My Nightmare Heating System

[newhome]

Here’s the bit from the electrical test if useful. 

 

 

[Nickfromwales]

33 minutes ago, ProDave said:

I have to go out now, I will look for the manual later (unless someone finds it first and posts a link)

 

Do you have a 3 phase supply? I assume so (still waiting for pictures of your meters and consumer units )  Otherwise 24KW (105A) is too much for a single phase supply

Manual already posted. 

[MikeSharp01]

3 phase just means you effectivey have three normal mains connections. To run 24 kilowatt boiler a single phase - that most of us have, will not be sufficient. It also means that the wiring from meter to boiler needs to be treated with care as 3 phase is more lethal than single phase.

[Nickfromwales]

7 minutes ago, MikeSharp01 said:

3 phase is more lethal than single phase.

Only if you stick your fingers in Mike.....only if you stick your fingers in. 

[Nickfromwales]

Did the sparky look like this ?

 

[Nickfromwales]

PS, I am doing a draft in the background.  

[ProDave]

1 hour ago, Nickfromwales said:

Manual already posted. 

I missed that.

 

Her it i again for anyone else looking https://www.electric-heatingcompany.co.uk/wp-content/uploads/2013/07/COMET-f.495.pdf

 

The manual is not that useful as in this application is it not "heating only" or "heating and hot water"  it is "heating a thermal store"  The closest would be the "heating only" installarion but substitute cylnder thermostat for room thermostat (Figure 8 in the manual)

 

HOWEVER it is not that simple. There is no point whatsoever using a programmer to turn it on and off as you have an off peak supply with unknown on times, you know how many hours it will be on, but not when.  So if I were doing it, I would use a relay, that is energised by a feed from the E2000 supply and substitute it's normally open contacts in place of terminals 1 and 3 of the programmer shown in Figure 8

 

Exactly how to do that I can't say until I see the meters and consumer units.

[ProDave]

2 hours ago, newhome said:

Here’s the bit from the electrical test if useful. 

 

 

That confirms a 3 phase supply.

 

Can you post some more pages, specifically there will be a couple of pages "schedule of test results"

 

[newhome]

2 minutes ago, ProDave said:

 

HOWEVER it is not that simple. There is no point whatsoever using a programmer to turn it on and off as you have an off peak supply with unknown on times, you know how many hours it will be on, but not when.  So if I were doing it, I would use a relay, that is energised by a feed from the E2000 supply and substitute it's normally open contacts in place of terminals 1 and 3 of the programmer shown in Figure 8

 

Exactly how to do that I can't say until I see the meters and consumer units.

 

The times seem to be the same every day. 3 x 2 hour slots. I hear a ‘click’ when the time starts. 

[ProDave]

2 minutes ago, newhome said:

 

The times seem to be the same every day. 3 x 2 hour slots. I hear a ‘click’ when the time starts. 

Which means the boiler at the moment is only operating 6 hours a day with no guarantee that those 6 hours fall within the 18 hours of cheap rate (some of it will but probably not all)

 

[MikeSharp01]

Relay is an electric switch. It, usually takes a very small, tiny, amount of electricily to turn a device that uses a large amount of electricity on and or off.

[MikeSharp01]

1 hour ago, Nickfromwales said:

Only if you stick your fingers in Mike.....only if you stick your fingers in. 

Yes but if you are unsure what you are looking at how would you know definitely not to touch.

[newhome]

1 hour ago, ProDave said:

Which means the boiler at the moment is only operating 6 hours a day with no guarantee that those 6 hours fall within the 18 hours of cheap rate (some of it will but probably not all)

 

 

I could get boiler to operate 24 hours a day if I wanted to. It only switches off when I physically switch it off or control the on and off times with the wall controller (which is what I do currently). I’m setting it like a normal gas and rads boiler just now coming on around 5am to heat water for a shower, then switch off at about 8am, and then on about an hour before I get home from work and off around 11pm. I know that’s not optimal for this type of system but it’s the only way it seems to be economical really. 

[newhome]

Here is the full electrical test. There were a few things to address that were done and signed off later. 

 

Will add later as struggling to remove my address from the phone! 

 

 

 

Edited February 21, 2018 by newhome

[ProDave]

14 minutes ago, newhome said:

 

I could get boiler to operate 24 hours a day if I wanted to. It only switches off when I physically switch it off or control the on and off times with the wall controller (which is what I do currently). I’m setting it like a normal gas and rads boiler just now coming on around 5am to heat water for a shower, then switch off at about 8am, and then on about an hour before I get home from work and off around 11pm. I know that’s not optimal for this type of system but it’s the only way it seems to be economical really. 

