldn't have to 'switch the heating off' at all.

 

 

When I say switched off I mean the temps are set to be lower on the room stats during the times that I’m not here so the heating / boiler doesn’t come on. If there was a huge cold snap I guess it might have to come on even to maintain the lower temperature (which is 18 in the main living rooms rising to 20 when I’m physically here). When I return home the temperature is set at 20 so the boiler either comes on or not depending on whether the temperature has dropped below that value. So I guess it is autonomous, but I’m learning how to set it optimally as a 24kw electric boiler coming on all the time is a bit spendy. 

 

Does 24kw mean that it will use 24kw every hour it fires or something else?