The point I am trying to make is separate the actions of heating up the store and the times you use heat from the store.

 

The most economical way will be have the boiler coming on only for the 18 hours when it is at the cheap tarrif. It will stop when the tank is up to full temperature so you won't be wasting heat. Bit I am pretty certain you won't be able to do that without some alterations.

 

At the moment there is a fair chance that a lot of your heating will be done at the cheap rate but also it will be certain much of it will be using the peak rate at the moment.

[Nickfromwales]

Right then, here we go......

Order of events :- ( chapter one lol ).

 

Electric boiler which is sealed and pressurised. Thats the reason why the pressure needs topping up occasionally. It should run at around 1.5 bar- 2 bar, rising when hot, falling when cool. 

 

Vertically mounted rectangular white box to the left of the boiler, and silver pump to the left of that :

White box is a PHE ( Plate Heat Exchanger ), required to hydraulically separate the sealed and pressurised body of water in the boiler from the open pipe 'gravity' fed body of water in the TS ( thermal store ).

Silver pump is the pump required to circulate the water in the TS through the PHE so it can be heated by the PHE, the other side of the PHE is heated by the boiler.

 

The black plastic tank in the cupboard is the F&E ( Feed and Expansion ) tank which keeps the TS topped up without the need to pressurise that too, eg a bit less maintenance intensive that way. Needs no attention other than to top up with inhibitor perhaps. 

 

Silver pump lower left TS. That pump circulates the water in the TS through another PHE, the one in a silver / metal box affixed to the side of the tank with the pipe going to the upper of the TS side. That heats the DHW ( domestic hot water ( what comes out of your hot taps )) in the same way the boiler PHE heats the TS. Under that pump is a thermo head which regulates the flow temp through that circuit. A naff idea as the DHW is serviced by a TMV ( thermostatic mixing valve ) anyway, thus giving you control over your maximum DHW delivery temp. A TMV is necessary with a TS as you can have very high / near scalding temperature DHW without it  I assume that either runs off a Hot Water time clock setting, or is operated by a flow switch that senses you opening a tap and fires that particular pump up for the duration the tap is open. Anyone's guess without being there.....and poking @MikeSharp01's fingers in the corresponding pump connections and then opening the taps to see if he screams and when / how long etc

 

The other two green pumps and their corresponding red - topped TMV's are space ( central ) heating flows. eg one ( the upper hotter coil ) could be going to 1st floor heating radiators, so would be set to around 55-65oC, and the other ( the lower cooler coil ) could be going to the UFH manifolds, so set at 35-40oC, hence the lack of pump and blending valve on the UFH manifolds. The water that is pumped to the UFH has already been cooled down to the correct temp by the dedicated TMV before going into the UFH loops. IMO an inherently flawed design, but it'll work if set up correctly. 

 

At the top of the TS you have the Quenching Coil, ONLY NEEDED WITH A SOLID FUEL HEAT SOURCE  As you have stated that you don't have / were never having a WBS ( wood burning stove ) then fitting that was a waste of time and money. The PRedV ( with the gauge thats showing 6.5 bar, which I missed because I'm blind ) is there to limit the pressure and flow that arrives at the Quenching Coil control valve so it can operate smoothly and accurately. That valve is opened by a capillary probe that heats up and the hydraulic fluid inside expands with heat. That fluid expands and opens the control valve according to how hot the TS is, eg slightly over temp, a trickle of cold mains water, way over temp, a high flow of cold water. A good system in principle, and used on many good quality sealed and pressurised WBS's, but has no place in your house as its function is redundant. My recommendation is to remove all that and bin it, capping the cold feed to the PRedV as its knackered anyway ( it would be showing around 3 bar if functioning properly ). 

 

The black circular bit halfway up is the backup 3Kw ( assumed ) immersion heater. That should be turned on by a switch on the wall for emergency use only. Follow the cable and ensure that the switch ( usually a white switch the size of a light switch with a red neon light on it ) is off. 

 

The white rectangular thermostats ( cylinder stats ) x3, from the top down so highest is 1:

1) Summer setting - The boiler is controlled by this stat ONLY, when space heating is not required. That allows the boiler to only heat the upper portion of the TS so you can get DHW only without heating the entire TS and wasting energy unnecessarily.  

2) and 3) Winter setting - Stat 1 gets ignored and 2 & 3 come into play. I have no idea why 2 stats would be so close together but tbh I think they ( technical ) may have given me duff info and its actually 1 & 2 that govern summer setting with 3 doing the winter 'full heat' of the TS. If its not, thats how I'd set it up, but id also simplify by ditching the middle stat ( stat 2 ) as I really see no need for the third one. The wires that disappear into unions on the TS are ( assumed ) the temperature probes for the ST ( solar thermal ) system, so I dont see the other rotary cylinder stats doing any of the ST referencing AFAIC.

 

Principle of operation ( as advised from technical support ) :

You should have a two-channel time-clock for toggling between summer and winter 'mode' which you will have to do manually as required. You may also have another time-clock for DHW production, depending on how its been configured. If it has a flow switch after the DHW PHE output then you might not have a DHW time-clock. Anyones guess at the moment tbh. Selecting winter mode kicks all the space heating controls into action and starts the various pumps and faff to work accordingly. Simple eh ?!?

 

What to do next :

 

1) Roll your sleeves up and shout very loudly at your boiler and TS for approximately 3 minutes, only stopping to breathe in again. That'll reset everything and show it that you mean business, probably. When done, read all the above again which will allow your blood pressure to return to normal again. You'll feel better then. 

2) Turn off the big chunky switch to the boiler so it goes dead.

3) Turn off all the time-clocks and turn down all the ROOM / HOUSE stats.

4) Turn the 3 TS cylinder stats to their lowest positions, marking first with a pencil their current setting. 

5) Wait for the TS to go cold. 

6) Switch the boiler back on, report what it does for the first 15 mins. It should cycle for maybe 2 minutes and then go into standby, whilst it does a self-diagnostic, or simply do nothing at all. It should not run and heat up the white PHE, and the silver pump for the white PHE should not run. The system should now simply be sitting in standby aka 'holiday mode'.

7) Assuming the above went accordingly ( lol ), turn on all the heating time controls you can find, but leave all ROOM / HOUSE stats set to mimimum, including the one some cock has fitted in a cupboard. Do NOT switch the black immersion heater on. 

8) Turn TS cylinder stat 3 to 65oC. Report what happens for the first 5 minutes. The boiler should kick in, the pump and PHE adjacent should run and all get hot and the TS should then proceed to heat up entirely until the cylinder stat tells the boiler to switch off again, maybe an hour or so, maybe a bit less / more. This is the critical bit which will identify if the wiring is in order or not. The boiler should, at this point, be receiving instruction to heat until stat 3 tells it otherwise. If not the most recent pipe butcher has fecked something up whilst charging you for the pleasure. 

9) If the boiler does not kick in within the 5 min period, turn up the stat in the cupboard and see if that has been put in line with the other controls, making sure its partnered time-clock is deffo on too. 

10) If the boiler still doesn't kick in, turn up TS stat 2 to 65oC. 

11) If the boiler still doesn't kick in, turn up TS stat 3 to 65oC.

12) If the boiler still doesn't kick in, turn the ROOM / HOUSE stats back up and set things back to how you had them.

13) Note when the heating / whatever came on during the above and file your report here and we'll go from there. 

 

As Dave has said, you need to try and make heating on / consumption coincide with each other to maximise efficiency. Its not ideal tbh as the TS will go cold very quickly ( so you'll soon run out of DHW between heating intervals ). The only problem is is that the system has been designed around a busy full household and its just yourself ( IIRC ) there, so basically its like driving a double-decker bus with only one passenger on board. Also, heating the TS for 3 x 2 hour bursts / 24hrs won't even scratch the surface. Whenever heating is on, the boiler needs to be on. Whenever DHW is wanted, likewise. 

I think id have designed it differently but I also think I would have chosen different lottery numbers last week too as I didn't win....hindsight being a wonderful thing and all that. 

 

Chapter two to follow after some feedback. 

[newhome]

52 minutes ago, ProDave said:

The point I am trying to make is separate the actions of heating up the store and the times you use heat from the store.

 

The most economical way will be have the boiler coming on only for the 18 hours when it is at the cheap tarrif. It will stop when the tank is up to full temperature so you won't be wasting heat. Bit I am pretty certain you won't be able to do that without some alterations.

 

At the moment there is a fair chance that a lot of your heating will be done at the cheap rate but also it will be certain much of it will be using the peak rate at the moment.

 

How does it know when to charge peak rate if the heating is only wired to one of the meters with a single reading? Think I don’t understand how these things work as I’ve never had 2 meters before. 

 

 

[MikeSharp01]

Brilliant post Nick - love the TLA (Three letter abbreviation) explanations. It really is quite a system is it not.

[MikeSharp01]

As I understand it the second meter is the economy 2000 meter and is the one that supplies the boiler and is the one that takes the three phase electricity into the boiler. Somewhere on that meter, or very close to it in a separate box will be a switch that is controlled by the electric company and is used to tell your system that the electricity is cheap. It would be usual to use that switch to control the boiler so it only runs when you have cheap electricity. Can you photo the meter, perhaps you have I think I may have missed a bit of this series today, so we can see because we need to work out if that switch is still being used or if the timer, fitted as you described, is running it. If they are both in the circuit then the boiler will only run when the electric company switch is on and the timer is on. If just the timer is in control hen as as @ProDave  says you may or may not be using cheap electricity as it (the timer) knows nothing about the cheap rate times.

[newhome]

2 minutes ago, MikeSharp01 said:

As I understand it the second meter is the economy 2000 meter and is the one that supplies the boiler and is the one that takes the three phase electricity into the boiler. Somewhere on that meter, or very close to it in a separate box will be a switch that is controlled by the electric company and is used to tell your system that the electricity is cheap. It would be usual to use that switch to control the boiler so it only runs when you have cheap electricity. Can you photo the meter, perhaps you have I think I may have missed a bit of this series today, so we can see because we need to work out if that switch is still being used or if the timer, fitted as you described, is running it. If they are both in the circuit then the boiler will only run when the electric company switch is on and the timer is on. If just the timer is in control hen as as @ProDave  says you may or may not be using cheap electricity as it (the timer) knows nothing about the cheap rate times.

 

 

Thanks! Not posted the meters yet as still at work. Will be home later to take pics! 

[ProDave]

12 minutes ago, newhome said:

 

How does it know when to charge peak rate if the heating is only wired to one of the meters with a single reading? Think I don’t understand how these things work as I’ve never had 2 meters before. 

 

 

I hope all will be revealed when I see the meter pics.

 

There will almost certainly be a "radio teleswitch" which allows the supplier to turn on and off the off peak rate when it likes.  You need to tap into this to control the boiler. I know how to do it with conventional E7 or E10 but I am not familliar with how your system is wired.

[HerbJ]

It might be that there are two timers controlling the boiler - the E2000 time switch, installed as part of the metering equipment , and also a second timeswitch controlling the bolier within the  E2000 period,  as a method  to limit  electrical costs???

[newhome]

Thank you so much @Nickfromwales! You are a star! I don’t claim to have understood all that you’ve posted but when I’m home I will read it in conjunction with the visual view and it may make more sense. 

 

The ‘cock in the cupboard’ was the local plumber who installed that thermostat in the utility room just outside the boiler room. I thought that was a bit odd as even I know that you don’t put a thermostat that controls the boiler right next to the bleedin boiler! 

 

 

[MikeSharp01]

34 minutes ago, Nickfromwales said:

Vertically mounted rectangular white box to the left of the boiler, and silver pump to the left of that :

White box is a PHE ( Plate Heat Exchanger ), required to hydraulically separate the sealed and pressurised body of water in the boiler from the open pipe 'gravity' fed body of water in the TS ( thermal store ).

Silver pump is the pump required to circulate the water in the TS through the PHE so it can be heated by the PHE, the other side of the PHE is heated by the boiler.

@newhomeIs the temp gauge above the silver pump (on the heat exchanger to thermal store circuit) the one that now only goes to 50 when it used to go to 60? [Or is the temp dial on another cicuit I cannot make out from the photo?]

 

Think I have it I can see the other temp gauge now I am on my PC. What temperature does the first temp gauge, mentioned above, get to?

Edited February 21, 2018 by MikeSharp01
Spotted other gauge.

[Nickfromwales]

1 hour ago, MikeSharp01 said:

Brilliant post Nick - love the TLA (Three letter abbreviation) explanations. It really is quite a system is it not.

Yup. It really only needs a bit of pruning and a full rewire so an installer is able to demonstrate it working, properly, and leave it automated. It's just been made overly complicated and it's getting a bit under-used, so economics may well have to stay out of it. 

Running it should just be selecting between off ( holiday ), on summer or on winter ( hot water or heating and hot water ) . Thermal stores need to be kept warm or hot though ( for any time you need hot water during the day ) so it's not a tame beast I'm afraid. A TS is really 'all or bugger all'.